Diabetes mellitus type 1 and type 2 by mohammad yaser hussain

DIABETES MELLITUS TYPE 1 AND TYPE 2

Diabetes mellitus (DM), commonly referred to as diabetes, is a group of metabolic diseases in which there are high blood sugar levels over a prolonged period.[2] Symptoms of high blood sugar

include frequent urination, increased thirst, and increased hunger. If left untreated, diabetes can cause many complications.[3] Acute complications include diabetic ketoacidosis and nonketotic hyperosmolar coma.[4] Serious long-term complications include cardiovascular disease, stroke, chronic kidney failure, foot ulcers, and damage to the eyes.[3]

Diabetes is due to either the pancreas not producing enough insulin or the cells of the body not responding properly to the insulin produced.[5] There are three main types of diabetes mellitus:

Type 1 DM results from the pancreas's failure to produce enough insulin. This form was previously referred to as "insulin-dependent diabetes mellitus" (IDDM) or "juvenile diabetes". The cause is unknown.[3]

Type 2 DM begins with insulin resistance, a condition in which cells fail to respond to insulin properly.[3] As the disease progresses a lack of insulin may also develop.[6] This form was previously referred to as "non insulin-dependent diabetes mellitus" (NIDDM) or "adult-onset diabetes". The primary cause is excessive body weight and not enough exercise.[3]

Gestational diabetes , is the third main form and occurs when pregnant women without a previous history of diabetes develop high blood-sugar levels.[3]

Prevention and treatment involve a healthy diet, physical exercise, maintaining a normal body weight, and avoiding use of tobacco. Control of blood pressure and maintaining proper foot care are important for people with the disease. Type 1 DM must be managed with insulin injections.[3] Type 2 DM may be treated with medications with or without insulin.[7] Insulin and some oral medications can cause low blood sugar.[8] Weight loss surgery in those with obesity is sometimes an effective measure in those with type 2 DM.[9] Gestational diabetes usually resolves after the birth of the baby.[10]

As of 2015, an estimated 415 million people have diabetes worldwide,[11] with type 2 DM making up about 90% of the cases.[12][13] This represents 8.3% of the adult population,[13] with equal rates in both women and men.[14] From 2012 to 2015, diabetes is estimated to have resulted in 1.5 to 5.0 million deaths each year.[7][11] Diabetes at least doubles a person's risk of death.[3] The number of people with diabetes is expected to rise to 592 million by 2035.

Signs and symptoms

2016

Apollo hospitals

MOHAMMAD YASER HUSSAIN

Overview of the most significant symptoms of diabetes

The classic symptoms of untreated diabetes are weight loss, polyuria (increased urination), polydipsia (increased thirst), and polyphagia (increased hunger).[18] Symptoms may develop rapidly (weeks or months) in type 1 DM, while they usually develop much more slowly and may be subtle or absent in type 2 DM.

Several other signs and symptoms can mark the onset of diabetes, although they are not specific to the disease. In addition to the known ones above, they include blurry vision, headache, fatigue, slow healing of cuts, and itchy skin. Prolonged high blood glucose can cause glucose absorption in the lens of the eye, which leads to changes in its shape, resulting in vision changes. A number of skin rashes that can occur in diabetes are collectively known as diabetic dermadromes.

Diabetic emergencies

Low blood sugar is common in persons with type 1 and type 2 DM. Most cases are mild and are not considered medical emergencies. Effects can range from feelings of unease, sweating, trembling, and increased appetite in mild cases to more serious issues such as confusion, changes in behavior, seizures, unconsciousness, and (rarely) permanent brain damage or death in severe cases.[19][20] Mild cases are self-treated by eating or drinking something high in sugar. Severe cases can lead to unconsciousness and must be treated with intravenous glucose or injections with glucagon.

People (usually with type 1 DM) may also experience episodes of diabetic ketoacidosis, a metabolic disturbance characterized by nausea, vomiting and abdominal pain, the smell of acetone on the breath, deep breathing known as Kussmaul breathing, and in severe cases a decreased level of consciousness.[21]

A rare but equally severe possibility is hyperosmolar nonketotic state, which is more common in type 2 DM and is mainly the result of dehydration.[21]

Complications

Main article: Complications of diabetes mellitus

All forms of diabetes increase the risk of long-term complications. These typically develop after many years (10–20), but may be the first symptom in those who have otherwise not received a diagnosis before that time.

The major long-term complications relate to damage to blood vessels. Diabetes doubles the risk of cardiovascular disease [22] and about 75% of deaths in diabetics are due to coronary artery disease.[23] Other "macrovascular" diseases are stroke, and peripheral vascular disease.

The primary complications of diabetes due to damage in small blood vessels include damage to the eyes, kidneys, and nerves.[24] Damage to the eyes, known as diabetic retinopathy, is caused by damage to the blood vessels in the retina of the eye, and can result in gradual vision loss and blindness.[24] Damage to the kidneys, known as diabetic nephropathy, can lead to tissue scarring, urine protein loss, and eventually chronic kidney disease, sometimes requiring dialysis or kidney transplant.[24] Damage to the nerves of the body, known as diabetic neuropathy, is the most common complication of diabetes.[24] The symptoms can include numbness, tingling, pain, and altered pain sensation, which can lead to damage to the skin. D iabetes-related foot problems (such as diabetic foot ulcers) may occur, and can be difficult to treat, occasionally requiring amputation. Additionally, proximal diabetic neuropathy causes painful muscle wasting and weakness.

There is a link between cognitive deficit and diabetes. Compared to those without diabetes, those with the disease have a 1.2 to 1.5-fold greater rate of decline in cognitive function.[25]

Causes

Comparison of type 1 and 2 diabetes[12]

Feature Type 1 diabetes Type 2 diabetes

Onset Sudden Gradual

Age at onset Mostly in children Mostly in adults

Body size Thin or normal[26] Often obese

Ketoacidosis Common Rare

Autoantibodies Usually present Absent

Endogenous insulin Low or absent Normal, decreasedor increased

Concordancein identical twins 50% 90%

Prevalence ~10% ~90%

Diabetes mellitus is classified into four broad categories: type   1 , type   2 , gestational diabetes, and "other specific types".[5] The "other specific types" are a collection of a few dozen individual causes.[5] The term "diabetes", without qualification, usually refers to diabetes mellitus.

Type 1

Main article: Diabetes mellitus type 1

Type 1 diabetes mellitus is characterized by loss of the insulin-producing beta cells of the islets of Langerhans in the pancreas, leading to insulin deficiency. This type can be further classified as immune-mediated or idiopathic. The majority of type 1 diabetes is of the immune-mediated nature, in which a T-cell-mediated autoimmune attack leads to the loss of beta cells and thus insulin.[27] It causes approximately 10% of diabetes mellitus cases in North America and Europe. Most affected people are otherwise healthy and of a healthy weight when onset occurs. Sensitivity and responsiveness to insulin are usually normal, especially in the early stages. Type 1 diabetes can affect children or adults, but was traditionally termed "juvenile diabetes" because a majority of these diabetes cases were in children.

"Brittle" diabetes, also known as unstable diabetes or labile diabetes, is a term that was traditionally used to describe the dramatic and recurrent swings in glucose levels, often occurring for no apparent reason in insulin-dependent diabetes. This term, however, has no biologic basis and should not be used.[28] Still, type 1 diabetes can be accompanied by irregular and unpredictable high blood sugar levels, frequently with ketosis, and sometimes with serious low blood sugar levels. Other complications include an impaired counterregulatory response to low blood sugar, infection, gastroparesis (which leads to erratic absorption of dietary carbohydrates), and endocrinopathies (e.g., Addison's disease).[28] These phenomena are believed to occur no more frequently than in 1% to 2% of persons with type 1 diabetes.[29]

Type 1 diabetes is partly inherited, with multiple genes, including certain HLA genotypes, known to influence the risk of diabetes. In genetically susceptible people, the onset of diabetes can be triggered by one or more environmental factors, such as a viral infection or diet. There is some evidence that suggests an association between type 1 DM and Coxsackie B4 virus. Unlike type 2 DM, the onset of type 1 diabetes is unrelated to lifestyle.

Type 2

Main article: Diabetes mellitus type 2

Type 2 DM is characterized by insulin resistance, which may be combined with relatively reduced insulin secretion.[5] The defective responsiveness of body tissues to insulin is believed to involve the insulin receptor. However, the specific defects are not known. Diabetes mellitus cases due to a known defect are classified separately. Type 2 DM is the most common type of diabetes mellitus.

In the early stage of type 2, the predominant abnormality is reduced insulin sensitivity. At this stage, high blood sugar can be reversed by a variety of measures and medications that improve insulin sensitivity or reduce the liver's glucose production.

Type 2 DM is due primarily to lifestyle factors and genetics.[30] A number of lifestyle factors are known to be important to the development of type 2 DM, including obesity (defined by a body mass index of greater than 30), lack of physical activity, poor diet, stress, and urbanization.[12] Excess body fat is associated with 30% of cases in those of Chinese and Japanese descent, 60–80% of cases in those of European and African descent, and 100% of Pima Indians and Pacific Islanders.[5] Even those who are not obese often have a high waist–hip ratio.[5]

Dietary factors also influence the risk of developing type 2 DM. Consumption of sugar-sweetened drinks in excess is associated with an increased risk.[31][32] The type of fats in the diet is also important, with saturated fats and trans fatty acids increasing the risk and polyunsaturated and monounsaturated fat decreasing the risk.[30] Eating lots of white rice also may increase the risk of diabetes.[33] A lack of exercise is believed to cause 7% of cases.[34]

Gestational diabetes

Main article: Gestational diabetes

Gestational diabetes mellitus (GDM) resembles type 2 DM in several respects, involving a combination of relatively inadequate insulin secretion and responsiveness. It occurs in about 2–10% of all pregnancies and may improve or disappear after delivery.[35] However, after pregnancy approximately 5–10% of women with gestational diabetes are found to have diabetes mellitus, most commonly type 2.[35] Gestational diabetes is fully treatable, but requires careful medical supervision throughout the pregnancy. Management may include dietary changes, blood glucose monitoring, and in some cases insulin may be required.

Though it may be transient, untreated gestational diabetes can damage the health of the fetus or mother. Risks to the baby include macrosomia (high birth weight), congenital heart and central nervous system abnormalities, and skeletal muscle malformations. Increased levels of insulin in a fetus's blood may inhibit fetal surfactant production and cause respiratory distress syndrome. A high blood bilirubin level may result from red blood cell destruction. In severe cases, perinatal death may occur, most commonly as a result of poor placental perfusion due to vascular impairment. Labor induction may be indicated with decreased placental function. A Caesarean

section may be performed if there is marked fetal distress or an increased risk of injury associated with macrosomia, such as shoulder dystocia.[citation needed]

Other types

Prediabetes indicates a condition that occurs when a person's blood glucose levels are higher than normal but not high enough for a diagnosis of type 2 DM. Many people destined to develop type 2 DM spend many years in a state of prediabetes.

Latent autoimmune diabetes of adults (LADA) is a condition in which type 1 DM develops in adults. Adults with LADA are frequently initially misdiagnosed as having type 2 DM, based on age rather than etiology.

Some cases of diabetes are caused by the body's tissue receptors not responding to insulin (even when insulin levels are normal, which is what separates it from type 2 diabetes); this form is very uncommon. Genetic mutations (autosomal or mitochondrial) can lead to defects in beta cell function. Abnormal insulin action may also have been genetically determined in some cases. Any disease that causes extensive damage to the pancreas may lead to diabetes (for example, chronic pancreatitis and cystic fibrosis). Diseases associated with excessive secretion of insulin-antagonistic hormones can cause diabetes (which is typically resolved once the hormone excess is removed). Many drugs impair insulin secretion and some toxins damage pancreatic beta cells. The ICD-10 (1992) diagnostic entity, malnutrition-related diabetes mellitus (MRDM or MMDM, ICD-10 code E12), was deprecated by the World Health Organization when the current taxonomy was introduced in 1999.[36]

Other forms of diabetes mellitus include congenital diabetes, which is due to genetic defects of insulin secretion, cystic fibrosis-related diabetes, steroid diabetes induced by high doses of glucocorticoids, and several forms of monogenic diabetes.

"Type 3 diabetes" has been suggested as a term for Alzheimer's disease as the underlying processes may involve insulin resistance by the brain.[37]

The following is a comprehensive list of other causes of diabetes:[38]

Genetic defects of β-cell function o Maturity onset diabetes of the

youngo Mitochondrial DNA mutations

Genetic defects in insulin processing or insulin action

o Defects in proinsulin conversiono Insulin gene mutationso Insulin receptor mutations

Exocrine pancreatic defects o Chronic pancreatitis o Pancreatectomy

Endocrinopathies o Growth hormone excess

(acromegaly)o Cushing syndrome o Hyperthyroidism o Pheochromocytoma o Glucagonoma

Infections o Cytomegalovirus infection o Coxsackievirus B

Drugs o Glucocorticoids

o Pancreatic neoplasia o Cystic fibrosis o Hemochromatosis o Fibrocalculous pancreatopathy

o Thyroid hormone o β-adrenergic agonists o Statins [39]

Pathophysiology

The fluctuation of blood sugar (red) and the sugar-lowering hormone insulin (blue) in humans during the course of a day with three meals — one of the effects of a sugar-rich vs a starch-rich meal is highlighted.

Mechanism of insulin release in normal pancreatic beta cells — insulin production is more or less constant within the beta cells. Its release is triggered by food, chiefly food containing absorbable glucose.

Insulin is the principal hormone that regulates the uptake of glucose from the blood into most cells of the body, especially liver, muscle, and adipose tissue. Therefore, deficiency of insulin or the insensitivity of its receptors plays a central role in all forms of diabetes mellitus.[40]

The body obtains glucose from three main places: the intestinal absorption of food, the breakdown of glycogen, the storage form of glucose found in the liver, and gluconeogenesis, the generation of glucose from non-carbohydrate substrates in the body.[41] Insulin plays a critical role

in balancing glucose levels in the body. Insulin can inhibit the breakdown of glycogen or the process of gluconeogenesis, it can stimulate the transport of glucose into fat and muscle cells, and it can stimulate the storage of glucose in the form of glycogen.[41]

Insulin is released into the blood by beta cells (β-cells), found in the islets of Langerhans in the pancreas, in response to rising levels of blood glucose, typically after eating. Insulin is used by about two-thirds of the body's cells to absorb glucose from the blood for use as fuel, for conversion to other needed molecules, or for storage. Lower glucose levels result in decreased insulin release from the beta cells and in the breakdown of glycogen to glucose. This process is mainly controlled by the hormone glucagon, which acts in the opposite manner to insulin.[42]

If the amount of insulin available is insufficient, if cells respond poorly to the effects of insulin (insulin insensitivity or insulin resistance), or if the insulin itself is defective, then glucose will not be absorbed properly by the body cells that require it, and it will not be stored appropriately in the liver and muscles. The net effect is persistently high levels of blood glucose, poor protein synthesis, and other metabolic derangements, such as acidosis.[41]

When the glucose concentration in the blood remains high over time, the kidneys will reach a threshold of reabsorption, and glucose will be excreted in the urine (glycosuria).[43] This increases the osmotic pressure of the urine and inhibits reabsorption of water by the kidney, resulting in increased urine production (polyuria) and increased fluid loss. Lost blood volume will be replaced osmotically from water held in body cells and other body compartments, causing dehydration and increased thirst (polydipsia).[41]

DiagnosisSee also: Glycated hemoglobin and Glucose tolerance test

WHO diabetes diagnostic criteria[44][45]  editCondition 2 hour glucose Fasting glucose HbA1c

Unit mmol/l(mg/dl) mmol/l(mg/dl) mmol/mol DCCT %Normal <7.8 (<140) <6.1 (<110) <42 <6.0

Impaired fasting glycaemia <7.8 (<140) ≥6.1(≥110) & <7.0(<126) 42-46 6.0–6.4Impaired glucose tolerance ≥7.8 (≥140) <7.0 (<126) 42-46 6.0–6.4

Diabetes mellitus ≥11.1 (≥200) ≥7.0 (≥126) ≥48 ≥6.5

Diabetes mellitus is characterized by recurrent or persistent high blood sugar, and is diagnosed by demonstrating any one of the following:[36]

Fasting plasma glucose level ≥ 7.0 mmol/l (126 mg/dl) Plasma glucose ≥ 11.1 mmol/l (200 mg/dl) two hours after a 75 g oral glucose load as in

a glucose tolerance test Symptoms of high blood sugar and casual plasma glucose ≥ 11.1 mmol/l (200 mg/dl) Glycated hemoglobin (HbA1C) ≥ 48 mmol/mol (≥ 6.5 DCCT %).[46]

A positive result, in the absence of unequivocal high blood sugar, should be confirmed by a repeat of any of the above methods on a different day. It is preferable to measure a fasting glucose level because of the ease of measurement and the considerable time commitment of formal glucose tolerance testing, which takes two hours to complete and offers no prognostic advantage over the fasting test.[47] According to the current definition, two fasting glucose measurements above 126 mg/dl (7.0 mmol/l) is considered diagnostic for diabetes mellitus.

Per the World Health Organization people with fasting glucose levels from 6.1 to 6.9 mmol/l (110 to 125 mg/dl) are considered to have impaired fasting glucose.[48] people with plasma glucose at or above 7.8 mmol/l (140 mg/dl), but not over 11.1 mmol/l (200 mg/dl), two hours after a 75 g oral glucose load are considered to have impaired glucose tolerance. Of these two prediabetic states, the latter in particular is a major risk factor for progression to full-blown diabetes mellitus, as well as cardiovascular disease.[49] The American Diabetes Association since 2003 uses a slightly different range for impaired fasting glucose of 5.6 to 6.9 mmol/l (100 to 125 mg/dl).[50]

Glycated hemoglobin is better than fasting glucose for determining risks of cardiovascular disease and death from any cause.[51]

The rare disease diabetes insipidus has similar symptoms to diabetes mellitus, but without disturbances in the sugar metabolism (insipidus means "without taste" in Latin) and does not involve the same disease mechanisms. Diabetes is a part of the wider condition known as metabolic syndrome.

