Epidemiology of hypertension

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HYPERTENSION

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A SILENT

KILLER

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Hypertension is a silent, invisible killer that rarely causes symptoms. Increasing public awareness is key, as is access to early detection. Raised blood pressure is a serious warning sign that significant lifestyle changes are urgently needed. People need to know why raised blood pressure is dangerous, and how to take steps to control it

Dr Margaret Chan

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Hypertension is defined as a systolic blood pressure equal to or above 140 mm Hg and/or diastolic blood pressure equal to or above 90 mm Hg

HOW HYPERTENSION IS DEFINED ?

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History of

HypertensionHistory of

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Historical of hypertension records as far back as 2600 B.C. hold mention of “hard pulse disease”

First treatments: Leeching/phlebotomy, acupuncture

Hippocrates recommended phlebotomy 120 AD – cupping of the spine to draw

animal spirits down and out was recommended

History of Hypertension

9 Lithograph showing the leeching of a patient.

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No way to measure prior to 1700s

cupping of the spine

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1733 – Reverend Stephen Hales measured the intra-

1733 – Reverend Stephen Hales measured the intra-arterial BP of a horse

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1905 – N.C. Korotkoff reported on the method of auscultation of brachial artery, the method which is widely used today

Allowed auscultation of diastolic BP as well

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CATEGORY SYSTOLIC (mmHg)

DIASTOLIC (mmHG)

Optimal Normal Grade 1 Grade 2 Hypertension Grade 3 Hypertension ("severe")Isolated Systolic Hypertension 

<120 <130 140-159 160-179 >180>140 

<80 <85 > 90-99 >100-109 >110<90 

WHO/ISH CLASSIFICATION OF BLOOD PRESSURE

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CLASSIFICATION*

Normal <120 and <80

Prehypertension 120–139 or 80–89

Stage 1 Hypertension 140–159 or 90–99

Stage 2 Hypertension >160 or >100

Isolated systolic hypertension

>140 - <90

BP Classification SBP mmHg DBP mmHg

*JNC-7

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Seated quietly for 5 minutes Appropriate size cuff Inflate 20-30 mmHg above loss of radial

pulse.Deflate at 2mmHg per second 1st sound SBP ; Disappearance of

Korotkoff sound (phase 5) is DBP. – Confirm Elevated blood pressure within

2months(stage 1) –shorter for stage 2 if new onset

BP MEASUREMENT

*JNC-7

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Globally cardiovascular disease accounts for approximately 17 million deaths a year, nearly one third of the total deaths. Of these, complications of hypertension account for 9.4 million deaths worldwide every year .

Hypertension is responsible for at least 45% of deaths due to heart disease and 51% of deaths due to stroke .

WHY HYPERTENSION IS A MAJOR PUBLIC

HEALTH ISSUE?

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In terms of attributable deaths, hypertension is one of the leading behavioral and physiological risk factor to which 13% of global deaths are attributed.

Hypertension is reported to be the fourth contributor to premature death in developed countries and the seventh in developing countries.

CONTD..

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Recent reports indicate that nearly 1 billion adults (more than a quarter of the world’s population) had hypertension in 2000, and this is predicted to increase to 1.56 billion by 2025.

Today, mean blood pressure remains very high in many African and some European countries. The prevalence of raised blood pressure in 2008 was highest in the WHO African Region at 36.8% .

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Global Burden of Hypertension2025 Projection

26.4% of world adult population had hypertension

Total of 972 million adults

Highest prevalence is in established market economies (eg, North America, Europe)

• 29.2% of world adult population will have hypertension

• Total of 1.56 billion adults 20 % in developed nations, 80% in developing nations)

• Highest prevalence will be in developing continents (eg, Asia, Africa) will account for 75% of world’s hypertensive patients

Year 2000 Year 2025

Kearney PM et al. Lancet. 2005;365:217-223.

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12-74

IHD-mortalityRates( WHO-2008)

CVA mortalityRates( WHO-2008.)

