EPIDEMIOLOGY OF CARDIOVASCULAR DISEASE (CVD) Public Health February 17, 2005 BETTINA PIKO, M.D., Ph.D.

EPIDEMIOLOGY OF EPIDEMIOLOGY OF CARDIOVASCULAR CARDIOVASCULAR

DISEASE (CVD)DISEASE (CVD)Public HealthPublic Health

February 17, 2005February 17, 2005

BETTINA PIKO, M.D., BETTINA PIKO, M.D., Ph.D.Ph.D.

„„Cardiovascular disease has Cardiovascular disease has the same meaning for health the same meaning for health

care today as the epidemics of care today as the epidemics of centuries had for medicine in centuries had for medicine in

earlier times: 50% of the earlier times: 50% of the population in developed population in developed

countries die of cardiovascular countries die of cardiovascular disease” (Pál Kertai)disease” (Pál Kertai)

Someone has a heart attack every Someone has a heart attack every two minutes (British Heart two minutes (British Heart

Foundation)Foundation)

Public Health Public Health SignificanceSignificance

• - Leading cause of mortality in developed - Leading cause of mortality in developed countries and a rising tendency in developing countries and a rising tendency in developing countries (disease of civilization)countries (disease of civilization)

• - A major impact on life expectancy - A major impact on life expectancy • - Significantly contributes to morbidity and death - Significantly contributes to morbidity and death

rates in the middle aged population: potential life rates in the middle aged population: potential life years lost, common cause of premature death, years lost, common cause of premature death, labor force (economic costs), family lifelabor force (economic costs), family life

• - Morbidity: nearly 30% of all disability cases- Morbidity: nearly 30% of all disability cases• - Contributes to deterioration of the quality of life- Contributes to deterioration of the quality of life

Types of Cardiovascular Types of Cardiovascular DiseaseDisease• - Coronary heart disease (CHD, ischemic heart - Coronary heart disease (CHD, ischemic heart

disease, heart attack, myocardial infarction, angina disease, heart attack, myocardial infarction, angina pectoris)pectoris)

• - Cerebrovascular disease (stroke, TIA, transient - Cerebrovascular disease (stroke, TIA, transient ischemic attack)ischemic attack)

• - Hypertensive heart disease- Hypertensive heart disease• - Peripheral vascular disease- Peripheral vascular disease• - Heart failure- Heart failure• - Rheumatic heart disease - Rheumatic heart disease (streptococcal infection)(streptococcal infection)

• - Congenital heart disease- Congenital heart disease• - Cardiomyopathies- Cardiomyopathies

Tasks of Cardiovascular EpidemiologyTasks of Cardiovascular Epidemiology

• - Detection of the occurrence and - Detection of the occurrence and distribution of CVD in populations, distribution of CVD in populations, surveillance, monitoring, trends of surveillance, monitoring, trends of changeschanges

• - Study of the natural history of CVD - Study of the natural history of CVD • - Formulation and testing of etiological - Formulation and testing of etiological

hypotheses (risk factors)hypotheses (risk factors)• - Contribution to the development of - Contribution to the development of

cardiovascular prevention programs cardiovascular prevention programs and the measurement of their and the measurement of their effectiveness effectiveness

Parts of Cardiovascular EpidemiologyParts of Cardiovascular Epidemiology• 1., Descriptive epidemiology:1., Descriptive epidemiology:• = Describing distribution of cardiovascular disease by = Describing distribution of cardiovascular disease by

means of certain characteristics such as : PERSON (i.e., means of certain characteristics such as : PERSON (i.e., age, gender, ethnicity) TIME and PLACEage, gender, ethnicity) TIME and PLACE

• 2., Analytic epidemiology2., Analytic epidemiology• = Analyzing relationships between CVD and risk factors = Analyzing relationships between CVD and risk factors

(which elevate the probability of a disease at population (which elevate the probability of a disease at population level), risk model and multicausal developmentslevel), risk model and multicausal developments

• 3., Experimental epidemiology/Interventions3., Experimental epidemiology/Interventions• = Strategies of cardiovascular prevention (primordial, = Strategies of cardiovascular prevention (primordial,

primary, secondary, tertiary; individual and community primary, secondary, tertiary; individual and community levels)levels)

Descriptive Epidemiology I. Descriptive Epidemiology I. Distribution Patterns in the Distribution Patterns in the