PreventionSee also: Prevention of diabetes mellitus type 2

There is no known preventive measure for type 1 diabetes.[3] Type 2 diabetes can often be prevented by a person being a normal body weight, physical exercise, and following a healthful diet.[3] Dietary changes known to be effective in helping to prevent diabetes include a diet rich in whole grains and fiber, and choosing good fats, such as polyunsaturated fats found in nuts, vegetable oils, and fish.[52] Limiting sugary beverages and eating less red meat and other sources of saturated fat can also help in the prevention of diabetes.[52] Active smoking is also associated with an increased risk of diabetes, so smoking cessation can be an important preventive measure as well.[53]

ManagementMain article: Diabetes management

Diabetes mellitus is a chronic disease, for which there is no known cure except in very specific situations.[54] Management concentrates on keeping blood sugar levels as close to normal, without causing low blood sugar. This can usually be accomplished with a healthy diet, exercise, weight

loss, and use of appropriate medications (insulin in the case of type 1 diabetes; oral medications, as well as possibly insulin, in type 2 diabetes).

Learning about the disease and actively participating in the treatment is important, since complications are far less common and less severe in people who have well-managed blood sugar levels.[55][56] The goal of treatment is an HbA1C level of 6.5%, but should not be lower than that, and may be set higher.[57] Attention is also paid to other health problems that may accelerate the negative effects of diabetes. These include smoking, elevated cholesterol levels, obesity, high blood pressure, and lack of regular exercise.[57] Specialized footwear is widely used to reduce the risk of ulceration, or re-ulceration, in at-risk diabetic feet. Evidence for the efficacy of this remains equivocal, however.[58]

Lifestyle

See also: Diabetic diet

People with diabetes can benefit from education about the disease and treatment, good nutrition to achieve a normal body weight, and exercise, with the goal of keeping both short-term and long-term blood glucose levels within acceptable bounds. In addition, given the associated higher risks of cardiovascular disease, lifestyle modifications are recommended to control blood pressure.[59]

Medications

See also: Anti-diabetic medication

Medications used to treat diabetes do so by lowering blood sugar levels. There are a number of different classes of anti-diabetic medications. Some are available by mouth, such as metformin, while others are only available by injection such as GLP-1 agonists. Type 1 diabetes can only be treated with insulin, typically with a combination of regular and NPH insulin, or synthetic insulin analogs.[citation needed]

Metformin is generally recommended as a first line treatment for type 2 diabetes, as there is good evidence that it decreases mortality.[60] It works by decreasing the liver's production of glucose.[61] Several other groups of drugs, mostly given by mouth, may also decrease blood sugar in type II DM. These include agents that increase insulin release, agents that decrease absorption of sugar from the intestines, and agents that make the body more sensitive to insulin.[61] When insulin is used in type 2 diabetes, a long-acting formulation is usually added initially, while continuing oral medications.[60] Doses of insulin are then increased to effect.[60][62]

Since cardiovascular disease is a serious complication associated with diabetes, some have recommended blood pressure levels below 130/80 mmHg.[63] However, evidence supports less than or equal to somewhere between 140/90 mmHg to 160/100 mmHg; the only additional benefit found for blood pressure targets beneath this range was an isolated decrease in stroke risk, and this was accompanied by an increased risk of other serious adverse events.[64][65] A 2016 review found potential harm to treating lower than 140 mmHg.[66] Among medications that lower

blood pressure, angiotensin converting enzyme inhibitors (ACEIs) improve outcomes in those with DM while the similar medications angiotensin receptor blockers (ARBs) do not.[67] Aspirin is also recommended for patient with cardiovascular problems, however routine use of aspirin has not been found to improve outcomes in uncomplicated diabetes.[68]

Surgery

A pancreas transplant is occasionally considered for people with type 1 diabetes who have severe complications of their disease, including end stage kidney disease requiring kidney transplantation.[69]

Weight loss surgery in those with obesity and type two diabetes is often an effective measure.[70] Many are able to maintain normal blood sugar levels with little or no medications following surgery[71] and long-term mortality is decreased.[72] There however is some short-term mortality risk of less than 1% from the surgery.[73] The body mass index cutoffs for when surgery is appropriate are not yet clear.[72] It is recommended that this option be considered in those who are unable to get both their weight and blood sugar under control.[74]

Support

In countries using a general practitioner system, such as the United Kingdom, care may take place mainly outside hospitals, with hospital-based specialist care used only in case of complications, difficult blood sugar control, or research projects. In other circumstances, general practitioners and specialists share care in a team approach. Home telehealth support can be an effective management technique.[75]

EpidemiologyMain article: Epidemiology of diabetes mellitus

Rates of diabetes worldwide in 2000 (per 1,000 inhabitants) — world average was 2.8%.   no data  ≤ 7.5  7.5–15  15–22.5  22.5–30  30–37.5  37.5–45

  45–52.5  52.5–60  60–67.5  67.5–75  75–82.5  ≥ 82.5

Disability-adjusted life year for diabetes mellitus per 100,000 inhabitants in 2004   No data  <100  100–200  200–300  300–400  400–500  500–600

  600–700  700–800  800–900  900–1,000  1,000–1,500  >1,500

As of 2013, 382 million people have diabetes worldwide.[13] Type 2 makes up about 90% of the cases.[12][14] This is equal to 8.3% of the adult population[13] with equal rates in both women and men.[14]

In 2014, the International Diabetes Federation (IDF) estimated that diabetes resulted in 4.9 million deaths.[15] The World Health Organization (WHO) estimated that diabetes resulted in 1.5 million deaths in 2012, making it the 8th leading cause of death.[7] The discrepancy between the two estimates is due to the fact that cardiovascular diseases are often the cause of death for individuals with diabetes; the IDF uses modelling to estimate the amount of deaths that could be attributed to diabetes.[16] More than 80% of diabetic deaths occur in low and middle-income countries.[76]

Diabetes mellitus occurs throughout the world, but is more common (especially type 2) in more developed countries. The greatest increase in rates was expected to occur in Asia and Africa, where most people with diabetes will probably live in 2030.[77] The increase in rates in developing countries follows the trend of urbanization and lifestyle changes, including a "Western-style" diet. This has suggested an environmental (i.e., dietary) effect, but there is little understanding of the mechanism(s) at present.[77]

HistoryMain article: History of diabetes

Diabetes was one of the first diseases described,[78] with an Egyptian manuscript from c. 1500 BCE mentioning "too great emptying of the urine".[79] The first described cases are believed to be of type 1 diabetes.[79] Indian physicians around the same time identified the disease and classified it as madhumeha or "honey urine", noting the urine would attract ants.[79] The term "diabetes" or "to pass through" was first used in 230 BCE by the Greek Apollonius of Memphis.[79] The disease

was considered rare during the time of the Roman empire, with Galen commenting he had only seen two cases during his career.[79] This is possibly due to the diet and life-style of the ancient people, or because the clinical symptoms were observed during the advanced stage of the disease. Galen named the disease "diarrhea of the urine" (diarrhea urinosa). The earliest surviving work with a detailed reference to diabetes is that of Aretaeus of Cappadocia (2nd or early 3rd century CE). He described the symptoms and the course of the disease, which he attributed to the moisture and coldness, reflecting the beliefs of the "Pneumatic School". He hypothesized a correlation of diabetes with other diseases and he discussed differential diagnosis from the snakebite which also provokes excessive thirst. His work remained unknown in the West until the middle of the 16th century when, in 1552, the first Latin edition was published in Venice.[80]

Type 1 and type 2 diabetes were identified as separate conditions for the first time by the Indian physicians Sushruta and Charaka in 400-500 CE with type 1 associated with youth and type 2 with being overweight.[79] The term "mellitus" or "from honey" was added by the Briton John Rolle in the late 1700s to separate the condition from diabetes insipidus, which is also associated with frequent urination.[79] Effective treatment was not developed until the early part of the 20th century, when Canadians Frederick Banting and Charles Herbert Best isolated and purified insulin in 1921 and 1922.[79] This was followed by the development of the long-acting insulin NPH in the 1940s.[79]

Etymology

The word diabetes (/ˌdaɪ.əˈbiːtiːz/ or /ˌdaɪ.əˈbiːtᵻs/) comes from Latin diabētēs, which in turn comes from Ancient Greek διαβήτης (diabētēs) which literally means "a passer through; a siphon."[81] Ancient Greek physician Aretaeus of Cappadocia (fl. 1st century CE) used that word, with the intended meaning "excessive discharge of urine", as the name for the disease.[82][83][84] Ultimately, the word comes from Greek διαβαίνειν (diabainein), meaning "to pass through,"[81] which is composed of δια- (dia-), meaning "through" and βαίνειν (bainein), meaning "to go".[82] The word "diabetes" is first recorded in English, in the form diabete, in a medical text written around 1425.

The word mellitus (/mᵻˈlaɪtəs/ or /ˈmɛlᵻtəs/) comes from the classical Latin word mellītus, meaning "mellite"[85] (i.e. sweetened with honey;[85] honey-sweet[86]). The Latin word comes from mell-, which comes from mel, meaning "honey";[85][86] sweetness;[86] pleasant thing,[86] and the suffix -ītus,[85] whose meaning is the same as that of the English suffix "-ite".[87] It was Thomas Willis who in 1675 added "mellitus" to the word "diabetes" as a designation for the disease, when he noticed the urine of a diabetic had a sweet taste (glycosuria).[83] This sweet taste had been noticed in urine by the ancient Greeks, Chinese, Egyptians, Indians, and Persians.

Society and cultureFurther information: List of films featuring diabetes

The 1989 "St. Vincent Declaration"[88][89] was the result of international efforts to improve the care accorded to those with diabetes. Doing so is important not only in terms of quality of life and life

expectancy, but also economically—expenses due to diabetes have been shown to be a major drain on health—and productivity-related resources for healthcare systems and governments.

Several countries established more and less successful national diabetes programmes to improve treatment of the disease.[90]

People with diabetes who have neuropathic symptoms such as numbness or tingling in feet or hands are twice as likely to be unemployed as those without the symptoms.[91]

In 2010, diabetes-related emergency room (ER) visit rates in the United States were higher among people from the lowest income communities (526 per 10,000 population) than from the highest income communities (236 per 10,000 population). Approximately 9.4% of diabetes-related ER visits were for the uninsured.[92]

Naming

The term "type 1 diabetes" has replaced several former terms, including childhood-onset diabetes, juvenile diabetes, and insulin-dependent diabetes mellitus (IDDM). Likewise, the term "type 2 diabetes" has replaced several former terms, including adult-onset diabetes, obesity-related diabetes, and noninsulin-dependent diabetes mellitus (NIDDM). Beyond these two types, there is no agreed-upon standard nomenclature.

Diabetes mellitus is also occasionally known as "sugar diabetes" to differentiate it from diabetes insipidus.[93]

Other animalsMain articles: Diabetes in dogs and Diabetes in cats

In animals, diabetes is most commonly encountered in dogs and cats. Middle-aged animals are most commonly affected. Female dogs are twice as likely to be affected as males, while according to some sources, male cats are also more prone than females. In both species, all breeds may be affected, but some small dog breeds are particularly likely to develop diabetes, such as Miniature Poodles.[94] The symptoms may relate to fluid loss and polyuria, but the course may also be insidious. Diabetic animals are more prone to infections. The long-term complications recognised in humans are much rarer in animals. The principles of treatment (weight loss, oral antidiabetics, subcutaneous insulin) and management of emergencies (e.g. ketoacidosis) are similar to those in humans.[94]

Diabetes, often referred to by doctors as diabetes mellitus, describes a group of metabolic diseases in which the person has high blood glucose (blood sugar), either because insulin production is inadequate, or because the body's cells do not respond properly to insulin, or

Latest Research

both. Patients with high blood sugar will typically experience polyuria (frequent urination), they will become increasingly thirsty (polydipsia) and hungry (polyphagia).

Fast facts on diabetesHere are some key points about diabetes. More detail and supporting information is in the main article.

Diabetes is a long-term condition that causes high blood sugar levels.

In 2013 it was estimated that over 382 million people throughout the world had diabetes (Williams textbook of endocrinology).

Type 1 Diabetes - the body does not produce insulin. Approximately 10% of all diabetes cases are type 1.

Type 2 Diabetes - the body does not produce enough insulin for proper function. Approximately 90% of all cases of diabetes worldwide are of this type.

Gestational Diabetes - this type affects females during pregnancy.

The most common diabetes symptoms include frequent urination, intense thirst and hunger, weight gain, unusual weight loss, fatigue, cuts and bruises that do not heal, male sexual dysfunction, numbness and tingling in hands and feet.

If you have Type 1 and follow a healthy eating plan, do adequate exercise, and take insulin, you can lead a normal life.

Type 2 patients need to eat healthily, be physically active, and test their blood glucose. They may also need to take oral medication, and/or insulin to control blood glucose levels.

As the risk of cardiovascular disease is much higher for a diabetic, it is crucial that blood pressure and cholesterol levels are monitored regularly.

As smoking might have a serious effect on cardiovascular health, diabetics should stop smoking.

Hypoglycemia - low blood glucose - can have a bad effect on the patient. Hyperglycemia - when blood glucose is too high - can also have a bad effect on the patient.

This information hub offers detailed but easy-to-follow information about diabetes. Should you be interested in the latest scientific research on diabetes, please see our diabetes news section.

There are three types of diabetes:

1) Type 1 diabetes

The body does not produce insulin. Some people may refer to this type as insulin-dependent diabetes, juvenile diabetes, or early-onset diabetes. People usually develop type 1 diabetes before their 40th year, often in early adulthood or teenage years.

Type 1 diabetes is nowhere near as common as type 2 diabetes. Approximately 10% of all diabetes cases are type 1.

Patients with type 1 diabetes will need to take insulin injections for the rest of their life. They must also ensure proper blood-glucose levels by carrying out regular blood tests and following a special diet.

Between 2001 and 2009, the prevalence of type 1 diabetes among the under 20s in the USA rose 23%, according to SEARCH for Diabetes in Youth data issued by the CDC (Centers for Disease Control and Prevention). (Link to article)

More information on type 1 diabetes is available in our type 1 diabetes page.

2) Type 2 diabetesThe body does not produce enough insulin for proper function, or the cells in the body do not react to insulin (insulin resistance).

Approximately 90% of all cases of diabetes worldwide are type 2.

Measuring the glucose level in blood

Some people may be able to control their type 2 diabetes symptoms by losing weight, following a healthy diet, doing plenty of exercise, and monitoring their blood glucose levels. However, type 2 diabetes is typically a progressive disease - it gradually gets worse - and the patient will probably end up have to take insulin, usually in tablet form.

Overweight and obese people have a much higher risk of developing type 2 diabetes compared to those with a healthy body weight. People with a lot of visceral fat, also known as central obesity, belly fat, or abdominal obesity, are especially at risk. Being

overweight/obese causes the body to release chemicals that can destabilize the body's cardiovascular and metabolic systems.

Being overweight, physically inactive and eating the wrong foods all contribute to our risk of developing type 2 diabetes. Drinking just one can of (non-diet) soda per day can raise our risk of developing type 2 diabetes by 22%, researchers from Imperial College London reported in the journal Diabetologia. The scientists believe that the impact of sugary soft drinks on diabetes risk may be a direct one, rather than simply an influence on body weight.

The risk of developing type 2 diabetes is also greater as we get older. Experts are not completely sure why, but say that as we age we tend to put on weight and become less physically active. Those with a close relative who had/had type 2 diabetes, people of Middle Eastern, African, or South Asian descent also have a higher risk of developing the disease.

Men whose testosterone levels are low have been found to have a higher risk of developing type 2 diabetes. Researchers from the University of Edinburgh, Scotland, say that low testosterone levels are linked to insulin resistance. (Link to article)

For more information on how type 1 and type 2 diabetes compare, see our article: the difference between type 1 and type 2 diabetes.

More information on type 1 diabetes is available in our type 2 diabetes page.

3) Gestational diabetesThis type affects females during pregnancy. Some women have very high levels of glucose in their blood, and their bodies are unable to produce enough insulin to transport all of the glucose into their cells, resulting in progressively rising levels of glucose.

Diagnosis of gestational diabetes is made during pregnancy.

The majority of gestational diabetes patients can control their diabetes with exercise and diet. Between 10% to 20% of them will need to take some kind of blood-glucose-controlling medications. Undiagnosed or uncontrolled gestational diabetes can raise the risk of complications during childbirth. The baby may be bigger than he/she should be.

Scientists from the National Institutes of Health and Harvard University found that women whose diets before becoming pregnant were high in animal fat and cholesterol had a higher risk for gestational diabetes, compared to their counterparts whose diets were low in cholesterol and animal fats. (Link to article)

Diabetes symptoms

Symptoms of diabetes - by Mikael Häggström

See the next page of our article for a full list of possible diabetes symptoms.

What is prediabetes?The vast majority of patients with type 2 diabetes initially had prediabetes. Their blood glucose levels where higher than normal, but not high enough to merit a diabetes diagnosis. The cells in the body are becoming resistant to insulin.

Studies have indicated that even at the prediabetes stage, some damage to the circulatory system and the heart may already have occurred.

Diabetes is a metabolism disorderDiabetes (diabetes mellitus) is classed as a metabolism disorder. Metabolism refers to the way our bodies use digested food for energy and growth. Most of what we eat is broken down into glucose. Glucose is a form of sugar in the blood - it is the principal source of fuel for our bodies.

When our food is digested, the glucose makes its way into our bloodstream. Our cells use the glucose for energy and growth. However, glucose cannot enter our cells without insulin being present - insulin makes it possible for our cells to take in the glucose.

Insulin is a hormone that is produced by the pancreas. After eating, the pancreas automatically releases an adequate quantity of insulin to move the glucose present in our blood into the cells, as soon as glucose enters the cells blood-glucose levels drop.

A person with diabetes has a condition in which the quantity of glucose in the blood is too elevated (hyperglycemia). This is because the body either does not produce enough insulin, produces no insulin, or has cells that do not respond properly to the insulin the pancreas produces. This results in too much glucose building up in the blood. This excess blood glucose eventually passes out of the body in urine. So, even though the blood has plenty of glucose, the cells are not getting it for their essential energy and growth requirements.