75-108109-151

Data

12-7475-108109-151152-405Data not available

12-7475-108109-151152-405Data not available

A global brief on hypertension | Why hypertension is a major public health issue | I

Figure 01

Figure 02

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Recent studies from India have shown the prevalence of HTN to be 25% in urban and 10% in rural people in India .

According to the WHO estimates , the prevalence of raised BP in Indians is 32.5% (33.2% in men and 31.7% in women) .

Andhra Pradesh (13.3%), Odisha (9%), Chhattisgarh (8.4%) and Gujarat (6.7%) have highest prevalence while Assam and Rajasthan (1.4%), Kerala (2.4%), Bihar (2.7%), Madhya Pradesh (2.8%) and Uttar Pradesh (3.6%) are low prevalence states.

Journal of Hypertension:June 2014 - Volume 32 - Issue 6 - p 1170–1177*

INDIAN SCENARIO*

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Despite the high prevalence; prevention, detection, treatment, and control of hypertension is still suboptimal indeveloping countries like India

Rule of halves’ states that ‘half of hypertensive patients remain undiagnosed, half of known do not receive treatment and half of treated, do not achieve adequate control.

RULE OF HALVES

JAPI • VOL. 51 • FEBRUARY 2003

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Primary (Essential) Hypertension

- Elevated BP with unknown cause - 90% to 95% of all cases

Secondary Hypertension - Elevated BP with a specific

cause - 5% to 10% in adults

CLASSIFICATION OF HYPERTENSION

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NON-MODIFIABLE

Age (> 55 for men; > 65 for women) Gender Family history Ethnicity (African Americans)

Risk Factors for PrimaryHypertension

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a) Alcoholb) Cigarette smokingc) Diabetes mellitusd) Elevated serum lipidse) Excess dietary sodiumf) Obesity (BMI > 30)g) Sedentary lifestyleh) Socioeconomic statusi) Stress

MODIFIABLE

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Frequently asymptomatic until severe and target organ disease has occurred

Fatigue, reduced activity tolerance Dizziness/Headache Palpitations, Angina Dyspnoea

Clinical Manifestations

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§ Sleep apnea§ Drug-induced or related causes§ Chronic kidney disease§ Primary aldosteronism§ Renovascular disease§ Chronic steroid therapy and Cushing’s

syndrome§ Pheochromocytoma§ Coarctation of the aorta§ Thyroid or parathyroid disease

Identifiable Causes of Hypertension

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Etiology and pathogenesis

The

pathogenesis of primary hypertension is still unclear.

There are many factors associated with it.

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a. Genetic factorsb. Sodium intakec. Renin- agiotensin

systemsd. Sympathetic nervous

systeme. Endothelial dysfunctionf. Insulin resistanceg. Other factors

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Genetic factors

The off springs of the hypertensive parents are more prone to suffer from essential hypertension compared with that without hypertensive family.

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Sodium intake The mechanisms

leading to hypertension are due to increased blood volume and the content of the sodium in the smooth muscle cells enhance following subsequent calcium increase.

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Sympathetic nervous activation

The activation of Sympathetic nervous can augment periphery resistant which

increase systemic arterial pressure.

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Other factors

Obesity Smoking Intake alcohol OSAS Low calcium , magnesium and potassium.

(Obstructive Sleep Apnea Syndrome)

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Pathology

Systemic atherosclerosis develops with increased intimal-medium thickness leading to ischemic alterations in target organs such as heart, brain, kidney and peripheral artery.

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Blood vessel change

In Aorta and large arteries recurrent pulsatile stress produces uncoiling, disruption and calcification of elastic fibres. At the same time, relatively inelastic collagen is also increased.

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Contd…

This is a result of ageing as well as hypertension : both processes therefore cause loss of the normal elastic reservoir funtion of arteries.