WorldWorld• In the world: CVD deaths account for one third of all In the world: CVD deaths account for one third of all deaths (25-50% depending on the level of economic deaths (25-50% depending on the level of economic development) among which 50%: coronary deathsdevelopment) among which 50%: coronary deaths

• CVD made up 16.7 million of global deaths in 2002, CVD made up 16.7 million of global deaths in 2002, among which 7 million due to coronary heart disease, 6 among which 7 million due to coronary heart disease, 6 million due to strokemillion due to stroke

• Distribution of types of CVD in global deaths :Distribution of types of CVD in global deaths :• Global cardiovascular deaths in 2002: 16.7 millionGlobal cardiovascular deaths in 2002: 16.7 million• among which: coronary heart disease 7.2 million > among which: coronary heart disease 7.2 million >

stroke 6.0 million > 0.9 million hypertensive heart stroke 6.0 million > 0.9 million hypertensive heart disease > 0.4 million inflammatory heart disease > 0.3 disease > 0.4 million inflammatory heart disease > 0.3 million rheumatic heart disease > 1.9 million other CVDmillion rheumatic heart disease > 1.9 million other CVD

Descriptive Epidemiology Descriptive Epidemiology II. AGEII. AGE

• Question: What is the relative amount of Question: What is the relative amount of CVD in death rates in different age groups?CVD in death rates in different age groups?

• - Early lesions of blood vessel, atherosclerotic - Early lesions of blood vessel, atherosclerotic plaques: around 20 years - adult lifestyle plaques: around 20 years - adult lifestyle patterns usually start in childhood and youth patterns usually start in childhood and youth (smoking, dietary habits, sporting behavior, etc.)(smoking, dietary habits, sporting behavior, etc.)

• - Increase in CVD morbidity and mortality: in - Increase in CVD morbidity and mortality: in age-group of 30-44 yearsage-group of 30-44 years

• - Premature death (<64 years of age, or 25-64 - Premature death (<64 years of age, or 25-64 years): in the elderly population more difficult to years): in the elderly population more difficult to interpret death rate due to multiple ill health interpret death rate due to multiple ill health causescauses

4,6%

11,4%

22,5%

61,5%

32,7%

26,9%

26,0%

14,0%

55,8%

24,6%

14,9%

4,7%

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

1-24 yrs 25-64 yrs >65 yrs

PROPORTION OF MORTALITY IN DIFFERENT AGE-GROUPS (MEN)

externalotherscancerCVD

7,3%

17,7%

35,0%

40,0%

31,3%

36,5%

24,0%

8,2%

64,7%

12,2%

18,3%

4,8%

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

1-24 yrs 25-64 yrs >65 yrs

PROPORTION OF MORTALITY IN DIFFERENT AGE-GROUPS (WOMEN)

externalothers

cancerCVD

Descriptive Epidemiology Descriptive Epidemiology III. SEXIII. SEX• Question: What is the relative amount of CVD in death rates in Question: What is the relative amount of CVD in death rates in

women and men?women and men?• - Widespread idea: CVD is often thought to be a disease of middle-- Widespread idea: CVD is often thought to be a disease of middle-

aged men. aged men. • - Cardiovascular mortality (fatal cases) are more common among - Cardiovascular mortality (fatal cases) are more common among

men. However, CVD affect nearly as many women as men, albeit at an men. However, CVD affect nearly as many women as men, albeit at an older ageolder age

• - Women: special case (WHO, 2004)- Women: special case (WHO, 2004)• a., Higher risk in women than men (smoking, high triglyceride levels)a., Higher risk in women than men (smoking, high triglyceride levels)• b., Higher prevalence of certain risk factors in women (diabetes b., Higher prevalence of certain risk factors in women (diabetes

mellitus, depression)mellitus, depression)• c., Gender-specific risk factors (risks for women only) (oral c., Gender-specific risk factors (risks for women only) (oral

contraceptives, hormone replacement therapy, polycystic ovary contraceptives, hormone replacement therapy, polycystic ovary syndrome)syndrome)

SDR, coronary heart disease in SDR, coronary heart disease in selected European countries by selected European countries by gender, 0-64 yrs, per 1000000gender, 0-64 yrs, per 1000000

Descriptive Epidemiology Descriptive Epidemiology IV. IV. ETHNICITYETHNICITY

• Question: What is the relative amount of CVD in Question: What is the relative amount of CVD in death rates in different ethnic groups?death rates in different ethnic groups?