How to determine whether you have diabetes, prediabetes or neitherDoctors can determine whether a patient has a normal metabolism, prediabetes or diabetes in one of three different ways - there are three possible tests:

The A1C test- at least 6.5% means diabetes- between 5.7% and 5.99% means prediabetes- less than 5.7% means normal

The FPG (fasting plasma glucose) test- at least 126 mg/dl means diabetes- between 100 mg/dl and 125.99 mg/dl means prediabetes- less than 100 mg/dl means normalAn abnormal reading following the FPG means the patient has impaired fasting glucose (IFG)

The OGTT (oral glucose tolerance test) - at least 200 mg/dl means diabetes- between 140 and 199.9 mg/dl means prediabetes- less than 140 mg/dl means normalAn abnormal reading following the OGTT means the patient has impaired glucose tolerance (IGT)

Why is it called diabetes mellitus?Diabetes comes from Greek, and it means a "siphon". Aretus the Cappadocian, a Greek physician during the second century A.D., named the condition diabainein. He described patients who were passing too much water (polyuria) - like a siphon. The word became "diabetes" from the English adoption of the Medieval Latin diabetes.

In 1675, Thomas Willis added mellitus to the term, although it is commonly referred to simply as diabetes. Mel in Latin means "honey"; the urine and blood of people with diabetes has excess glucose, and glucose is sweet like honey. Diabetes mellitus could literally mean "siphoning off sweet water".

In ancient China people observed that ants would be attracted to some people's urine, because it was sweet. The term "Sweet Urine Disease" was coined.

Controlling diabetes - treatment is effective and importantAll types of diabetes are treatable. Diabetes type 1 lasts a lifetime, there is no known cure. Type 2 usually lasts a lifetime, however, some people have managed to get rid of their symptoms without medication, through a combination of exercise, diet and body weight control.

Special diets can help sufferers of type 2 diabetes control the condition.

Researchers from the Mayo Clinic Arizona in Scottsdale showed that gastric bypass surgery can reverse type 2 diabetes in a high proportion of patients. They added that within three to five years the disease recurs in approximately 21% of them. Yessica Ramos, MD., said "The recurrence rate was mainly influenced by a longstanding history of Type 2 diabetes before the surgery. This suggests that early surgical intervention in the obese, diabetic population will improve the durability of remission of Type 2 diabetes." (Link to article)

Patients with type 1 are treated with regular insulin injections, as well as a special diet and exercise.

Patients with Type 2 diabetes are usually treated with tablets, exercise and a special diet, but sometimes insulin injections are also required.

If diabetes is not adequately controlled the patient has a significantly higher risk of developing complications.

Complications linked to badly controlled diabetes:Below is a list of possible complications that can be caused by badly controlled diabetes:

Eye complications - glaucoma, cataracts, diabetic retinopathy, and some others.

Foot complications - neuropathy, ulcers, and sometimes gangrene which may require that the foot be amputated

Skin complications - people with diabetes are more susceptible to skin infections and skin disorders

Heart problems - such as ischemic heart disease, when the blood supply to the heart muscle is diminished

Hypertension - common in people with diabetes, which can raise the risk of kidney disease, eye problems, heart attack and stroke

Mental health - uncontrolled diabetes raises the risk of suffering from depression, anxiety and some other mental disorders

Hearing loss - diabetes patients have a higher risk of developing hearing problems

Gum disease - there is a much higher prevalence of gum disease among diabetes patients

Gastroparesis - the muscles of the stomach stop working properly

Ketoacidosis - a combination of ketosis and acidosis; accumulation of ketone bodies and acidity in the blood.

Neuropathy - diabetic neuropathy is a type of nerve damage which can lead to several different problems.

HHNS (Hyperosmolar Hyperglycemic Nonketotic Syndrome) - blood glucose levels shoot up too high, and there are no ketones present in the blood or urine. It is an emergency condition.

Nephropathy - uncontrolled blood pressure can lead to kidney disease

PAD (peripheral arterial disease) - symptoms may include pain in the leg, tingling and sometimes problems walking properly

Stroke - if blood pressure, cholesterol levels, and blood glucose levels are not controlled, the risk of stroke increases significantly

Erectile dysfunction - male impotence.

Infections - people with badly controlled diabetes are much more susceptible to infections

Healing of wounds - cuts and lesions take much longer

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Symptoms Of Diabetes What is Diabetes? Diabetes Symptoms Statistics, Facts & Myths Diagnosis of Diabetes Type 1 Diabetes Type 2 Diabetes Diabetes Complications What is Insulin? Discovery of Insulin Famous Diabetics Treatments for Diabetes Self Monitoring Food Planning Exercise Hypoglycemia Hyperglycemia Taking Insulin Insulin Pumps Latest Research

Statistics from the 2014 USA national diabetes fact sheet from the CDC's National Diabetes Report.

Diabetes Symptoms

29.1 million US children and adults (9.3% of the population) have diabetes. This is a rise from 25.8 million (8.5%) in 2011.

Researchers from the Jefferson School of Population Health (Philadelphia, PA) published a study which estimates that by 2025 there could be 53.1 million people with diabetes.

21 million people have been diagnosed with diabetes (a rise from 18.8 million in 2011).

About 8.1 million people with diabetes have not been diagnosed (a rise from 7 million in 2011). This equates to 27.8% of people with diabetes currently being undiagnosed.

Diagnosed and undiagnosed diabetes among people aged 20 years or older, US, 2012

About 86 million Americans aged 20 years or older have prediabetes.

1.7 million people aged 20 years or more were newly diagnosed with diabetes in 2012.

208,000 (0.25%) people younger than 20 years have diabetes.

Approximately 1 in every 400 kids and teenagers has diabetes.

12.3% of people aged 20+ years have diabetes; a total of 28.9 million individuals.

25.9% of people aged 65+ years have diabetes; a total of 11.2 million people.

13.6% of men have diabetes; a total of 15.5 million people (a rise from 11.8% in 2010).

11.2% of women have diabetes; a total of 13.4 million people (a rise from 10.8 in 2010).

Diabetes in the UKIn the United Kingdom there are about 3.8 million people with diabetes, according to the National Health Service. Diabetes UK, a charity, believes this number will jump to 6.2 million by 2035, and the National Health Service will be spending as much as 17% of its health care budget on diabetes by then.

Diabetes spreads in southeast AsiaDiabetes is rapidly spreading in Southeast Asia as people embrace American fast foods, such as hamburgers, hot dogs, French fries and pizza. More Chinese adults who live in Singapore are dying of heart disease and developing type 2 diabetes than ever before, researchers from the University of Minnesota School of Public Health and the National University of Singapore reported in the journal Circulation.

The authors found that Chinese adults in Singapore who eat American-style junk foods twice a week had a 56% greater risk of dying prematurely form heart disease, while their risk of developing type 2 diabetes rose 27%, compared to their counterparts who "never touched the stuff". There was a 80% higher likelihood of dying from coronary heart disease for those eating fast foods four times per week. (Link to article)

Some facts and myths about diabetesMany presumed "facts" are thrown about in the paper press, magazines and on the internet regarding diabetes; some of them are, in fact, myths. It is important that people with diabetes, pre-diabetes, their loved ones, employers and schools have an accurate picture of the disease. Below are some diabetes myths:

People with diabetes should not exercise - NOT TRUE!! Exercise is important for people with diabetes, as it is for everybody else. Exercise helps manage body weight, improves cardiovascular health, improves mood, helps blood sugar control, and relieves stress. Patients should discuss exercise with their doctor first.

Fat people always develop type 2 diabetes eventually - this is not true. Being overweight or obese raises the risk of becoming diabetic, they are risk factors, but do not mean that an obese person will definitely become diabetic. Many people with type 2 diabetes were never overweight. The majority of overweight people do not develop type 2 diabetes.

Diabetes is a nuisance, but not serious - two thirds of diabetes patients die prematurely from stroke or heart disease. The life expectancy of a person with diabetes is from five to ten years shorter than other people's. Diabetes is a serious disease.

Children can outgrow diabetes - this is not true. Nearly all children with diabetes have type 1; insulin-producing beta cells in the pancreas have been destroyed. These never come back. Children with type 1 diabetes will need to take insulin for the rest of their lives, unless a cure is found one day.

Don't eat too much sugar, you will become diabetic - this is not true. A person with diabetes type 1 developed the disease because their immune system destroyed the insulin-producing beta cells. A diet high in calories, which can make people overweight/obese, raises the risk of developing type 2 diabetes, especially if there is a history of this disease in the family.

I know when my blood sugar levels are high or low - very high or low blood sugar levels may cause some symptoms, such as weakness, fatigue and extreme thirst. However, levels need to be fluctuating a lot for symptoms to be felt. The only way to be sure about your blood sugar levels is to test them regularly. Researchers from the University of Copenhagen, Denmark showed that even very slight rises in blood-glucose levels significantly raise the risk of ischemic heart disease. (Link to article)

Diabetes diets are different from other people's - the diet doctors and specialized nutritionists recommend for diabetes patients are healthy ones; healthy for everybody, including people without the disease. Meals should contain plenty of vegetables, fruit, whole grains, and they should be low in salt and sugar, and saturated or trans fat. Experts say that there is no need to buy special diabetic foods because they offer no special benefit, compared to the healthy things we can buy in most shops.

High blood sugar levels are fine for some, while for others they are a sign of diabetes - high blood-sugar levels are never normal for anybody. Some illnesses, mental stress and steroids can cause temporary hikes in blood sugar levels in people without diabetes. Anybody with higher-than-normal blood sugar levels or sugar in their urine should be checked for diabetes by a health care professional.

Diabetics cannot eat bread, potatoes or pasta - people with diabetes can eat starchy foods. However, they must keep an eye on the size of the portions. Whole grain starchy foods are better, as is the case for people without diabetes.

One person can transmit diabetes to another person - NOT TRUE. Just like a broken leg is not infectious or contagious. A parent may pass on, through their genes to their offspring, a higher susceptibility to developing the disease.

Only older people develop type 2 diabetes - things are changing. A growing number of children and teenagers are developing type 2 diabetes. Experts say that this is linked to the explosion in childhood obesity rates, poor diet, and physical inactivity.

I have to go on insulin, this must mean my diabetes is severe - people take insulin when diet alone or diet with oral or non-insulin injectable diabetes drugs do not provide good-enough diabetes control, that's all. Insulin helps diabetes control. It does not usually have anything to do with the severity of the disease.

If you have diabetes you cannot eat chocolates or sweets - people with diabetes can eat chocolates and sweets if they combine them with exercise or eat them as part of a healthy meal.

Diabetes patients are more susceptible to colds and illnesses in general - a person with diabetes with good diabetes control is no more likely to become ill with a cold or something else than other people. However, when a diabetic catches a cold, their diabetes becomes harder to control, so they have a higher risk of complications.

Accurate tests are available to doctors to definitively confirm a diagnosis of diabetes.

Before tests are conducted, a diagnosis may be suspected when patients report certain symptoms. Doctors will evaluate these symptoms by asking questions about the patient's medical history.1

Diagnosis of Diabetes

Doctors may also carry out a physical examination, including checks for complications that could have already developed - examining the feet for changes in sensation, for example.2

Testing can be part of routine screening for people at risk of the disease, who may show up as having prediabetes. The US Department of Health and Human Services recommends diabetes testing for anyone overweight at the age of 45 years and over, alongside anyone under the age of 45 with one or more of the following risk factors:2,3

Hypertension (high blood pressure)

High cholesterol

History of diabetes in the family

African-American, Asian-American, Latino/Hispanic-American, Native American or Pacific Islander background

History of gestational diabetes (diabetes during pregnancy) or delivering a baby over 9 lbs.

Blood tests for diabetes diagnosis

Diagnoses of diabetes are confirmed through 1 of 3 types of blood test.

One of three blood tests can be used to confirm a diagnosis of diabetes:2-5

Fasting plasma glucose (FPG) levels - a blood test after 8 hours of no eating

Glycosylated hemoglobin (HbA1c) - to measure a marker of the average blood glucose level over the past 2-3 months

Oral glucose tolerance testing (OGTT) - a test used less frequently that measures levels before and 2 hours after consuming a sweet drink (concentrated glucose solution).

Glycosylated hemoglobin is often abbreviated to A1C, and this blood test is also used in the monitoring of diabetes management.2,5

To make an initial diagnosis, an HbA1c reading must be 6.5% or higher. An A1C result between 5.7% and 6.4% indicates prediabetes and a risk of type 2 diabetes.2,5,6

The HbA1c is the preferred blood test for diagnosis because - while it is more expensive than the FPG test - it has advantages, including:5

Urine tests for diabetes were once common but are no longer considered reliable.

Greater convenience (no need for fasting)

Less day-to-day variation during stress and illness.

When the fasting plasma glucose test is used to confirm symptoms, diabetes is diagnosed at levels equal to or above 126 mg/dL (7.0 mmol/L).7

For oral glucose tolerance testing, the plasma glucose levels after 2 hours need to be equal to or above 200 mg/dL (11.1 mmol/L) for a diabetes diagnosis.7

Another blood test is the random plasma glucose test - taken regardless of time and eating - which diagnoses diabetes if the level is at least 200 mg/dL (11.1 mmol/L).7

Unless the clinical picture is clear, a positive blood test should also be repeated to rule out laboratory error.

Urine tests for diabetes diagnosisUrine tests are no longer used to make a diagnosis of diabetes, although they were once common. Blood tests are used instead because urine tests are not sensitive or specific enough and offer only a crude indication of high blood sugar levels.2,8

A urine sample may be used, however, to test for ketones, particularly in people with type 1 diabetes who exhibit certain symptoms. Here, the test can pick up ketoacidosis, a complication of diabetes.2,6,8

Type 1 Diabetes

While type 2 diabetes is often preventable, type 1 diabetes mellitus is not.1 Type 1 diabetes is an autoimmune disease in which the immune system destroys cells in the pancreas.

Typically, the disease first appears in childhood or early adulthood. Type 1 diabetes used to be known as juvenile-onset diabetes or insulin-dependent diabetes mellitus (IDDM), but the disease can have an onset at any age.2

Type 1 diabetes makes up around 5% of all cases of diabetes.3,4

What is type 1 diabetes?

Type 1 diabetes usually first appears in childhood or adolescence.

In type 1 diabetes, the pancreas is unable to produce any insulin, the hormone that controls blood sugar levels.2,3

Insulin production becomes inadequate for the control of blood glucose levels due to the gradual destruction of beta cells in the pancreas. This destruction progresses without notice

over time until the mass of these cells decreases to the extent that the amount of insulin produced is insufficient.2

Type 1 diabetes typically appears in childhood or adolescence, but its onset is also possible in adulthood.2

When it develops later in life, type 1 diabetes can be mistaken initially for type 2 diabetes. Correctly diagnosed, it is known as latent autoimmune diabetes of adulthood.2

Causes of type 1 diabetesThe gradual destruction of beta cells in the pancreas that eventually results in the onset of type 1 diabetes is the result of autoimmune destruction. The immune system turning against the body's own cells is possibly triggered by an environmental factor exposed to people who have a genetic susceptibility.2

Although the mechanisms of type 1 diabetes etiology are unclear, they are thought to involve the interaction of multiple factors:2

Susceptibility genes - some of which are carried by over 90% of patients with type 1 diabetes. Some populations - Scandinavians and Sardinians, for example - are more likely to have susceptibility genes

Autoantigens - proteins thought to be released or exposed during normal pancreas beta cell turnover or injury such as that caused by infection. The autoantigens activate an immune response resulting in beta cell destruction

Viruses - coxsackievirus, rubella virus, cytomegalovirus, Epstein-Barr virus and retroviruses are among those that have been linked to type 1 diabetes

Diet - infant exposure to dairy products, high nitrates in drinking water and low vitamin D intake have also been linked to the development of type 1 diabetes.

Life with type 1 diabetes

Health care professionals usually teach people with type 1 diabetes to self-manage the condition.

Type 1 diabetes always requires insulin treatment and an insulin pump or daily injections will be a lifelong requirement to keep blood sugar levels under control. The condition used to be known as insulin-dependent diabetes.3

After the diagnosis of type 1 diabetes, health care providers will help patients learn how to self-monitor via finger stick testing, the signs of hypoglycemia, hyperglycemia and other diabetic complications. Most patients will also be taught how to adjust their insulin doses.2

As with other forms of diabetes, nutrition and physical activity and exercise are important elements of the lifestyle management of the disease.

Type 2 Diabetes

Type 2 is the most common form of diabetes, accounting for over 90% of all diabetes cases.1,2

The number of adults diagnosed with diabetes in the US has risen significantly in the past 30 years, almost quadrupling from 5.5 million cases in 1980 to 21.3 million in 2012.1

Type 2 diabetes used to be known as adult-onset diabetes and noninsulin-dependent diabetes mellitus (NIDDM), but the disease can have an onset at any age, increasingly including childhood.2

What is type 2 diabetes?Type 2 diabetes mellitus most commonly develops in adulthood and is more likely to occur in people who are overweight and physically inactive.3

Unlike type 1 diabetes which currently cannot be prevented, many of the risk factors for type 2 diabetes can be modified. For many people, therefore, it is possible to prevent the condition.4

The International Diabetes Foundation highlight four symptoms that signal the need for diabetes testing:5

Frequent urination

Weight loss

Lack of energy

Excessive thirst.

To learn more, visit the Knowledge Center articles about symptoms or diagnosis.

Causes of type 2 diabetesInsulin resistance is usually the precursor to type 2 diabetes - a condition in which more insulin than usual is needed for glucose to enter cells.3 Insulin resistance in the liver results in more glucose production while resistance in peripheral tissues means glucose uptake is impaired.2

Obesity can lead to insulin resistance - often the precursor to the development of type 2 diabetes.

The impairment stimulates the pancreas to make more insulin but eventually the pancreas is unable to make enough to prevent blood sugar levels from rising too high.3

Genetics plays a part in type 2 diabetes - relatives of people with the disease are at a higher risk, and the prevalence of the condition is higher in particular among Native Americans, Hispanic and Asian people.2

Obesity and weight gain are important factors that lead to insulin resistance and type 2 diabetes, with genetics, diet, exercise and lifestyle all playing a part. Body fat has hormonal effects on the effect of insulin and glucose metabolism.2

Once type 2 diabetes has been diagnosed, health care providers can help patients with a program of education and monitoring, including how to spot the signs of hypoglycemia, hyperglycemia and other diabetic complications.2

As with other forms of diabetes, nutrition and physical activity and exercise are important elements of the lifestyle management of the condition.