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Hypertensive Heart Disease/ Coronary artery disease Left ventricular hypertrophy/ Heart failure Cerebro-vascular Disease/ Stroke Peripheral Vascular Disease Nephrosclerosis/nephropathies Retinal Damage Hypertensive emergencies Dissection of aorta

Complications

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§ Routine Tests• Electrocardiogram • Urinalysis / Blood glucose, and hematocrit • Serum potassium, creatinine, or the corresponding

estimated GFR, and calcium• Lipid profile, after 9- to 12-hour fast, that includes high-

density and low-density lipoprotein cholesterol, and triglycerides

§ Optional tests - Measurement of urinary albumin excretion or albumin/creatinine ratio

§ More extensive testing for identifiable causes is not generally indicated unless BP control is not being achieved.

Laboratory examinations

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JNC-8 :TREATMENT CHOICES

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PREVENTION OF

HTN

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Hypertension can be prevented by complementary application of strategies that target the general population and individuals and groups at higher risk for high blood pressure.

However, prevention strategies applied early in life provide the greatest long-term potential for reducing the overall burden of blood pressure related complications in the community

Approaches to Primary Preventionof Hypertension

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A population-based approach aimed at achieving a downward shift in the distribution of blood pressure in the general population and is an important component for any comprehensive plan to prevent hypertension.

A small decrement in systolic blood pressure is likely to result in a substantial reduction in the burden of blood pressure-related illness

POPULATION-BASED STRATEGY

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Average Percent Reduction

Stroke incidence 35–40%

Myocardial infarction 20–25%

Heart failure 50%

Benefits of Lowering BP

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In an analysis based on Framingham Heart Study experience, Cook et al. concluded that a 2 mmHg reduction in the population average of diastolic blood pressure for white U.S. residents 35 to 64 years of age would result in a 17 percent decrease in the prevalence of hypertension, a 14 percent reduction in the risk of stroke and transient ischemic attacks, and a 6 percent reduction in the risk of CHD

Framingham Heart Study

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BP Reductions as Small as 2 mmHg Reduces the Risk of CV Events by Up to 10%

▶ Meta-analysis of 61 prospective, observational studies

▶ 1 million adults ▶ 12.7 million person-years 10% increase in risk

stroke Mortality

2 mmHg increase in mean SBP 7% increase in risk of IHD Mortality

Reduction as Small as 2 mmHg reduces the Risk of CV Events by Up to 10%

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Public health approaches, such as lowering sodium content or caloric density in the food supply, and providing attractive, safe, and convenient opportunities for exercise are ideal population-based approaches for reduction of average blood pressure in the community

Public health approaches

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More intensive targeted approaches, aimed at achieving a greater reduction in blood pressure in those

who are most likely to develop hypertension.

Groups at high risk for hypertension include those with a grade –I blood pressure, a family history of hypertension, overweight or obesity, smokers,a sedentary lifestyle, excess intake of dietary sodium and/or insufficient intake of potassium, and/or excess consumption of alcohol.

INTENSIVE TARGETED STRATEGY

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Hypertension and Sodium

The Connection

Excess Sodium Intake Leads to Hypertension

Sodium, through hypertension, is a major contributor to death, disability, disparities, and costs attributable to cardiovascular diseases (CVD)

Globally, 8.5 million deaths could be averted over 10 years from 2006 to 2015 through a 15% reduction in sodium intake

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An adults should consume less than 2000 milligrams of sodium, or 5 g of salt per day

Sodium content is high in processed foods, such as bread (approximately 250 mg/100 g), processed meats like bacon (approximately 1500 mg/100 g), and popcorn (approximately 1500 mg/100 g), as well as in condiments such as soy sauce (approximately 7000 mg/100 g), and bouillon or stock cubes (approximately 20 000 mg/100 g).

WHO recommendations

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WHO recommends that adults should consume at least 3,510 mg of potassium/day.

Potassium-rich foods include :

beans and peas (approximately 1,300 mg of potassium per 100 g), nuts (approximately 600 mg/100 g), vegetables such as spinach, cabbage and parsley (approximately 550 mg/100 g) and fruit such as bananas, (approximately 300 mg/100 g).

Potassium-rich food helps to reduce blood pressure

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How public health stakeholders

can tackle hypertension?

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There are six important components of any country

1|an integrated primary care programme 2|the cost of implementing the programme 3|basic diagnostics and medicines 4|reduction of risk factors in the population 5|workplace-based wellness programmes 6|monitoring of progress.