For more information on how type 1 and type 2 diabetes compare, read our article: the difference between type 1 and type 2 diabetes.

Even when diabetes is well controlled, it raises the risk of other conditions such as heart disease, and poorly controlled diabetes can lead to serious complications.1-3

The good news is that diabetes prevention has greatly improved, leading to a drop in the rates of five major complications - including death - from 1990-2010 in the US.4

Causes of diabetes complications

Diabetes Complications

High blood glucose levels are damaging to blood vessels and can increase the likelihood of them narrowing through atherosclerosis. This damage also leads to poor supply of blood to nerves.1-3

Poorly controlled hyperglycemia persisting for years can lead to complications affecting small blood vessels (microvascular complications), large blood vessels (macrovascular complications) or both.2

The process by which vascular disease develops is complex and occurs via numerous pathways that scientists continue to investigate.5

What complications are caused by diabetes?Microvascular complications - those resulting from damage to small blood vessels - are the most common complications of diabetes and include:2

Retinopathy - disease of the eye

Nephropathy - disease of the kidneys

Neuropathy - disease of the nerves.

Macrovascular complications - those resulting from damage to large blood vessels - include:2

Angina pectoris and heart attack

Transient ischemic attacks and strokes

Peripheral arterial disease.

Diabetic retinopathy

People with diabetes should go for regular professional eye checks.

Diabetic retinopathy is an eye complication caused by disease of the tiny blood vessels supplying the retina (the light-sensitive back of the eye).2,3

Early detection and preventive action are important. As symptoms do not appear before damage is done, anyone with diabetes - whether type 1 or type 2 - should have their eyes regularly checked by an optometrist or ophthalmologist.2,3,6

Most people with diabetic retinopathy do not lose their vision, but blindness is nonetheless a risk. The key to prevention is tight control over blood sugar levels. Interventions are also available for diabetic retinopathy, such as laser photocoagulation.2,6

Diabetic nephropathyDiabetic nephropathy - kidney or renal disease - is another complication caused by damage to small blood vessels.2

Diabetes is the cause of most cases of the most serious kidney disease - end-stage renal disease.1 Nephropathy can also appear at other stages, from renal insufficiency through to chronic renal failure. There is a progressive decline in kidney function in terms of the glomerular filtration rate.2

Nephropathy is diagnosed by urine test and the primary treatment - as with other diabetes complications - is tight control of blood sugar levels. In addition, blood pressure treatment with drugs may be needed.2

Diabetic neuropathyDiabetic neuropathy - a disease of nerves - is also a complication caused by damage to small blood vessels. In this case, it involves capillaries supplying nerves.2

Foot complications

Diabetes can cause nerve damage in the feet. Wounds can go unnoticed and fail to heal properly.

Complications affecting the foot - often referred to as "diabetic foot" - result from neuropathy, nerve damage that causes tingling sensations, burning or stinging pain, weakness or loss of feeling.2,6 The nerves become damaged due to restricted blood supply.2

The phenomenon can also affect the hands, but it is the feet that are most commonly affected. Because of the loss of sensation for heat, cold or pain, and a lack of attention given to the feet, they are at risk from injury, wounds, blisters or ulcers going unnoticed. If left unnoticed, this condition can lead to infection and even gangrene and potential amputation.2,3,7

Nerve damage leads to skin changes, making the foot dry and prone to cracking or peeling.2,7 Poor circulation to the feet caused by vessel narrowing can also mean that any infections or wounds heal less readily.7

The key to preventing foot complications is to monitor the feet so that problems are spotted at the first opportunity. Seeking medical attention for any problems is important, as is getting the feet checked by a health care professional, such as a podiatrist, at least annually.2 Other practical measures include:3

Keeping the feet clean and dry

Ensuring the nails are well-maintained

Wearing socks and shoes that fit comfortably and do not rub or squeeze the feet.

Macrovascular complicationsDisease of the large blood vessels caused by diabetes can lead to angina, transient ischemic attacks or stroke, heart attack and peripheral arterial disease. Alongside microvascular disease, macrovascular disease also contributes to the risk of the heart disease cardiomyopathy.2

Screening, history and physical examination diagnose macrovascular disease, and treatment includes tight control of blood sugar levels as well as lipid- and blood pressure-lowering therapies. Other strategies include smoking cessation, aspirin and drugs known as ACE inhibitors.2

Adults with diabetes are two-to-four times more likely to have heart disease or a stroke than those without diabetes. A number of risk factors in people with diabetes contribute to macrovascular complications:1

High blood pressure

Abnormal cholesterol and high triglyceride levels

Obesity

Lack of physical activity

Smoking.

Prevention of diabetes complicationsAll the potential complications of diabetes can be prevented or controlled with tight glycemic control, which means keeping HbA1C levels below 7%.2

Measures to keep control of glucose levels, in addition to drugs or insulin treatment, include exercise and diet. Additionally, keeping control of blood pressure and lipid levels helps to prevent complications of diabetes.2

As discussed above, close monitoring of health so that potential complications are spotted at the first opportunity is also a preventive measure, including specific checks for the eyes and feet.

The discovery of insulin was one of the most dramatic and important milestones in medicine - a Nobel Prize-winning moment in science.

Witnesses to the first people ever to be treated with insulin saw "one of the genuine miracles of modern medicine," says the author of a book charting its discovery.1

Discovery of Insulin

Starved and sometimes comatose patients with diabetes would return to life after receiving insulin.

But how and when was the discovery made, and who made it?

How and when was insulin discovered?The discovery of insulin did not come out of the blue; it was made on the back of a growing understanding of diabetes mellitus during the nineteenth century.

Experiments involving the pancreas were key to the discovery of insulin. The beta cells of the pancreas that produce insulin were discovered in 1869.

Diabetes itself had been understood by its symptoms as far back as the 1600s - when it was described as the "pissing evile" - and the urination and thirst associated with it had been recognized thousands of years before.

A feared and usually deadly disease, doctors in the nineteenth century knew that sugar worsened diabetes and that limited help could be given by dietary restriction of sugar. But if that helped, it also caused death from starvation.

Scientists observed the damaged pancreases of people who died with diabetes. In 1869, a German medical student found clusters of cells in the pancreas that would go on to be named after him.

Paul Langerhans had discovered the beta cells that produce insulin.

Other work in animals then showed that carbohydrate metabolism was impossible once the pancreas was removed - the amount of sugar in the blood and urine rose sharply, and death from diabetes soon followed.

In 1889, Oscar Minkowski and Joseph von Mering removed a dog's pancreas to study its effects on digestion. They found sugar in the dog's urine after flies were noticed feeding off it. In humans, doctors would once have diagnosed the condition by tasting the urine.

But as for the discovery of the "active ingredient" of the pancreas, numerous scientists followed the work of Minkowski and von Mering in their attempts to extract it.

Between 1914 and 1916, it was the Romanian physiologist Nicolas C. Paulescu who first extracted a pancreatic antidiabetic agent that treated dogs - but his experiments would be overlooked in favor of work by other scientists.

Banting, Best, Collip and MacleodIt was in 1921 that Canadian physician Frederick Banting and medical student Charles H. Best would be credited with discovering the hormone insulin in the pancreatic extracts of dogs.

Banting and Best injected the hormone into a dog and found that it lowered high blood glucose levels to normal. They then perfected their experiments to the point of grinding up and filtering a dog's surgically tied pancreas, isolating a substance called "isletin."

The pair then developed insulin for human treatment with the help of Canadian chemist James B. Collip and Scottish physiologist J.J.R. Macleod.

Macleod had been impressed with Banting and Best's work but wanted a retrial of the evidence. He provided pancreases from cows to make the extract which was named "insulin," and the procedures were repeated. Collip's role was to help with purifying the insulin to be used for testing on humans.

Ultimately, the first medical success was with a boy with type 1 diabetes - 14-year-old Leonard Thompson - who was successfully treated in 1922. Close to death before treatment, Leonard bounced back to life with the insulin.

The news rapidly spread beyond Canada, and in 1923 the Nobel Committee decided to award Banting and Macleod the Nobel Prize in Physiology or Medicine.

Type 2 diabetes has a number of drug treatment options to be taken by mouth known as oral antihyperglycemic drugs or oral hypoglycemic drugs.

Oral diabetes drugs are usually reserved for use only after lifestyle measures have been unsuccessful in lowering glucose levels to the target of an HbA1c below 7.0%, achieved through an average glucose reading of around 8.3-8.9 mmol/L (around 150-160 mg/dL).1-3

The lifestyle measures that are critical to type 2 diabetes management are diet and exercise, and these remain an important part of treatment when pills are added.2,3

People with type 1 diabetes cannot use oral pills for treatment, and must instead take insulin.

Treatment for Diabetes

How do oral drugs lower glucose levels?

Metformin is the most widely used oral antihyperglycemic drug and reduces the amount of glucose released by the liver into the bloodstream.

Oral antihyperglycemic drugs have three modes of action to reduce blood glucose levels:3

Secretagogues enhance insulin secretion by the pancreas

Sensitizers increase the sensitivity of the peripheral tissues to insulin

Inhibitors impair gastrointestinal absorption of glucose.

Each class of antihyperglycemic drug has a different adverse event or safety profile, and side effects are the main consideration when it comes to choosing a medication.

Possible side effects range from weight gain, through gastrointestinal ones such as diarrhea, to pancreatitis and more serious problems. Hypoglycemia is also a possible adverse event.2

What oral drugs are available for type 2 diabetes?No one particular choice of oral hypoglycemic is considered the most effective form of treatment - the decision over which drug to use is instead based on:1-3

Consideration of the adverse side effects

Convenience and overall tolerability

Personal preference.

In reality, weighing up each drug is something to do in partnership with a prescriber - guidelines partly drawn up by the American Diabetes Association list a great number of advantages and disadvantages for each of the available drug treatments, including the consideration of cost.2

The use of a single drug can be escalated to combination therapy with a second drug in an effort to improve glycemic control.1,2

Metformin is usually the first treatment offered, however, and it is the most widely used oral antihyperglycemic. Metformin is a sensitizer in the class known as biguanides; it works by reducing the amount of glucose released by the liver into the bloodstream and increasing cellular response to insulin. A metformin pill is usually taken twice a day.1-4

This drug is a low-cost antihyperglycemic with mild side effects that can include diarrhea and abdominal cramping. Metformin is not associated with weight gain or hypoglycemia.2-4

Sulphonylureas are secretagogues that increase pancreatic insulin secretion. There are several drug names in this class, including:1,3

Chlorpropamide

Glimepiride

Glipizide

Glyburide.

Again, the choice of drug is an individual one. In the case of sulphonylureas, the choice depends on daily dosing and the level of side effects. These drugs are associated with weight gain and hypoglycemia.2

Glitazones (also known as thiazolidinediones) are sensitizers - they increase the effect of insulin in the muscle and fat and reduce glucose production by the liver.1-3

Two glitazones are available: pioglitazone and rosiglitazone. These drugs can have the side effects of weight gain or swelling and are associated with increased risks of heart disease and stroke, bladder cancer and fractures.

In the UK, rosiglitazone was withdrawn from the market over concerns about adverse events.4 In 2015, it remains available in the US, with information on its safety provided by the US Food and Drug Administration (FDA).

Alpha-glucosidase inhibitors are intestinal enzyme inhibitors that block the breakdown of carbohydrates into glucose, reducing the amount absorbed in the gut.1,3,4

Available as acarbose and miglitol, they are not usually tried as first-line drugs because of common side effects of flatulence, diarrhea and bloating, although these may reduce over time.1,3,4

Dipeptidyl peptidase-4 (DPP4) inhibitors include alogliptin, linagliptin, saxagliptin and sitagliptin.1

Also known as gliptins, DPP4 inhibitors have a number of effects, including stimulating pancreatic insulin (by preventing the breakdown of the hormone GLP-1). They may also help with weight loss through an effect on appetite.1-4

These drugs do not increase the risk of hypoglycemia. Mild possible side effects are nausea and vomiting.1-4

Sodium-glucose co-transporter 2 (SGLT2) inhibitors include canagliflozin and dapagliflozin. They work by inhibiting the reabsorption of glucose in the kidneys, causing glucose to be excreted in the urine (glycosuria).1,3

SGLT2s may also cause modest weight loss. Side effects include urinary infection.1,3

Meglitinides include repaglinide and nateglinide. They stimulate the release of insulin by the pancreas. Meglitinides are associated with a higher chance of hypoglycemia and must be taken with meals three times a day. As a result, these drugs are less commonly used

Self Monitoring

Tight control of blood sugar levels is difficult to achieve. Levels can fall too low even with the best adherence to demanding daily self-monitoring schedules.

The proportion of people in the US with a diagnosis of diabetes who undertake self-monitoring of glucose has risen dramatically - from 36% in 1994 to 64% in 2010.1

All patients newly diagnosed with type 1 diabetes will receive training on how to do their blood sampling and how to act on readings. Increasing numbers of people with type 2 diabetes - even those who do not need insulin treatment - are also recommended to self-monitor their blood glucose levels.

What is blood glucose self-monitoring?

Self-monitoring requires a drop of blood and allows patients to improve their understanding of their blood glucose levels.

The aim of self-monitoring is to collect detailed information about blood glucose levels over time at multiple points. It helps maintain constant glucose levels and prevent hypoglycemia, and allows the following to be scheduled accordingly:2-4

The treatment regime/insulin doses

Dietary intake

Physical activity.

Such glycemic control is important in the prevention of the long-term complications of diabetes.4,5

In addition to monitoring diabetes treatment effects and identifying blood sugar highs and lows, self-monitoring is a strategy that guides overall treatment goals. Self-monitoring also

gives insight into how diet, exercise and other factors, such as illness and stress, affect blood sugar levels.5,6

Self-monitoring helps patients improve their knowledge of glucose levels and the effects of different behaviors on their blood glucose.5,6

Patients on glucose-lowering drugs can take their self-monitoring records to their health care provider, allowing them to measure prescriptions accordingly and recommend any adjustments to diet and exercise.4

Strict glycemic control in type 1 diabetes is difficult to achieve - even with good education on self-monitoring, the most frequent measurement does not give enough information to avoid hypoglycemia.7

Who should self-monitor blood glucose?It was previously only people with insulin-treated diabetes - type 1 in particular - who would be recommended to self-monitor their blood glucose levels.8

International guidelines now state that there is enough evidence for the benefit of glycemic control to recommend self-monitoring to anyone with diabetes, including those with type 2 diabetes who do not need insulin treatment, as long as there is sufficient healthcare support. Adequate support entails the following:4,8

The monitoring is incorporated into an education program to promote appropriate treatment adjustments according to blood glucose values

There is shared management with health care providers to provide a clear set of instructions for acting on results.

The type of diabetes determines how regularly self-measurement is needed. Type 1 diabetes demands several daily measurements whereas insulin-treated type 2 diabetes needs only around two a day. If no insulin treatment is needed, less than daily measurement may be sufficient.5

Target blood glucose levelsThe overall goal of glycemic control for adults with diabetes has been set by the American Diabetes Association, whose guidance is followed by health care providers. It states:9

The HbA1c level (a marker of average glucose levels over recent months) should be lowered to 7% to reduce the risk of diabetes complications

If possible, and as long as hypoglycemia can be avoided, some individuals may be able to target an HbA1c of 6.5%.

Less ambitious HbA1c targets (such as getting below 8%) are appropriate for some patients, including those who have any of the following:9

History of severe hypoglycemia

Limited life expectancy

Advanced diabetes complications

Extensive coexisting conditions.

Less stringent targets may also be appropriate for people with long-standing diabetes who find targets difficult in spite of disease management strategies.9

The 7% HbA1c level informs the equivalent self-monitoring targets that patients can aim for (and again, less ambitious targets are appropriate for some patients):9

Before meals (preprandial) - 70-130 mg/dL (3.9-7.2 mmol/L)

After meals (postprandial, 1-2 hours after start of meal) - less than 180 mg/dL (<10.0 mmol/L).

How is a blood glucose monitor used?A glucose meter electronically reads a small sample of blood on a test strip. The blood is usually drawn by a skin prick at the tip of a finger.5

Over 20 types of glucose meter are commercially available, varying in size, the amount of blood needed and electronic memory and analysis features. While some enable graphs to be computed, for many it is up to the user to keep meticulous records including details of times, diet and exercise.3,5

Practical tips for blood glucose monitoring include:4

Self-monitoring of type 1 diabetes demands between four and eight finger-prick measurements every day.

Handle the meter and test strips with clean, dry hands

Use the test strips specified for the meter and keep these in the original container

Use a test strip only once and discard

Strips can be calibrated with the meter for accuracy, and some meters require coding with each new canister of strips

Check for expiration dates

Keep in a cool, dry place

Take the meter to office visits for checks by providers.

Practical steps are also needed in preparation of the skin prick for a blood sample. The skin site should be cleaned with warm, soapy water and dried, or an alcohol pad can be used. Otherwise - if food has been handled recently, for example - false readings can occur.2,4

The lancet sizes vary and can be adjusted to prick the skin and produce the different amounts of blood needed by various meters. Thinner and sharper lancets are typically the most comfortable. Lancets should not be reused after single use.4

To reduce pain, the sides of the finger can be used and fingers can be rotated, including any of the five digits instead of the index finger or thumb.4

While the most accurate measurements are enabled by the use of the fingertips or outer palm, some meters allow the use of other sites such as the upper arms and thighs.4

When should glucose self-monitoring tests be done?Individual cases of diabetes require different levels of blood glucose monitoring. The frequency of testing can change for an individual as well; the frequency may need to be intensified in the event of changes to medications, stress levels, diet or activity levels.2

Examples of the sort of information that can be provided by meter readings include checking oral medicines or long-acting insulins through the use of nighttime fasting blood glucose (FBG) readings, taken at around 3 or 4am.2

Test results from before eating can help to guide changes to meals or medicines, and those obtained 1-2 hours following a meal are informative when learning how blood sugar levels are affected by food.2

Tests at bedtime also help inform adjustments to diet or medications.2

Real-time continuous glucose monitoring

Continuous glucose monitoring overcomes the problem of taking numerous manual daytime readings from skin pricks.

People with type 1 diabetes typically do between four and eight finger-prick measurements each day, and rarely monitor nighttime blood glucose levels.5,7

Such self-monitoring can lead to rapid changes in blood glucose known as excursions, including postprandial hyperglycemia, asymptomatic hypoglycemia and fluctuations overnight.7

Real-time continuous glucose monitoring has been shown to be more effective than self blood glucose measurement in reducing HbA1c in type 1 diabetes because it provides detailed information on glucose patterns and trends.7

The major factor crucial to the success of the devices is motivation and compliance of the user.7

The available continuous monitors - some of which are combined with insulin pumps - consist of an electrochemical sensor placed under the skin and replaced every 3-7 days

Food Planning

Alongside exercise, a healthy diet is an important element of the lifestyle management of diabetes, as well as being preventive against the onset of type 2 diabetes.

Maintaining a good diet is also a vital part of keeping tight control of blood sugar levels, itself important for minimizing the risk of diabetes complications.1

The good news for people living with diabetes is that the condition does not preclude any particular type of food or require an unusual diet - the goal is much the same as it would be for anyone wishing to eat a healthy, balanced diet.2

What diet is best for diabetes?

Choose skim milk and low-fat dairy products to help reduce fat intake.

Having diabetes does not involve any particularly difficult dietary demands, and while sugary foods obviously affect blood glucose levels, the diet does not have to be completely sugar-free.2

Dietary concerns vary slightly for people with different types of diabetes. For people with type 1 diabetes, diet is about managing fluctuations in blood glucose levels while for people with type 2 diabetes, it is about losing weight and restricting calorie intake.3

For people with type 1 diabetes, the timing of meals is particularly important in terms of glycemic control and in relation to the effects of insulin injection.3

In general, however, a healthy, balanced diet is all that is needed, and the benefits are not confined to good diabetes management - they also mean good heart health.2,4 A healthy diet typically includes a variety of fruits and vegetables, whole grains, low-fat dairy products, skinless poultry and fish, nuts and legumes and non-tropical vegetable oils.4

The following are some general dietary tips for a healthy lifestyle:2-5

Eat regularly - avoid the effects on glucose levels of skipping meals or having delayed meals because of work or long journeys (take healthy snacks with you)

Eat vegetables and fruits and eat them in place of high-calorie foods - a variety of fresh, frozen and canned is good, but avoid high-calorie sauces and food containing added salt or sugar

Whole grains high in fiber are recommended as a healthy source of carbohydrate

Try drinking water or tea and coffee instead of sugary drinks and avoid adding sugar to hot drinks.

Eat pulses, a low-fat starchy source of protein and fiber, such as beans, lentils, chickpeas and garden peas

Reduce intake of saturated and trans fats by having poultry and fish without the skin and cooked, for example, under the grill, rather than fried

Take a similar approach to cooking red meat while reducing intake and looking for the leanest cuts

Eat fish twice a week or more, but avoid batters and frying - go for oily fish such as salmon, mackerel, sardine, trout and herring, which are rich sources of omega-3

Avoid partially hydrogenated vegetable oils and limit saturated fat and trans fat - replace them with monounsaturated and polyunsaturated fats

Dairy awareness helps reduce fat intake - select skim (fat-free) milk and low-fat (1%) dairy products, reduce consumption of cheese and butter and swap out creamy sauces for tomato-based ones

Cut back on sugar by avoiding added sugars in drinks and foods - have tea and coffee without sugar, avoid fruit that is canned in syrup and pay attention to food labels

Cut back on salt - prepare foods at home with little or no salt and avoid foods with high sodium such as processed foods

Cut back on portion sizes - be wary of amounts consumed when eating out

Be wary of "diabetic" foods - they are of no particular benefit and can be expensive

Drink alcohol only in moderation - as a guide, no more than one drink a day for women and no more than two for men.

Professional help with lifestyle changes for diabetesIn the US, the Community Preventive Services Task Force run diabetes prevention programs that help with improving diet for people at risk of, or newly diagnosed with type 2 diabetes. The programs may include:6

Goals toward weight loss

Individual and group education sessions on diet and exercise

Meetings with diet and exercise counselors

Individually designed diet and exercise plans.

Participants in the national diabetes prevention program have access to a lifestyle coach to learn more about healthy eating and exercise.6

Obesity, diabetes and dietObesity is a risk factor for type 2 diabetes, and obesity in people who already have diabetes results in poor control of blood sugar, blood pressure and cholesterol levels.6

Another concern with being overweight or having obesity is that it can worsen many of the complications of diabetes.6

Weight loss can be achieved by following the recommendations above and restricting the intake of calories

Alongside diet, exercise is an important element of the lifestyle management of diabetes, as well as being preventive against the onset of type 2 diabetes.

Exercise need not be hard work and can be effective if done in a way that is enjoyable. Staying active simply through outdoor activities such as walking and gardening or through favorite games such as tennis is a valid approach.1

Before embarking on any new exercise activity, it is worth discussing it first with a health care professional, especially if there are any diabetes complications present. Starting slowly is also important in with any new activity.1,2

Why is exercise important in diabetes?Two main factors are behind the need to maintain regular physical exercise:3

Exercise helps with weight loss

Exercise is good for heart health, helping to prevent diabetes complications.

Physical activity also raises the use of glucose by muscles and so can lower blood glucose levels. Regular activity can also help reduce the amount of insulin needed to control blood sugar levels by improving the body's insulin efficiency.4

What exercise is best with diabetes?

People with diabetes should increase their level of exercise gently, building up to a maximum level that remains comfortable.3

Although some experts consider aerobic exercise to be best, lower-intensity exercise such as swimming can be just as beneficial.

In the US, the Community Preventive Services Task Force run diabetes prevention programs that help with increasing exercise and improving diet for people at risk of, or newly diagnosed with type 2 diabetes. These programs may include:5

Goals toward weight loss

Individual and group education sessions on diet and exercise

Meetings with diet and exercise counselors

Individually designed diet and exercise plans.

Some experts consider aerobic exercise to be best, in which the heart rate and rate of breathing go up considerably.3 Lower-intensity exercise such as swimming is as much of an option for keeping healthy as higher-impact exercise such as running, however.

The American Heart Association has an easy-to-remember general recommendation for exercise goals - take part in 30 minutes of moderate exercise on 5 days of the week, reaching a total of 150 minutes a week. In addition, on 2 days a week, some moderate-to-high-intensity muscle strengthening activity is suggested.6

More intensive goals are recommended for lowering certain risk factors, but individuals with diabetes should seek help with tailoring their exercise to meet their personal circumstances and goals.3

Exercise and glucose controlPhysical activity increases the use of glucose, so patients who experience symptoms of hypoglycemia during exercise need to monitor their blood glucose and increase carbohydrate intake or lower their insulin dose accordingly. Glucose levels need to be just above normal ahead of starting an activity.3

If hypoglycemia occurs during vigorous exercise, it may be necessary to ingest carbohydrates - around 5-15 grams of a simple sugar such as sucrose, for example.3

What's the best exercise for type 2 diabetes?This video, by YourUpdate, discusses a randomized control trial that found that both aerobic exercise and resistance exercise improved blood sugar control in people with type 2 diabetes.

Hypoglycemia

Hypoglycemia is a complication of diabetes treatment whereby blood sugar levels fall too low.

Strict glycemic control is important for reducing the risk of other serious complications but it also raises the risk of hypoglycemia.1

Hypoglycemia is an iatrogenic problem - a condition brought on by medical intervention. Hypoglycemia is the most common complication of diabetes treatment with insulin.1

Causes of hypoglycemiaHypoglycemia occurs when blood glucose levels fall below 4 mmol/L (72mg/dL).2,3

The symptoms of hypoglycemia are ultimately caused by glucose deprivation of the nerves. There are two types of hypoglycemia symptoms: neurogenic and neuroglycopenic symptoms.4

Neurogenic symptoms arise from the perception of physiological changes caused by the involuntary nervous system's response to hypoglycemia, while neuroglycopenic symptoms result from glucose deprivation of the brain.4

Symptoms of hypoglycemiaHypoglycemia can be dangerous and its onset can be quick. As a result, it is important to learn how to recognize its symptoms.1

Mild or moderate hypoglycemia can lead to symptoms including the following:1,2,4

Headache

Sweating, chills or clamminess

Heart palpitations

Lightheadedness or dizziness

Blurred vision

Agitation.

Other symptoms include:

Trembling or shakiness

Anxiety

Hunger

Paresthesias such as tingling or numbness in the lips or tongue

Looking pale.

The neuroglycopenic symptoms can be the most severe and result from glucose deprivation of the brain. These symptoms include:1,3,4

Confusion

A sensation of warmth

Weakness or fatigue

Severe cognitive failure

Seizure or convulsions

Coma.

Treatments for hypoglycemiaAn episode of hypoglycemia can be treated quickly and effectively with 15-20 grams of glucose.1-3

A tablespoon of honey can be used as fast-acting for an episode of hypoglycemia.

If glucose is not available, other fast-acting, simple carbohydrate alternatives include a tablespoon of honey, sweets such as jelly beans and 250ml of a non-diet soft drink or fruit juice .2,3

Around 15 minutes after administering the initial treatment, the patient should check their blood glucose level if possible. If it is not over 4.4 mmol/L (80 mg/dL), another 15 grams of glucose should be taken.1

In cases where there is unconsciousness or an inability to swallow, trained health care professionals or carers can treat hypoglycemia by injecting either one milligram of glucagon (which causes the liver to release glucose) under the skin or into the muscles, or 50 mL of a 50% dextrose solution (25 grams) into a vein.1,2

An emergency ambulance should be called for a case involving loss of consciousness or if treatment is not available. Further infusion may follow glucagon or dextrose injection.1

What is hypoglycemia unawareness?Hypoglycemia unawareness is the inability to perceive the symptoms of hypoglycemia, resulting in a loss of warning symptoms for low blood glucose levels.4,6

People who have had type 1 diabetes for a long time may develop hypoglycemia unawareness.1,2 The condition is more common in cases of type 1 diabetes - occurring in about 40% of cases - than it is in cases of type 2 diabetes.6

The condition is also more likely to occur among people who have stopped sensing the early warning signs due to frequently having low blood glucose levels and among those who achieve tight glycemic control. The exact mechanism of hypoglycemia unawareness is not fully understood, however.1,2,5,6

Recent episodes of hypoglycemia lead to a shift in the thresholds for symptoms of hypoglycemia, leading future episodes to occur at progressively lower glucose concentrations. As a result, patients with recurrent hypoglycemia often tolerate abnormally low blood glucose levels without experiencing symptoms.4

If episodes of hypoglycemia are frequently occurring, it is important to consult a doctor. Hypoglycemia may be related to the treatment regime rather than any mistakes over missed meals, excess insulin, alcohol consumption and physical activity

Hyperglycemia

Hyperglycemia is a term referring to high blood glucose levels - the condition that often leads to a diagnosis of diabetes.

High blood glucose levels are the defining feature of diabetes, but once the disease is diagnosed, hyperglycemia is a signal of poor control over the condition.

Hyperglycemia is defined by certain high levels of blood glucose:1

Fasting levels greater than 7.0 mmol/L (126 mg/dL)

Two-hours postprandial (after a meal) levels greater than 11.0 mmol/L (200 mg/dL).

Chronic hyperglycemia usually leads to the development of diabetic complications.2

Symptoms of hyperglycemia

The most common symptoms of diabetes itself are related to hyperglycemia - the classic symptoms of frequent urination and thirst.2,3

Hyperglycemia is defined as having a fasting blood glucose level greater than 126 mg/dL.

Typical signs and symptoms of hyperglycemia that has been confirmed by blood glucose measurement include:1,3,4

Thirst and hunger

Dry mouth

Frequent urination, particularly at night

Tiredness

Recurrent infections, such as thrush

Weight loss

Vision blurring.

Learn more about diabetes symptoms.

Causes of hyperglycemiaHyperglycemia often leads to the diagnosis of diabetes. For people already diagnosed and treated for diabetes, however, poor control over blood sugar levels leads to the condition. Causes of this include:1,3,4

Eating more or exercising less than usual

Insufficient amount of insulin treatment (more commonly in cases of type 1 diabetes)

Insulin resistance in type 2 diabetes

Illness such as the flu

Psychological and emotional stress

The "dawn phenomenon" or "dawn effect" - an early morning hormone surge

Treatment and prevention of hyperglycemiaPrevention of hyperglycemia for people with a diabetes diagnosis is a matter of good self-monitoring and management of blood glucose levels, including adherence to insulin regimes if necessary.4

For someone who has not been diagnosed with diabetes, symptoms of hyperglycemia need to be reported to a doctor so that they can test for diabetes - other conditions can also lead to hyperglycemia.4

Control of high blood sugar is important to prevent complications caused by chronic hyperglycemia. A doctor may need to review the treatment plan for a diabetes patient who becomes hyperglycemic and they may decide to take one of the following actions: 4

Raise the insulin dose (learn more about insulin treatment)

Recommend dietary changes (learn more about diet and diabetes)

Recommend more exercise (learn more about exercise and diabetes)

Recommend closer glucose monitoring (learn more about self-monitoring).

Hyperglycemia can lead to diabetic ketoacidosisIt is important to attend to hyperglycemia since it can lead to a dangerous complication known as ketoacidosis that can result in coma and even death. Ketoacidosis rarely occurs in type 2 diabetes, typically occurring in cases of type 1 diabetes.3

High levels of glucose in the blood mean that insufficient levels of glucose are available to cells for their energy needs. As a result, the body resorts to breaking down fat so that energy is derived from fatty acids. This breakdown produces ketones, leading to higher acidity of the blood.2,3

Diabetic ketoacidosis requires urgent medical attention and, alongside hyperglycemia and its symptoms, is signaled by:2,4

Nausea or vomiting

Abdominal pain

A fruity smell on the breath

Drowsiness or confusion

Hyperventilation

Dehydration

Loss of consciousness.

Hospital treatment of ketoacidosis includes the administering of intravenous fluids and insulin

Taking Insulin

Having insulin-dependent diabetes means a lifelong dependence on daily injections of insulin. In addition to people with type 1 diabetes, those with type 2 diabetes that is unresponsive to oral drugs must also take insulin.1

A typical patient with type 1 diabetes may need more than 60,000 injections across their lifetime, requiring two or more injections every day.2

"Ever since the introduction of insulin for the treatment of diabetes, methods of administering it other than by injection have been investigated." That is a quote from a paper published in The Lancet in 1940, and investigations continue to this day.3

The main obstacle to finding a way of delivering insulin in pill form is the digestive system itself - either the gut breaks the insulin down or the insulin moves through intact because it is unable to pass through the gastrointestinal membrane.2

Different preparations of insulin

In the US, all insulin that is sold has been manufactured in a laboratory. Although animal insulins used to be available, preparations from pigs and cattle have now been withdrawn from the market. Information and warnings about importing these animal preparations from abroad have been published by the US Food and Drug Administration.4-6

Analogs of human insulin are manufactured forms with some structural changes built in, differing in their amino acid sequence to alter their pharmacological characteristics.6

Insulin can be manufactured to produce different actions. The rapid-acting insulins are insulin glulisine, insulin lispro and insulin aspart. Short-acting insulins are insulin regular, while intermediate-acting insulins are neutral protamine Hagedorn (NPH) insulin, also known as isophane insulin. Finally, the long-acting insulins are insulin detemir and insulin glargine.4

Different preparations of insulin provide a range of options in terms of how quickly they take effect, their peak time of action and their overall duration of effect:4,5

Rapid-acting insulin analogs have an onset of action at between 5-15 minutes, a peak action at 30-90 minutes and an overall duration of effect of 3-5 hours

Short-acting, regular insulin has an onset of action at between 30-60 minutes, a peak action at 2-3 hours and an overall duration of effect of 5-8 hours. The optimum time for injecting is 30 minutes before eating

Intermediate-acting insulins have an onset of action at between 2-4 hours, a peak action at 4-12 hours and an overall duration of effect of 10-18 hours

Long-acting insulins have an onset of action at between 2-10 hours, a peak action at 6-16 hours (except insulin glargine, which has no peak) and an overall duration of effect of 16-24 hours. These insulins maintain glucose levels fairly uniformly over a 24-hour period.

Insulins may also be mixed at 30:70, 25:75 and 50:50 combinations to produce two peak times of action.5

Practical advice for injecting insulinWith practice and good technique, injecting insulin can become more comfortable. The needle is very small, and injection is not into a muscle or vein but under the skin. The three areas of skin most commonly used are the stomach, the buttocks and the thighs.7-9

The choice of site depends on a number of factors but can be rotated to help avoid the formation of lumps. Different sites result in different rates of absorption. Insulin is absorbed quickest through the abdomen, followed by the arm, and then the thigh and finally the buttocks.4,9 If physical exertion takes place after injection, this also increases absorption by increasing blood flow. Massage of the injection site also has an effect.8

Injections to the same area should be varied by keeping injections a couple of finger widths apart. Other practical tips include:8

Avoiding the belly button, the inner thigh, the lower buttock, scars and broken blood vessels or varicose veins

If using the thigh, keep injections at least 4 inches below the top of the leg and above the knee

If using the arm, inject into the fatty area at the back, between the shoulder and elbow

If using the buttock, use the hip area.

Insulin side effectsVery rarely, a serious and life-threatening allergic reaction can be experienced after insulin injection. This anaphylaxis is a medical emergency requiring immediate medical care. Serious insulin side effects and anaphylactic reactions are signaled by:1,10

Rash or itching over the whole body

Swelling (edema) of the tongue, throat, arms, hands, feet, ankles or lower legs

Difficulty breathing or shortness of breath

Difficulty swallowing

Wheezing

Dizziness

Blurred vision

Fast heartbeat (tachycardia) or abnormal heartbeat rhythm

Sweating

Weakness

Muscle cramps

Significant weight gain in a short period of time.