Initiative To Address Hypertension

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Integrated programmes must be established at the primary care level for control of hypertension. In most countries this is the weakest level of the health system.

Treatment should be targeted particularly at people at medium or high risk of developing heart attack, stroke or kidney damage.

The features of an integrated primary care programme

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The cumulative cost of implementing an integrated primary care programme to prevent heart attack, stroke and kidney failure, using blood pressure as an entry point that address cardiovascular disease and cervical cancer in all low- and middle-income countries is estimated to be US$ 9.4 billion a year

1. Cost of implementing an integrated primary care programme

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Availability of basic technologies to manage people with hypertension .

Availability and appropriate use of essential medicines to prevent complications in people with moderate to high cardiovascular risk .

The links between different levels of the health system so that people can be managed appropriately based on heir level of risk.

2. A WHO costing tool to estimate the cost of establishing such a programme

in any country

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The basic diagnostic technologies requiredfor addressing hypertension include accurate blood pressure measurement devices,weighing scales, urine albumin strips, fastingblood sugar tests and blood cholesterol tests.

3. Basic diagnostics and medicines

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Not all patients diagnosed with hypertensionrequire medication but those at medium tohigh risk will need one or more of eight essen-tial medicines to lower their cardiovascularrisk.

A thiazide diuretic, an angiotensin convertingenzyme inhibitor, a long-acting calcium chan-nel blocker, a beta blocker, metformin, insulin,a statin and aspirin).

Contd….

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The cost of implementing such a programme is low, at less than US$ 1 per head in low-income countries, less than US$ 1.50 per head in lower middle-income countries and US$ 2.50 in up- per middle-income countries

Contd….

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Most cardiovascular disease in the population occurs in people with an average risk level, because they constitute the largest proportion of the population.

The population-based approach is thus based on the observation that effective reduction of cardiovascular disease rates in the population usually calls for community-wide changes in unhealthy behaviors or reduction in mean risk factor levels.

4 . Reduction of risk factors in the population

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Population-wide approaches to reduce high blood pressure are similar to those that address other major non communicable diseases.

They require public policies to reduce the exposure of the whole population to risk factors such as an unhealthy diet, physical inactivity, harmful use of alcohol and tobacco use , with a special focus on children, adolescents and youth.

Contd…

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WHO considers work place health programmes to be one of the most cost-effective

Workplace wellness programmes should focus on promoting worker health through the reduction of individual risk-related behaviours, e.g. tobacco use, unhealthy diet, harmful use of alcohol, physical inactivity and other health risk behaviors

5 Workplace wellness programmes

and high blood pressure control

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National surveillance health information systems must be strengthened to monitor the impact of action to prevent and control hypertension and other risk factors of non communicable diseases.

Monitoring systems must collect reliable information on risk factors and their determinants, non communicable disease mortality and illness. This data is critical for policy and programme development. However, some countries still lack surveillance data for hypertension and other risk factors

6. Monitoring the impact of actionto tackle hypertension

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National Programme for Prevention and Control of Diabetes, Cardiovascular Diseases and Stroke (NPDCS) was launched on 4th Jan 2008

Objectives

1. Risk reduction for prevention of NCDs (Diabetes, CVD and Stroke)

2. Early diagnosis and appropriate management of Diabetes, Cardiovascular Diseases,cancer and Stroke

National Programme For Prevention and Control of Cancer, Diabetes, Cardiovascular Disease and Stroke(NPCDCS)

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1. Health Promotion for the General Population

2. Disease Prevention for the High Risk groups.

Community Based Interventions, Workplace

Interventions , Disease Prevention for the High Risk, Setting up special clinics , Harnessing the Private Sector and Specific interventions at the tertiary level to enhance capacity to respond to the needs of NCD

Strategies

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Awareness generated on HEALTHY LIFE STYLES.

Decrease in the incidence of Non –Communicable Diseases particularly, Diabetes, Cardiovascular Diseases,cancer and Stroke.