Gradually increasing insulin doses under medical supervision is used as a treatment to desensitize an individual with a severe insulin allergy.5,11

Side effects of insulin that are more common include:1,5,7

Hypoglycemia - low blood sugar levels that can result from the timing of the insulin injection. Hypoglycemia might be avoided by shifting a pre-dinner dose of intermediate-acting insulin to bedtime, or reducing a bedtime dose

Weight gain - this may happen initially when insulin therapy is started, due to correction of protein and energy metabolism. Later weight gain may be caused by fluid retention or excessive eating due to hypoglycemia

Lipohypertrophy - raised lumps in the skin caused by repeated injections at the same site; this is can be prevented by the rotation of injection sites

Other local effects - these are less common than lipohypertrophy and include infection, injection site abscess (both of which can be prevented with good injection practices), allergy and lipoatrophy (loss of fat tissue).

Inhaled insulinHuman insulin inhalation powder (Afrezza) became available by prescription in the US in February 2015, the only inhaled insulin available at the time. It is available at around twice the cost of the injected rapid-acting insulins.12

Afrezza is a rapid-acting, dry-powder formulation of recombinant human insulin manufactured by Mannkind and Sanofi and may be used in the treatment of adults with type 1 or type 2 diabetes. In patients with type 1 diabetes, the drug must be used in combination with long-acting insulin.12

A single inhalation of Afrezza is taken at the beginning of meals.12

This is not the first inhaled insulin product to reach the market - a rapid-acting insulin, Exubera, was approved in 2006 but withdrawn just a year later by its manufacturer. That early device was a cumbersome size - about the size of a flashlight.12-14

The Afrezza insulin inhaler device. Image credit: Sanofi/Mannkind.

Afrezza, however, is delivered via a smaller, palm-sized device that can be held comfortably between thumb and finger.

Long-term evidence on the safety of Afrezza is still to be gathered. To date, coughing has been identified as a common side effect, and there has been evidence of throat pain and irritation. As with other insulins, it can also lead to hypoglycemia.12

Patients with chronic lung diseases such as asthma and chronic obstructive pulmonary disease (COPD) are contraindicated from using Afrezza because it increases the risk of bronchospasm. The formulation should also be avoided by patients who smoke or have stopped smoking within the last 6 months.12

Inhaled insulin appears to be similarly effective to injected insulin at controlling blood glucose levels.6,8 One review says Afrezza should be reserved for otherwise healthy adults with diabetes who do not have lung disease and who are unwilling or unable to use injectable insulin

Ever since the discovery of insulin and its use in treating diabetes, medical research has struggled to find a way of delivering it that accurately mimics the normal physiological action of insulin and overcomes the burden of daily injections.

Insulin Pumps

The main development in this area has been the insulin pump. Researchers are also aiming to develop a fully automated artificial pancreas. Other means of delivering insulin have been launched and continue to be investigated.

Insulin pumps for type 1 diabetesInsulin pumps - or continuous subcutaneous insulin infusion pumps - remove the daily need for multiple injections.

Insulin pumps remove the need for multiple daily injections and offer low variability in glucose levels.

Instead, a cannula - a very thin and flexible plastic tube inserted under the skin using a needle - needs to be replaced every two or three days. As well as requiring fewer needles, insulin pumps may be attractive due to offering flexibility in meal timing and low variability in glucose levels.1-3

Insulin pumps also come with disadvantages, although for most users these are outweighed by the advantages.1 Downsides include:1-3

Higher cost, with some but not all insurance carriers covering their expense

The inconvenience of wearing an external device - sores may develop at the needle site

Training is required - frequent and careful self-monitoring of glucose levels is needed for safe and effective use, as is a sound understanding of the pump's function

Mechanical failure could occur, resulting in interruptions to insulin supply.

An insulin pump continuously releases insulin in small doses (the basal insulin) from its reservoir and can deliver an additional dose (a bolus) when needed. As a result, an insulin pump more closely mimics normal insulin physiology and offers greater accuracy than daily injections. Insulin pumps can also provide better glucose control and better HbA1c readings.1-3

In addition to the greater flexibility afforded in meal planning, using an insulin pump cuts out the unpredictable effects of intermediate- or long-acting insulin, as well as allowing for exercise without the need for a high carbohydrate intake.1

However, insulin pumps can also cause weight gain and lead to complications if the catheter comes out, resulting in missed insulin.1

Insulin pumps for type 2 diabetesType 2 diabetes has seen more recent use of external insulin pumps compared with their established use in cases of type 1 diabetes. The use of insulin pumps in cases of type 2 disease is subject to debate and there is less evidence supporting their use.4,5

In a controlled trial of insulin pump versus daily injection, however, researchers publishing in The Lancet in 2014 concluded:5

"In patients with poorly controlled type 2 diabetes despite using multiple daily injections of insulin, pump treatment can be considered as a safe and valuable treatment option."

Future options for delivering insulinResearch into the use of two hormones in pumps, insulin and glucagon - bi-hormonal therapy - is ongoing. The stability of glucagon, however, remains an obstacle to success.6

The aim of such a combination is to counter the excess effects of insulin with glucagon - a role that this hormone fulfills in people without diabetes. The idea has also shown some promise in reducing the risks of hypoglycemia.6

Commercially available glucagon is not stable in aqueous solution for long periods, however, forming potentially cytotoxic fibrils that accumulate quickly and can turn into a gel with the potential to obstruct the pump. Researchers are currently attempting to find a solution to this problem.6

Artificial pancreas

The idea of replacing the role of the pancreas in monitoring and regulating glucose levels has been pursued since the 1960s. Known as the artificial pancreas, the idea is to have a "closed-loop control" of blood glucose in diabetes with a system that combines:7,8

A glucose sensor to measure blood glucose levels

Computer controllers that use a mathematical model of the metabolic system to calculate insulin doses

An insulin infusion device similar to an insulin pump.

A wearable artificial pancreas has become a feasible and safe prospect in recent years, but research continues.8

Oral insulin

Perhaps the best way to deliver insulin would be via the mouth in tablet form, the way most daily medication is taken. Unfortunately, insulin puts up major obstacles to the development of an oral form:9

The gastrointestinal tract's proteolytic enzymes break insulin down

Insulin does not transport readily across the gastrointestinal membrane.

In spite of these obstacles, several research studies have achieved some positive results. Some delivery systems are even in advanced stages of development.9

Once these practical hurdles have been overcome, it remains to be proven whether oral delivery will be safer or more effective than needle delivery. At present, the commercial reality of oral insulin remains elusive.9

Other potential forms of insulin delivery require further research. These include transmucosal delivery - through an intranasal or oral spray, for example - and transdermal delivery using a skin patch.

Diabetes is a lifelong condition that is characterized by a raised blood glucose level. There are two main types of diabetes: type 1 and type 2. Signs of diabetes include an increased sense of thirst, frequent urination, fatigue, weight and muscle loss, cuts or wounds that heal slowly and blurred vision. It is extremely important for diabetes to be diagnosed as early as possible - if left untreated the condition will get progressively worse.

s of 2014, 422 million adults globally had diabetes, nearly four times as many as in

1980, according to findings of the largest ever worldwide study of the condition,

published in The Lancet. Treatment costs now stand at $825 billion a year.

Experts call for interventions to prevent diabetes among high-risk groups.

If the trend continues, over 700 million adults globally will have diabetes by 2025.

Diabetes renders an individual unable to regulate their blood sugar levels, potentially

leading to heart and kidney disease, vision loss and amputations.

Nearly 500 researchers worldwide participated in the study, which was led by a team

from Imperial College London in the UK and involved the Harvard T.H. Chan School

of Public Health in Boston, MA, as well as the World Health Organization (WHO).

It reviewed data for 4.4 million adults, representing most countries in the world.

The study did not differentiate between type 1 and type 2 diabetes, as this

information was largely unavailable from the raw data. Type 2 diabetes accounts for

at least 85-90% of cases.

The teams compared levels of diabetes in adult men and women from 1980-2014.

Diabetes rates double in men

After adjusting figures for age, and taking into account those countries with a larger

aging population, results showed that globally, the rate of diabetes in men more than

doubled, from 4.3% in 1980 to 9% in 2014. Among women, rates rose from 5% in

1980 to 7.9% in 2014.

Fast facts about diabetes

In the US, 21 million people were living with diagnosed diabetes in 2014

Including undiagnosed cases, the Centers for Disease Control and Prevention (CDC) put the total figure at 29.1 million

That is equivalent to 9.3% of the population.

Learn more about diabetes

In the US, the rate of diabetes among men rose from 4.7% in 1980 to 8.2% in 2014. In 1980, 4.3% of American women had diabetes, rising to 6.4% in 2014. The US currently ranks 114th for men and 146th for women in the world.

Countries with the lowest age-adjusted rates of diabetes in 2014 were in

northwestern Europe, specifically in Switzerland, Austria, Denmark, Belgium and the

Netherlands, with a prevalence of around 4% for women and 6% for men.

Polynesia and Micronesia had the highest rates, with more than 1 in 5 adults

affected.

Overall, low- and middle-income countries saw the largest rise.

The financial burden of diabetes, including the cost of treating and managing the

disease and its complications, such as limb amputations, calculated in International

Dollars, stood at $825 billion per year.

The cost of working days lost would increase the sum dramatically, were it included.

Individual countries with the highest costs were China ($170 billion), the US ($105

billion) and India ($73 billion).

Highest levels in Pacific Islands, Middle East and North Africa

Other highlights of the survey show:

The highest increase was in the Pacific Island nations and in the Middle East and North Africa, which now have the highest diabetes levels worldwide

After age-adjustment, 6.6% of men and 4.9% of women in the UK had diabetes in 2014

Around 50% of the 422 million adults with diabetes in 2014 lived in five countries: China, India, US, Brazil and Indonesia.

Senior author Prof. Majid Ezzati, from the School of Public Health at Imperial

College, says:

"This is the first time we have had such a complete global picture about diabetes,

and the data reveals the disease has reached levels that can bankrupt some

countries' health systems. The enormous cost of this disease, to both governments

and individuals, could otherwise go towards life essentials such as food and

education."

Prof. Ezzati believes that the key to tackling the crisis is to focus on helping

individuals who are at risk of developing the condition.

He calls for "financially accessible and effective health systems that can highlight

those at high risk of diabetes or at pre-diabetes stage."

This, he says, will enable health care staff to provide medication and lifestyle advice

that can slow or prevent the development of diabetes. This has already been done in

some European countries.

Prof. Goodarz Danaei, co-lead author of the study from Harvard T.H. Chan School

of Public Health, focuses on the need to control obesity, the most important risk

factor for diabetes.

Prof. Danaei suggests that genetics and environmental factors, fetal and early life

conditions may contribute to the high rates of diabetes in some countries.

An unhealthy lifestyle, he says, can exacerbate the risk of diabetes among people

with certain genotypes, as can inadequate nutrition during pregnancy and in early

life.

Prof. Danaei recommends addressing nutrition throughout the lifespan in order to

prevent diabetes.

Interactive maps and data for individual countries are also available.

Medical News Today reported last week on work by the same team, revealing an

equally dramatic rise in global obesity levels.

Type 1 Diabetes - OverviewType 1 Diabetes is also known commonly as Juvenile Diabetes or insulin dependent

diabetes. This happens to be a chronic disease which leads the pancreas to produce little or

almost no amount of insulin into the bloodstream. Insulin is a hormone which is known to

allow sugar or glucose to enter the cells in order to produce energy for the body. There are

different factors that are known to cause Type 1 Diabetes. Some of these factors may be

genetic in nature or could be present in the environment as per the exposure towards

different viruses.

Though it has been known that the Type 1 diabetes appears typically during the childhood

of a person, it has also been seen in adults. In spite of a great deal of research, no

permanent cure has been found for Type 1 Diabetes. However, with the help of proper

treatment, the disease can be managed and people can live a normal and healthy life.

Signs and Symptoms of Type 1 Diabetes:The symptoms for Type 1 Diabetes can come out quickly once it appears. Some of the

noteworthy symptoms are as follows:

Increase in the thirst and frequent urination

Extreme hunger

A great deal of weight loss

Increased fatigue

Blurring of the vision

In case you are able to see any of these symptoms, it is highly recommended to see a

doctor. The major cause of Type 1 Diabetes is unknown basically. However, it has been

witnessed in most of the cases that the patients suffering from it have a deformed immune

system. The immune system of their body, which is normally meant to fight against virus

and bacteria, goes on to mistakenly destroy their own insulin producing, islet cells which are

present in the pancreas. Genetics too can come out to play a major role in this; however,

the exposure to certain kinds of viruses is known to trigger this disease basically.

The role of insulin is considered to be tremendous for causing Type 1 Diabetes. Once the

islet cells are destroyed in the pancreas there is little or almost no production of insulin by

the body. Insulin is known to be the hormone which is produced by the pancreas and

therefore, enables the body sugar to enter into the cells in order to bring out the normal

functioning of the body. With the lower amount of insulin in the body, the amount of blood

sugar too is lowered. Glucose – which is a form of sugar present in the body is one of the

major sources of energy for the cells which makes up the muscles and other tissues.

Glucose originates from two major sources in the body – the food that we consume and the

liver cells. When sugar is absorbed in the bloodstream, it enters the cells with the help of

the hormone insulin. The liver is the organ responsible for storing the glucose present in the

body in the form of glycogen. When the insulin levels are low in the body, the liver goes out

to convert the glycogen into glucose and thus keeps the glucose level in the body at a

normal range.

In case of Type 1 Diabetes, there is no insulin present to let the glucose to enter the cells.

This goes out to make sure that the sugar builds up in the bloodstream causing life

threatening complications to come.

Risk Factors For Type 1 Diabetes:There are not much known risk factors for Type 1 Diabetes, however some of the major

possibilities are as follows:

Family History / Genetics: If anyone happens to have a parent or sibling suffering from

Type 1 Diabetes, he is at a greater risk of contracting the disease. Also, the researchers

have identified some genes which are responsible for causing Type 1 Diabetes. In some

of the cases, the genetic testing too has been done to determine the risks for causing

Type 1 diabetes.

Geography: If people travel away from the equator, they are at a greater risk of

contracting the disease.

Viral Exposures: It has been found that exposure to the Epstein Barr Virus has been

known to trigger the autoimmune system of the body, leading to the destruction of the

islet cells and infection of the same.

Dietary Factors: Omega 3 Fatty acids are known to offer protection against the disease.

Drinking a large amount of water too has been known to do away with the risk of the

disease. Also, consuming dairy products can increase the risk of infants being infected

with the disease.

Complications from Type 1 Diabetes:Complications tend to develop from Type 1 Diabetes. Some of the complications from the

disease tend to be disabling for the person and may prove to be life threatening in the long

run.

Heart Disease – Diabetes is known to increase the risk of cardiovascular problems in

people. This may include coronary heart disease accompanied by angina, heart attack and

even stroke in some of the severe cases. Narrowing down of the arteries along with high

blood pressure are some of the other complications.

Nerve Damage – Excess sugar in the body can go out to injure the capillaries of the body,

especially of the legs. Not only that, sometimes, the patient may observe tingling sensation

in the body along with the pain towards the tips and the toes. With no controlling of the

blood sugar level, people may also be affected with damage to the nerves and the

gastrointestinal structure.

Kidney Damage – Kidneys contain a large number of blood vessels which are known to

filter the waste from the body. With diabetes, people can cause damage to the filtering

system of the body, which can further lead to the kidney failure, which may require dialysis

and kidney transplant in the later stages.

Eye Damage – diabetes tends to damage the blood vessels of the retina in the eye, which

can further lead to blindness. Not only that, it also increases the risk of contracting cataract

and glaucoma.

Diagnosis Of Type 1 DiabetesThere are many tests in place for the diagnosis of Type 1 Diabetes.

Glycated Haemoglobin Test: This test is used in order to measure the average blood

sugar level of a person for the last two to three months. Not only that, it can measure the

percentage of blood sugar that has been attached with haemoglobin in order to check

whether it is enough. It has been seen that a level of 6.5 and higher indicates that a

person is suffering from diabetes.

Random Blood Sugar Test: In this a random sample of the blood is taken. In case the

sample shows a sugar level of 200 mg/dl and above it, suggests that a person is

suffering from diabetes.

Fasting Blood Sugar Test: In this a sample of the blood is taken after an overnight fast.

In this, if the fasting blood sugar level is less than 100, then it is normal. Otherwise, it is

found that the person is suffering from diabetes.

Treatment and Drugs for Diabetes:For a person suffering from Type 1 Diabetes, the treatment is going to need a lifetime of

commitment. Some of the daily routine that needs to be followed is as followed:

Taking insulin

Exercising regularly and making sure to maintain a healthy weight

Eating healthy foods

Monitoring the blood sugar level

 The goal of the treatment is to make sure that the blood sugar level is kept at bay. Insulin

level has to be maintained in the bloodstream and there are two different ways of injecting

insulin into the body.

With a fine needle and a syringe

An insulin pen, with cartridge filled with insulin

An insulin pump

 Healthy need of food as well as physical activity is required in order to maintain a healthy

lifestyle for people who are suffering from Diabetes Type 1.

Diabetes mellitus (or diabetes) is a chronic, lifelong condition that affects your body's ability to use the energy found in food. There are three major types of diabetes: type 1 diabetes, type 2 diabetes, and gestational diabetes.

All types of diabetes mellitus have something in common. Normally, your body breaks down the sugars and carbohydrates you eat into a special sugar called glucose. Glucose fuels the cells in your body. But the cells need insulin, a hormone, in your bloodstream in order to take in the glucose and use it for energy. With diabetes mellitus, either your body doesn't make enough insulin, it can't use the insulin it does produce, or a combination of both.

Since the cells can't take in the glucose, it builds up in your blood. High levels of blood glucose can damage the tiny blood vessels in your kidneys, heart, eyes, or nervous system. That's why diabetes -- especially if left untreated -- can eventually cause heart disease, stroke, kidney disease, blindness, and nerve damage to nerves in the feet.

slideshow

A Visual Guide to Type 2 Diabetesstart

Type 1 Diabetes

Type 1 diabetes is also called insulin-dependent diabetes. It used to be called juvenile-onset diabetes, because it often begins in childhood.

Type 1 diabetes is an autoimmune condition. It's caused by the body attacking its own pancreas with antibodies. In people with type 1 diabetes, the damaged pancreas doesn't make insulin.