Expected outcomes

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A. At Sub centre

1.Health promotion for behavior change

2.‘Opportunistic’ Screening using B.P measurement and blood glucose by strip method

3. Referral of suspected cases to CH

Packages of services to be made available at different levels under NPCDCS

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1. Prevention and health promotion including counseling

2.Early diagnosis through clinical and laboratory investigations (Common lab investigations: Blood Sugar, lipid profile, ECG, Ultrasound, X ray etc.)

3. Management of common CVD, diabetes and stroke cases(out patient and in patients.)

4. Home based care for bed ridden chronic cases

5. Referral of difficult cases to District Hospital/higher health care facilit

At C.H.C.

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1. Investigations: Blood Sugar, lipid profile, Kidney Function Test (KFT),Liver Function Test ( LFT), ECG, Ultrasound, X ray, colonscopy , mammography etc. (if not available, will be outsourced)

2. Medical management of cases ( out patient , inpatient and intensive Care )

3.Follow up and care of bed ridden cases

4.Day care facility

District Hospital

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A combination of increased physical activity, moderation in alcohol intake, and consumption of an eating plan that is lower in sodium content and higher in fruits, vegetables and low fat dairy products represents the best approach for preventing high blood pressure in the general population and in high risk groups.

KEY MESSAGE

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a. For persons over age 50, SBP is a more important than DBP as CVD risk factor.

b. Starting at 115/75 mmHg, CVD risk doubles with each increment of 20/10 mmHg throughout the BP range.

c. Persons who are normotensive at age 55 have a 90% lifetime risk for developing HTN.

d. Those with SBP 120–139 mmHg or DBP 80–89 mmHg should be considered prehypertensive who require health-promoting lifestyle modifications to prevent CVD.

Take Home Message

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1. WHO. A global brief on hypertension. World Health Day 2013.

2. Community Medicines with Recent Advances by A H Suryakantha.Third Edition-2014.

3. The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES , August 2004.

4. Primary Prevention of Hypertension: Clinical and Public Health Advisory from the National High Blood Pressure Education Program. NIH PUBLICATION NO. 02-5076 NOVEMBER 2002.

REFERENCES

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5. A short history of blood pressure measurement. Proc R Soc Med. Nov 1977; 70(11): 793–799. http://www.ncbi. nlm. nih.gov/pmc/articles/PMC1543468.

6. The Updated WHO/ISH Hypertension Guidelines. Linda Brookes.  Medscape Mar 16, 2004. http://www.medscape. com/ viewarticle/471863.

7. 2014 Evidence-Based Guideline for the Management of High Blood Pressure in AdultsReport From the Panel Members Appointed to the Eighth Joint National Committee (JNC 8) .

8. AMA. 2014;311(5):507-520. doi:10.1001/jama. 2013.284427.

CONTD....

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9. Kearney PM et al. Global burden of hypertension: analysis of worldwide data. Lancet. 2005 Jan 15-21;365(9455):217-23.

10. Journal of Hypertension: June Volume 32 - Issue 6 - p 1170–1177.

11. Anchala, Raghupathy et al.Hypertension in India: a systematic review and meta-analysis of prevalence, awareness, and control of hypertension. Journal of Hypertension:June 2014 - Volume 32 - Issue 6 - p 1170–1177.

12. Gupta R. Trends in hypertension epidemiology in India. J Hum Hypertens 2004; 18:73–78.

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13. NATIONAL PROGRAMME FOR PREVENTION AND CONTROL OF CANCER,DIABETES, ARDIOVASCULAR DISEASES & STROKE ,(NPCDCS),2004 14. R Deepa et al.Is the ‘Rule of Halves’ in Hypertension Still Valid?

-Evidence from the Chennai Urban Population Study. JAPI • VOL. 51 • FEBRUARY 2003.

15. Institute of Medicine. Dietary reference intakes for water, potassium, sodium chloride, and sulfate. Washington, DC: National Academies Press; 2004.

16. The Framingham Heart Study’s Impact on Global Risk Assessment. Asaf Bitton, Thomas Gaziano Prog Cardiovasc Dis. Author manuscript; available in PMC 2011 July 1.

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