This type of diabetes may be caused by a genetic predisposition. It could also be the result of faulty beta cells in the pancreas that normally produce insulin.

A number of medical risks are associated with type 1 diabetes. Many of them stem from damage to the tiny blood vessels in your eyes (called diabetic retinopathy), nerves (diabetic neuropathy), and kidneys (diabetic nephropathy). Even more serious is the increased risk of heart disease and stroke.

Treatment for type 1 diabetes involves taking insulin, which needs to be injected through the skin into the fatty tissue below. The methods of injecting insulin include:

Syringes Insulin pens that use pre-filled cartridges and a fine needle Jet injectors that use high pressure air to send a spray of insulin through the skin

Insulin pumps that dispense insulin through flexible tubing to a catheter under the skin of the abdomen

Type 1 Diabetes continued...

A periodic test called the A1C blood test estimates glucose levels in your blood over the previous three months. It's used to help identify overall glucose level control and the risk of complications from diabetes, including organ damage.

Having type 1 diabetes does require significant lifestyle changes that include:

Frequent testing of your blood sugar levels Careful meal planning Daily exercise Taking insulin and other medications as needed

People with type 1 diabetes can lead long, active lives if they carefully monitor their glucose, make the needed lifestyle changes, and adhere to the treatment plan.

slideshow

A Visual Guide to Type 2 Diabetesstart

Type 2 Diabetes

By far, the most common form of diabetes is type 2 diabetes, accounting for 95% of diabetes cases in adults. Some 26 million American adults have been diagnosed with the disease.

Type 2 diabetes used to be called adult-onset diabetes, but with the epidemic of obese and overweight kids, more teenagers are now developing type 2 diabetes. Type 2 diabetes was also called non-insulin-dependent diabetes.

Type 2 diabetes is often a milder form of diabetes than type 1. Nevertheless, type 2 diabetes can still cause major health complications, particularly in the smallest blood vessels in the body that nourish the kidneys, nerves, and eyes. Type 2 diabetes also increases your risk of heart disease and stroke.

With Type 2 diabetes, the pancreas usually produces some insulin. But either the amount produced is not enough for the body's needs, or the body's cells are resistant to it. Insulin resistance, or lack of sensitivity to insulin, happens primarily in fat, liver, and muscle cells.

People who are obese -- more than 20% over their ideal body weight for their height -- are at particularly high risk of developing type 2 diabetes and its related medical problems. Obese people have insulin resistance. With insulin resistance, the pancreas has to work overly hard to produce more insulin. But even then, there is not enough insulin to keep sugars normal.

There is no cure for diabetes. Type 2 diabetes can, however, be controlled with weight management, nutrition, and exercise. Unfortunately, type 2 diabetes tends to progress, and diabetes medications are often needed.

An A1C test is a blood test that estimates average glucose levels in your blood over the previous three months. Periodic A1C testing may be advised to see how well diet, exercise, and medications are working to control blood sugar and prevent organ damage. The A1C test is typically done a few times a year.

Types of Diabetes Mellitus(continued)

Gestational Diabetes

Diabetes that's triggered by pregnancy is called gestational diabetes (pregnancy, to some degree, leads to insulin resistance). It is often diagnosed in middle or late pregnancy. Because high blood sugar levels in a mother are circulated through the placenta to the baby, gestational diabetes must be controlled to protect the baby's growth and development.

According to the National Institutes of Health, the reported rate of gestational diabetes is between 2% to 10% of pregnancies. Gestational diabetes usually resolves itself after pregnancy. Having gestational diabetes does, however, put mothers at risk for developing type 2 diabetes later in life. Up to 10% of women with gestational diabetes develop type 2 diabetes. It can occur anywhere from a few weeks after delivery to months or years later.

With gestational diabetes, risks to the unborn baby are even greater than risks to the mother. Risks to the baby include abnormal weight gain before birth, breathing problems at birth, and higher obesity and

diabetes risk later in life. Risks to the mother include needing a cesarean section due to an overly large baby, as well as damage to heart, kidney, nerves, and eye.

Treatment during pregnancy includes working closely with your health care team and:

slideshow

A Visual Guide to Type 2 Diabetesstart

Careful meal planning to ensure adequate pregnancy nutrients without excess fat and calories Daily exercise Controlling pregnancy weight gain Taking diabetes insulin to control blood sugar levels if needed

Other Forms of Diabetes

A few rare kinds of diabetes can result from specific conditions. For example, diseases of the pancreas, certain surgeries and medications, or infections can cause diabetes. These types of diabetes account for only 1% to 5% of all cases of diabetes.

Diabetes facts

Diabetes is a chronic condition associated with abnormally high levels of sugar (glucose) in the blood. Insulin produced by the pancreas lowers blood

glucose. Absence or insufficient production of insulin, or an inability of the body to properly use insulin causes diabetes.

The two types of diabetes are referred to as type 1 and type 2. Former names for these conditions were insulin-dependent and non-insulin-dependent diabetes, or juvenile onset and adult onset diabetes.

Symptoms of diabetes includeo increased urine output,o excessive thirst,o weight loss ,o hunger,o fatigue ,o skin problemso slow healing wounds,o yeast infections,o blurred vision , ando tingling or numbness in the feet or toes.

If you think you have diabetes contact a health-care professional. Diabetes is diagnosed by blood sugar (glucose) testing. The major complications of diabetes are both acute and chronic.

o Acute complications: dangerously elevated blood sugar (hyperglycemia) or abnormally low blood sugar (hypoglycemia) due to diabetes medications

o Chronic complications: disease of the blood vessels (both small and large) that can damage the feet, eyes, kidneys, nerves, and heart

Diabetes treatment depends on the type and severity of the diabetes. Type 1 diabetes is treated with insulin, exercise, and a diabetic diet. Type 2 diabetes is first treated with weight reduction, a type 2 diabetic diet, and exercise. When these measures fail to control the elevated blood sugars, oral medications are used. If oral medications are still insufficient, insulin and other injectable medications are considered.

Type 1 diabetes cannot be prevented; however, type 2 diabetes may be prevented in some cases by maintaining a healthy weight and getting regular exercise. 

lasts a lifetime.

How many people in the US have diabetes?

Diabetes affects approximately 29 million people in the United States, while another 86 million have prediabetes. An estimated 8 million people in the United States have diabetes and don't even know it. Over time, diabetes can lead to blindness, kidney failure, and nerve damage. These types of damage are the result of damage to small vessels, referred to as microvascular disease. Diabetes is also an important factor in accelerating the hardening and narrowing of the arteries (atherosclerosis), leading to strokes, coronary heart disease, and other large blood vessel diseases. This is referred to as macrovascular disease.

From an economic perspective, the total annual cost of diabetes in 2012 was estimated to be 245 billion dollars in the United States. This included 116 billion in direct medical costs (healthcare costs) for people with diabetes and another 69 billion in other costs due to disability, premature death, or work loss. Medical expenses for people with diabetes are over two times higher than those for people who do not have diabetes. Remember, these numbers reflect only the population in the United States. Globally, the statistics are staggering.

Diabetes is the 7th leading cause of death in the United States listed on death certificates in recent years. Continue Reading

1. The early symptoms of untreated diabetes are related to elevated blood sugar levels, and loss of glucose in the urine. High amounts of glucose in the urine can cause increased urine output and lead to dehydration. Dehydration causes increased thirst and water consumption.

2. The inability of insulin to perform normally has effects on protein, fat and carbohydrate metabolism. Insulin is an anabolic hormone, that is, one that encourages storage of fat and protein.

3. A relative or absolute insulin deficiency eventually leads to weight loss despite an increase in appetite.

4. Some untreated diabetes patients also complain of fatigue, nausea and vomiting.

5. Patients with diabetes are prone to developing infections of the bladder, skin, and vaginal areas.

6. Fluctuations in blood glucose levels can lead to blurred vision. Extremely elevated glucose levels can lead to lethargy and coma.

How do I know if I have diabetes?

Many people are unaware that they have diabetes, especially in its early stages when symptoms may not be present. There is no definite way to know if you have diabetes without undergoing blood tests to determine your blood glucose levels (see section on Diagnosis of diabetes). See your doctor if you have symptoms of diabetes or if you are concerned about your diabetes risk. Continue Reading

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What causes diabetes?

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Insufficient production of insulin (either absolutely or relative to the body's needs), production of defective insulin (which is uncommon), or the inability of cells to use insulin properly and efficiently leads to hyperglycemia and diabetes. This latter

condition affects mostly the cells of muscle and fat tissues, and results in a condition known as insulin resistance. This is the primary problem in type 2 diabetes. The absolute lack of insulin, usually secondary to a destructive process affecting the insulin-producing beta cells in the pancreas, is the main disorder in type 1 diabetes. In type 2 diabetes, there also is a steady decline of beta cells that adds to the process of elevated blood sugars. Essentially, if someone is resistant to insulin, the body can, to some degree, increase production of insulin and overcome the level of resistance. After time, if production decreases and insulin cannot be released as vigorously, hyperglycemia develops.

Glucose is a simple sugar found in food. Glucose is an essential nutrient that provides energy for the proper functioning of the body cells. Carbohydrates are broken down in the small intestine and the glucose in digested food is then absorbed by the intestinal cells into the bloodstream, and is carried by the bloodstream to all the cells in the body where it is utilized. However, glucose cannot enter the cells alone and needs insulin to aid in its transport into the cells. Without insulin, the cells become starved of glucose energy despite the presence of abundant glucose in the bloodstream. In certain types of diabetes, the cells' inability to utilize glucose gives rise to the ironic situation of "starvation in the midst of plenty". The abundant, unutilized glucose is wastefully excreted in the urine.

Insulin is a hormone that is produced by specialized cells (beta cells) of the pancreas. (The pancreas is a deep-seated organ in the abdomen located behind the stomach.) In addition to helping glucose enter the cells, insulin is also important in tightly regulating the level of glucose in the blood. After a meal, the blood glucose level rises. In response to the increased glucose level, the pancreas normally releases more insulin into the bloodstream to help glucose enter the cells and lower blood glucose levels after a meal. When the blood glucose levels are lowered, the insulin release from the pancreas is turned down. It is important to note that even in the fasting state there is a low steady release of insulin than fluctuates a bit and helps to maintain a steady blood sugar level during fasting. In normal individuals,

such a regulatory system helps to keep blood glucose levels in a tightly controlled range. As outlined above, in patients with diabetes, the insulin is either absent, relatively insufficient for the body's needs, or not used properly by the body. All of these factors cause elevated levels of blood glucose (hyperglycemia).  Continue Reading

What are the risk factors for diabetes?

Risk factors for type 1 diabetes are not as well understood as those for type 2 diabetes. Family history is a known risk factor for type 1 diabetes. Other risk factors can include having certain infections or diseases of the pancreas.

Risk factors for type 2 diabetes and prediabetes are many. The following can raise your risk of developing type 2 diabetes:

Being obese or overweight High blood pressure Elevated levels of triglycerides and low levels of "good" cholesterol (HDL) Sedentary lifestyle Family history Increasing age Polycystic ovary syndrome Impaired glucose tolerance Insulin resistance Gestational diabetes during a pregnancy Ethnic background: Hispanic/Latino Americans, African-Americans, Native

Americans, Asian-Americans, Pacific Islanders, and Alaska natives are at greater risk.

home / diabetes center / diabetes a-z list / diabetes mellitus index / diabetes mellitus article

Diabetes (Type 1 and Type 2)

Medical Author: Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

Medical Editor: William C. Shiel Jr., MD, FACP, FACR

William C. Shiel Jr., MD, FACP, FACR

Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

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Quick GuideType 2 Diabetes Pictures Slideshow: Learn the Warning Signs

What are the different types of diabetes?

There are two major types of diabetes, called type 1 and type 2. Type 1 diabetes was also formerly called insulin dependent diabetes mellitus (IDDM), or juvenile-onset diabetes mellitus. In type 1 diabetes, the pancreas undergoes an autoimmune attack by the body itself, and is rendered incapable of making insulin. Abnormal antibodies have been found in the majority of patients with type 1 diabetes. Antibodies are proteins in the blood that are part of the body's immune system. The patient with type 1 diabetes must rely on insulin medication for survival.

Type 1 diabetes

In autoimmune diseases, such as type 1 diabetes, the immune system mistakenly manufactures antibodies and inflammatory cells that are directed against and cause damage to patients' own body tissues. In persons with type 1 diabetes, the beta cells of the pancreas, which are responsible for insulin production, are attacked by the misdirected immune system. It is believed that the tendency to develop abnormal antibodies in type 1 diabetes is, in part, genetically inherited, though the details are not fully understood.

Exposure to certain viral infections (mumps and Coxsackie viruses) or other environmental toxins may serve to trigger abnormal antibody responses that cause damage to the pancreas cells where insulin is made. Some of the antibodies seen in type 1 diabetes include anti-islet cell antibodies, anti-insulin antibodies and anti-glutamic decarboxylase antibodies. These antibodies can be detected in the majority of patients, and may help determine which individuals are at risk for developing type 1 diabetes.

At present, the American Diabetes Association does not recommend general screening of the population for type 1 diabetes, though screening of high risk individuals, such as those with a first degree relative (sibling or parent) with type 1 diabetes should be encouraged. Type 1 diabetes tends to occur in young, lean individuals, usually before 30 years of age; however, older patients do present with this form of diabetes on occasion. This subgroup is referred to as latent autoimmune diabetes in adults (LADA). LADA is a slow, progressive form of type 1 diabetes. Of all the people with diabetes, only approximately 10% have type 1 diabetes and the remaining 90% have type 2 diabetes.

Type 2 diabetes was also previously referred to as non-insulin dependent diabetes mellitus (NIDDM), or adult-onset diabetes mellitus (AODM). In type 2 diabetes, patients can still produce insulin, but do so relatively inadequately for their body's needs, particularly in the face of insulin resistance as discussed above. In many

cases this actually means the pancreas produces larger than normal quantities of insulin. A major feature of type 2 diabetes is a lack of sensitivity to insulin by the cells of the body (particularly fat and muscle cells).

In addition to the problems with an increase in insulin resistance, the release of insulin by the pancreas may also be defective and suboptimal. In fact, there is a known steady decline in beta cell production of insulin in type 2 diabetes that contributes to worsening glucose control. (This is a major factor for many patients with type 2 diabetes who ultimately require insulin therapy.) Finally, the liver in these patients continues to produce glucose through a process called gluconeogenesis despite elevated glucose levels. The control of gluconeogenesis becomes compromised.

While it is said that type 2 diabetes occurs mostly in individuals over 30 years old and the incidence increases with age, an alarming number of patients with type 2 diabetes are barely in their teen years. Most of these cases are a direct result of poor eating habits, higher body weight, and lack of exercise.

While there is a strong genetic component to developing this form of diabetes, there are other risk factors - the most significant of which is obesity. There is a direct relationship between the degree of obesity and the risk of developing type 2 diabetes, and this holds true in children as well as adults. It is estimated that the chance to develop diabetes doubles for every 20% increase over desirable body weight.

Regarding age, data shows that for each decade after 40 years of age regardless of weight there is an increase in incidence of diabetes. The prevalence of diabetes in persons 65 years of age and older is around 26%. Type 2 diabetes is also more common in certain ethnic groups. Compared with a 7% prevalence in non-Hispanic Caucasians, the prevalence in Asian Americans is estimated to be 9%, in Hispanics 13%, in blacks around 13%, and in certain Native American communities 20% to

50%. Finally, diabetes occurs much more frequently in women with a prior history of diabetes that develops during pregnancy (gestational diabetes

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Diabetes (Type 1 and Type 2)

Medical Author: Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

Medical Editor: William C. Shiel Jr., MD, FACP, FACR

William C. Shiel Jr., MD, FACP, FACR

Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

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What are the other types of diabetes?

Gestational diabetes

Diabetes can occur temporarily during pregnancy, and reports suggest that it occurs in 2% to 10% of all pregnancies. Significant hormonal changes during pregnancy can lead to blood sugar elevation in genetically predisposed individuals. Blood sugar elevation during pregnancy is called gestational diabetes. Gestational diabetes usually resolves once the baby is born. However, 35% to 60% of women with gestational diabetes will eventually develop type 2 diabetes over the next 10 to 20 years, especially in those who require insulin during pregnancy and those who remain overweight after their delivery. Women with gestational diabetes are usually asked to undergo an oral glucose tolerance test about six weeks after giving birth to determine if their diabetes has persisted beyond the pregnancy, or if any evidence (such as impaired glucose tolerance) is present that may be a clue to a risk for developing diabetes.

Secondary diabetes

"Secondary" diabetes refers to elevated blood sugar levels from another medical condition. Secondary diabetes may develop when the pancreatic tissue responsible for the production of insulin is destroyed by disease, such as chronic pancreatitis (inflammation of the pancreas by toxins like excessive alcohol), trauma, or surgical removal of the pancreas.

Hormonal disturbances

Diabetes can also result from other hormonal disturbances, such as excessive growth hormone production (acromegaly) and Cushing's syndrome. In acromegaly, a pituitary gland tumor at the base of the brain causes excessive production of growth hormone, leading to hyperglycemia. In Cushing's syndrome, the adrenal glands produce an excess of cortisol, which promotes blood sugar elevation.

Medications

Certain medications may worsen diabetes control, or "unmask" latent diabetes. This is seen most commonly when steroid medications (such as prednisone) are taken and also with medications used in the treatment of HIV infection (AIDS).  Continue Reading

What kind of doctor treats diabetes?

Endocrinology is the specialty of medicine that deals with hormone disturbances, and both endocrinologists and pediatric endocrinologists manage patients with diabetes. People with diabetes may also be treated by family medicine or internal medicine specialists. When complications arise, people with diabetes may be treated by other specialists, including neurologists, gastroenterologists, ophthalmologists, surgeons, cardiologists, or others.

How is diabetes diagnosed?

The fasting blood glucose (sugar) test is the preferred way to diagnose diabetes. It is easy to perform and convenient. After the person has fasted overnight (at least 8 hours), a single sample of blood is drawn and sent to the laboratory for analysis. This can also be done accurately in a doctor's office using a glucose meter.

Normal fasting plasma glucose levels are less than 100 milligrams per deciliter (mg/dl).

Fasting plasma glucose levels of more than 126 mg/dl on two or more tests on different days indicate diabetes.

A random blood glucose test can also be used to diagnose diabetes. A blood glucose level of 200 mg/dl or higher indicates diabetes.

When fasting blood glucose stays above 100mg/dl, but in the range of 100-126mg/dl, this is known as impaired fasting glucose (IFG). While patients with IFG or prediabetes do not have the diagnosis of diabetes, this condition carries with it its own risks and concerns, and is addressed elsewhere.

The oral glucose tolerance test

Though not routinely used any longer, the oral glucose tolerance test (OGTT) is a gold standard for making the diagnosis of type 2 diabetes. It is still commonly used for diagnosing gestational diabetes and in conditions of pre-diabetes, such as polycystic ovary syndrome. With an oral glucose tolerance test, the person fasts overnight (at least eight but not more than 16 hours). Then first, the fasting plasma glucose is tested. After this test, the person receives an oral dose (75 grams) of glucose. There are several methods employed by obstetricians to do this test, but the one described here is standard. Usually, the glucose is in a sweet-tasting liquid that the person drinks. Blood samples are taken at specific intervals to measure the blood glucose.

For the test to give reliable results:

The person must be in good health (not have any other illnesses, not even a cold).

The person should be normally active (not lying down, for example, as an inpatient in a hospital), and

The person should not be taking medicines that could affect the blood glucose.

The morning of the test, the person should not smoke or drink coffee.

The classic oral glucose tolerance test measures blood glucose levels five times over a period of three hours. Some physicians simply get a baseline blood sample followed by a sample two hours after drinking the glucose solution. In a person without diabetes, the glucose levels rise and then fall quickly. In someone with diabetes, glucose levels rise higher than normal and fail to come back down as fast.

People with glucose levels between normal and diabetic have impaired glucose tolerance (IGT) or insulin resistance. People with impaired glucose tolerance do not have diabetes, but are at high risk for progressing to diabetes. Each year, 1% to 5% of people whose test results show impaired glucose tolerance actually eventually develop diabetes. Weight loss and exercise may help people with impaired glucose tolerance return their glucose levels to normal. In addition, some physicians advocate the use of medications, such as metformin (Glucophage), to help prevent/delay the onset of overt diabetes.

Research has shown that impaired glucose tolerance itself may be a risk factor for the development of heart disease. In the medical community, most physicians now understand that impaired glucose tolerance is not simply a precursor of diabetes, but is its own clinical disease entity that requires treatment and monitoring.

Evaluating the results of the oral glucose tolerance test

Glucose tolerance tests may lead to one of the following diagnoses:

Normal response: A person is said to have a normal response when the 2-hour glucose level is less than 140 mg/dl, and all values between 0 and 2 hours are less than 200 mg/dl.

Impaired glucose tolerance (prediabetes): A person is said to have impaired glucose tolerance when the fasting plasma glucose is less than 126 mg/dl and the 2-hour glucose level is between 140 and 199 mg/dl.

Diabetes: A person has diabetes when two diagnostic tests done on different days show that the blood glucose level is high.

Gestational diabetes: A pregnant woman has gestational diabetes when she has any two of the following:, a fasting plasma glucose of 92 mg/dl or more, a 1-hour glucose level of 180 mg/dl or more, or a 2-hour glucose level of 153 mg/dl, or more

Why is blood sugar checked at home?

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Home blood sugar (glucose) testing is an important part of controlling blood sugar. One important goal of diabetes treatment is to keep the blood glucose levels near the normal range of 70 to 120 mg/dl before meals and under 140 mg/dl at two hours after eating. Blood glucose levels are usually tested before and after meals, and at bedtime. The blood sugar level is typically determined by pricking a fingertip with a lancing device and applying the blood to a glucose meter, which reads the value. There are many meters on the market, for example, Accu-Check Advantage, One Touch Ultra, Sure Step and Freestyle. Each meter has its own advantages and disadvantages (some use less blood, some have a larger digital readout, some take a shorter time to give you results, etc). The test results are then used to help patients make adjustments in medications, diets, and physical activities.

There are some interesting developments in blood glucose monitoring including continuous glucose sensors. The new continuous glucose sensor systems involve an implantable cannula placed just under the skin in the abdomen or in the arm. This

cannula allows for frequent sampling of blood glucose levels. Attached to this is a transmitter that sends the data to a pager-like device. This device has a visual screen that allows the wearer to see, not only the current glucose reading, but also the graphic trends. In some devices, the rate of change of blood sugar is also shown. There are alarms for low and high sugar levels. Certain models will alarm if the rate of change indicates the wearer is at risk for dropping or rising blood glucose too rapidly. One version is specifically designed to interface with their insulin pumps. In most cases the patient still must manually approve any insulin dose (the pump cannot blindly respond to the glucose information it receives, it can only give a calculated suggestion as to whether the wearer should give insulin, and if so, how much). However, in 2013 the US FDA approved the first artificial pancreas type device, meaning an implanted sensor and pump combination that stops insulin delivery when glucose levels reach a certain low point. All of these devices need to be correlated to fingersticks measurements for a few hours before they can function independently. The devices can then provide readings for 3 to 5 days.

Diabetes experts feel that these blood glucose monitoring devices give patients a significant amount of independence to manage their disease process; and they are a great tool for education as well. It is also important to remember that these devices can be used intermittently with fingerstick measurements. For example, a well-controlled patient with diabetes can rely on fingerstick glucose checks a few times a day and do well. If they become ill, if they decide to embark on a new exercise regimen, if they change their diet and so on, they can use the sensor to supplement their fingerstick regimen, providing more information on how they are responding to new lifestyle changes or stressors. This kind of system takes us one step closer to closing the loop, and to the development of an artificial pancreas that senses insulin requirements based on glucose levels and the body's needs and releases insulin accordingly - the ultimate goal.

Hemoglobin A1c (HBA1c)

To explain what hemoglobin A1c is, think in simple terms. Sugar sticks, and when it's around for a long time, it's harder to get it off. In the body, sugar sticks too, particularly to proteins. The red blood cells that circulate in the body live for about three months before they die off. When sugar sticks to these hemoglobin proteins in these cells, it is known as glycosylated hemoglobin or hemoglobin A1c (HBA1c). Measurement of HBA1c gives us an idea of how much sugar is present in the bloodstream for the preceding three months. In most labs, the normal range is 4%-5.9 %. In poorly controlled diabetes, its 8.0% or above, and in well controlled patients it's less than 7.0% (optimal is < 6.5%). The benefits of measuring A1c is that is gives a more reasonable and stable view of what's happening over the course of time (three months), and the value does not vary as much as finger stick blood sugar measurements. There is a direct correlation between A1c levels and average blood sugar levels as follows.

While there are no guidelines to use A1c as a screening tool, it gives a physician a good idea that someone is diabetic if the value is elevated. Right now, it is used as a standard tool to determine blood sugar control in patients known to have diabetes.

HBA1c(%) Mean blood sugar (mg/dl)

6 135

7 170

8 205

9 240

HBA1c(%) Mean blood sugar (mg/dl)

10 275

11 310

12 345

The American Diabetes Association currently recommends an A1c goal of less than 7.0% with A1C goal for selected individuals of as close to normal as possible (<6%) without significant hypoglycemia. Other Groups such as the American Association of Clinical Endocrinologists feel that an A1c of <6.5% should be the goal.

Of interest, studies have shown that there is about a 35% decrease in relative risk for microvascular disease for every 1% reduction in A1c. The closer to normal the A1c, the lower the absolute risk for microvascular complications.

It should be mentioned here that there are a number of conditions in which an A1c value may not be accurate. For example, with significant anemia, the red blood cell count is low, and thus the A1c is altered. This may also be the case in sickle cell disease and other hemoglobinopathies

What are the acute complications of diabetes?

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1. Severely elevated blood sugar levels due to an actual lack of insulin or a relative deficiency of insulin.

2. Abnormally low blood sugar levels due to too much insulin or other glucose-lowering medications.

Acute complications of type 2 diabetes

In patients with type 2 diabetes, stress, infection, and medications (such as corticosteroids) can also lead to severely elevated blood sugar levels. Accompanied by dehydration, severe blood sugar elevation in patients with type 2 diabetes can lead to an increase in blood osmolality (hyperosmolar state). This condition can worsen and lead to coma (hyperosmolar coma). A hyperosmolar coma usually occurs in elderly patients with type 2 diabetes. Like diabetic ketoacidosis, a hyperosmolar coma is a medical emergency. Immediate treatment with intravenous fluid and insulin is important in reversing the hyperosmolar state. Unlike patients with type 1 diabetes, patients with type 2 diabetes do not generally develop ketoacidosis solely on the basis of their diabetes. Since in general, type 2 diabetes occurs in an older population, concomitant medical conditions are more likely to be present, and these patients may actually be sicker overall. The complication and death rates from hyperosmolar coma is thus higher than in diabetic ketoacidosis.

Hypoglycemia means abnormally low blood sugar (glucose). In patients with diabetes, the most common cause of low blood sugar is excessive use of insulin or other glucose-lowering medications, to lower the blood sugar level in diabetic patients in the presence of a delayed or absent meal. When low blood sugar levels occur because of too much insulin, it is called an insulin reaction. Sometimes, low blood sugar can be the result of an insufficient caloric intake or sudden excessive physical exertion.

Blood glucose is essential for the proper functioning of brain cells. Therefore, low blood sugar can lead to central nervous system symptoms such as:

dizziness , confusion , weakness , and tremors .

The actual level of blood sugar at which these symptoms occur varies with each person, but usually it occurs when blood sugars are less than 50 mg/dl. Untreated, severely low blood sugar levels can lead to coma, seizures, and, in the worst case scenario, irreversible brain death. 

The treatment of low blood sugar consists of administering a quickly absorbed glucose source. These include glucose containing drinks, such as orange juice, soft drinks (not sugar-free), or glucose tablets in doses of 15-20 grams at a time (for example, the equivalent of half a glass of juice). Even cake frosting applied inside the cheeks can work in a pinch if patient cooperation is difficult. If the individual becomes unconscious, glucagon can be given by intramuscular injection.

Glucagon is a hormone that causes the release of glucose from the liver (for example, it promotes gluconeogenesis). Glucagon can be lifesaving and every patient with diabetes who has a history of hypoglycemia (particularly those on insulin) should have a glucagon kit. Families and friends of those with diabetes need to be taught how to administer glucagon, since obviously the patients will not be able to do it themselves in an emergency situation. Another lifesaving device that should be mentioned is very simple; a medic-alert bracelet should be worn by all patients with diabetes.

Acute complications of type 1 diabetes

Insulin is vital to patients with type 1 diabetes - they cannot live without a source of exogenous insulin. Without insulin, patients with type 1 diabetes develop severely elevated blood sugar levels. This leads to increased urine glucose, which in turn leads to excessive loss of fluid and electrolytes in the urine. Lack of insulin also causes the inability to store fat and protein along with breakdown of existing fat and protein stores. This dysregulation, results in the process of ketosis and the release of ketones into the blood. Ketones turn the blood acidic, a condition called diabetic ketoacidosis (DKA). Symptoms of diabetic ketoacidosis include nausea, vomiting,

and abdominal pain. Without prompt medical treatment, patients with diabetic ketoacidosis can rapidly go into shock, coma, and even death may result.

Diabetic ketoacidosis can be caused by infections, stress, or trauma, all of which may increase insulin requirements. In addition, missing doses of insulin is also an obvious risk factor for developing diabetic ketoacidosis. Urgent treatment of diabetic ketoacidosis involves the intravenous administration of fluid, electrolytes, and insulin, usually in a hospital intensive care unit. Dehydration can be very severe, and it is not unusual to need to replace 6-7 liters of fluid when a person presents in diabetic ketoacidosis. Antibiotics are given for infections. With treatment, abnormal blood sugar levels, ketone production, acidosis, and dehydration can be reversed rapidly, and patients can recover remarkably well

What are the chronic complications of diabetes?

These diabetes complications are related to blood vessel diseases and are generally classified into small vessel disease, such as those involving the eyes, kidneys and nerves (microvascular disease), and large vessel disease involving the heart and blood vessels (macrovascular disease). Diabetes accelerates hardening of the arteries (atherosclerosis) of the larger blood vessels, leading to coronary heart disease (angina or heart attack), strokes, and pain in the lower extremities because of lack of blood supply (claudication).

Eye Complications

The major eye complication of diabetes is called diabetic retinopathy. Diabetic retinopathy occurs in patients who have had diabetes for at least five years. Diseased small blood vessels in the back of the eye cause the leakage of protein and blood in the retina. Disease in these blood vessels also causes the formation of small aneurysms (microaneurysms), and new but brittle blood vessels (neovascularization). Spontaneous bleeding from the new and brittle blood vessels can lead to retinal scarring and retinal detachment, thus impairing vision.

To treat diabetic retinopathy, a laser is used to destroy and prevent the recurrence of the development of these small aneurysms and brittle blood vessels. Approximately 50% of patients with diabetes will develop some degree of diabetic retinopathy after 10 years of diabetes, and 80% of diabetics have retinopathy after 15 years of the disease. Poor control of blood sugar and blood pressure further aggravates eye disease in diabetes.

Cataracts and glaucoma are also more common among diabetics. It is also important to note that since the lens of the eye lets water through, if blood sugar concentrations vary a lot, the lens of the eye will shrink and swell with fluid accordingly. As a result, blurry vision is very common in poorly controlled diabetes. Patients are usually discouraged from getting a new eyeglass prescription until their blood sugar is controlled. This allows for a more accurate assessment of what kind of glasses prescription is required.

Kidney damage

Kidney damage from diabetes is called diabetic nephropathy. The onset of kidney disease and its progression is extremely variable. Initially, diseased small blood vessels in the kidneys cause the leakage of protein in the urine. Later on, the kidneys lose their ability to cleanse and filter blood. The accumulation of toxic waste products in the blood leads to the need for dialysis. Dialysis involves using a machine that serves the function of the kidney by filtering and cleaning the blood. In patients who do not want to undergo chronic dialysis, kidney transplantation can be considered.

The progression of nephropathy in patients can be significantly slowed by controlling high blood pressure, and by aggressively treating high blood sugar levels. Angiotensin converting enzyme inhibitors (ACE inhibitors) or angiotensin receptor blockers (ARBs) used in treating high blood pressure may also benefit kidney disease in patients with diabetes.

Nerve damage

Nerve damage from diabetes is called diabetic neuropathy and is also caused by disease of small blood vessels. In essence, the blood flow to the nerves is limited, leaving the nerves without blood flow, and they get damaged or die as a result (a term known as ischemia). Symptoms of diabetic nerve damage include numbness, burning, and aching of the feet and lower extremities. When the nerve disease causes a complete loss of sensation in the feet, patients may not be aware of injuries to the feet, and fail to properly protect them. Shoes or other protection should be worn as much as possible. Seemingly minor skin injuries should be attended to promptly to avoid serious infections. Because of poor blood circulation, diabetic foot injuries may not heal. Sometimes, minor foot injuries can lead to serious infection, ulcers, and even gangrene, necessitating surgical amputation of toes, feet, and other infected parts.

Diabetic nerve damage can affect the nerves that are important for penile erection, causing erectile dysfunction (ED, impotence). Erectile dysfunction can also be caused by poor blood flow to the penis from diabetic blood vessel disease.

Diabetic neuropathy can also affect nerves to the stomach and intestines, causing nausea, weight loss, diarrhea, and other symptoms of gastroparesis (delayed emptying of food contents from the stomach into the intestines, due to ineffective contraction of the stomach muscles).

The pain of diabetic nerve damage may respond to traditional treatments with certain medications such as gabapentin (Neurontin), phenytoin (Dilantin), and carbamazepine (Tegretol) that are traditionally used in the treatment of seizure disorders. Amitriptyline (Elavil, Endep) and desipramine (Norpraminine) are medications that are traditionally used for depression. While many of these medications are not indicated specifically for the treatment of diabetes related nerve pain, they are used by physicians commonly.

The pain of diabetic nerve damage may also improve with better blood sugar control, though unfortunately blood glucose control and the course of neuropathy do not always go hand in hand. Newer medications for nerve pain include Pregabalin (Lyrica) and duloxetine (Cymbalta).  

What can be done to slow the complications of diabetes?

Findings from the Diabetes Control and Complications Trial (DCCT) and the United Kingdom Prospective Diabetes Study (UKPDS) have clearly shown that aggressive and intensive control of elevated levels of blood sugar in patients with type 1 and type 2 diabetes decreases the complications of nephropathy, neuropathy, retinopathy, and may reduce the occurrence and severity of large blood vessel diseases. Aggressive control with intensive therapy means achieving fasting glucose levels between 70-120 mg/dl; glucose levels of less than 160 mg/dl after meals; and a near normal hemoglobin A1c levels (see below).

Studies in type 1 patients have shown that in intensively treated patients, diabetic eye disease decreased by 76%, kidney disease decreased by 54%, and nerve disease decreased by 60%. More recently the EDIC trial has shown that type 1 diabetes is also associated with increased heart disease, similar to type 2 diabetes. However, the price for aggressive blood sugar control is a two to three fold increase in the incidence of abnormally low blood sugar levels (caused by the diabetes medications). For this reason, tight control of diabetes to achieve glucose levels between 70 to120 mg/dl is not recommended for children under 13 years of age, patients with severe recurrent hypoglycemia, patients unaware of their hypoglycemia, and patients with far advanced diabetes complications. To achieve optimal glucose control without an undue risk of abnormally lowering blood sugar levels, patients with type 1 diabetes must monitor their blood glucose at least four times a day and administer insulin at least three times per day. In patients with

type 2 diabetes, aggressive blood sugar control has similar beneficial effects on the eyes, kidneys, nerves and blood vessels.

What is the prognosis for a person with diabetes?

The prognosis of diabetes is related to the extent to which the condition is kept under control to prevent the development of the complications described in the preceding sections. Some of the more serious complications of diabetes such as kidney failure and cardiovascular disease, can be life-threatening. Acute complications such as diabetic ketoacidosis can also be life-threatening. As mentioned above, aggressive control of blood sugar levels can prevent or delay the onset of complications, and many people with diabetes lead long and full lives