• - In the US: increased cardiovascular disease deaths in - In the US: increased cardiovascular disease deaths in African-American and South-Asian populations in African-American and South-Asian populations in comparison with Whitescomparison with Whites

• - Increased stroke risk in African-American, some - Increased stroke risk in African-American, some Hispanic American, Chinese, and Japanese populationsHispanic American, Chinese, and Japanese populations

• - Migration: Ni-Hon-San Study: Japanese living in Japan - Migration: Ni-Hon-San Study: Japanese living in Japan had the lowest rates of CHD and cholesterol levels, had the lowest rates of CHD and cholesterol levels, those living in Hawaii had intermediate rates for both, those living in Hawaii had intermediate rates for both, those living in San Francisco had the highest rates for those living in San Francisco had the highest rates for bothboth

Descriptive Epidemiology V. Descriptive Epidemiology V. TIME and PLACE TIME and PLACE

• Question: What is the relative amount of Question: What is the relative amount of CVD in different geographical places? CVD in different geographical places? What are the time trends? International What are the time trends? International and regional characteristics of and regional characteristics of distributiondistribution

• SDR: Standardized Death RateSDR: Standardized Death Rate• Direct mode of standardization, using the Direct mode of standardization, using the

age distribution of a hypothetical age distribution of a hypothetical European standard populationEuropean standard population

• Premature death rates for comparison Premature death rates for comparison purposes (<64 years of age)purposes (<64 years of age)

Descriptive Epidemiology VI. Descriptive Epidemiology VI. World TrendsWorld Trends

• Developed countries: decreasing tendencies Developed countries: decreasing tendencies (e.g, USA: 30% between 1988-98, Sweden: 42%) (e.g, USA: 30% between 1988-98, Sweden: 42%)

• - improvement of lifestyle factors, for example, a - improvement of lifestyle factors, for example, a decrease of smoking and a higher level of health decrease of smoking and a higher level of health consciousness in many developed countriesconsciousness in many developed countries

• - better diagnostic and therapeutic procedures - better diagnostic and therapeutic procedures (e.g., bypass surgeries, hypertension screening, (e.g., bypass surgeries, hypertension screening, pharmacological treatment of hypertension and pharmacological treatment of hypertension and hypercholesterinaemia, access to health care)hypercholesterinaemia, access to health care)

• Developing countries: increasing tendenciesDeveloping countries: increasing tendencies• - increasing longevity, urbanization, and western - increasing longevity, urbanization, and western

type lifestyletype lifestyle

Descriptive Epidemiology Descriptive Epidemiology VII. International VII. International

ComparisonsComparisons

• Aims: Aims: • a., Where are the rates higher a., Where are the rates higher

or lower?or lower?• b., Interpretation of time b., Interpretation of time

trendstrends• c., Inequalities in c., Inequalities in

cardiovascular death cardiovascular death

Cardiovascular deaths in Cardiovascular deaths in Europe Europe

(SDR, 2000)(SDR, 2000)

SDR, diseases of circulatory SDR, diseases of circulatory system in Western Europe, 0-system in Western Europe, 0-

64 yrs, per 100000064 yrs, per 1000000

EU-15 averageEU-15 average

United KingdomUnited Kingdom         

SwitzerlandSwitzerland         

SpainSpain         

NetherlandsNetherlands         

ItalyItaly         

GreeceGreece         

FranceFrance         

FinlandFinland         

DenmarkDenmark         

AustriaAustria         

SDR, diseases of circulatory SDR, diseases of circulatory system in Eastern Europe, 0-64 system in Eastern Europe, 0-64

yrs, per 1000000yrs, per 1000000

EU-15 EU-15 average average

(MSs prior (MSs prior 1.5.2004)1.5.2004)

SlovakiSlovakiaa

Russian Russian FederationFederation

RomanRomaniaia

HungarHungaryy

CroatiaCroatia                     

SDR, diseases of circulatory SDR, diseases of circulatory system in Hungary, 0-64 yrs, system in Hungary, 0-64 yrs,

per 1000000per 1000000

         FinlandFinland

         HungaryHungary

EU-15 EU-15 averageaverage

Analytic Epidemiology I. Analytic Epidemiology I. Role of Risk FactorsRole of Risk Factors

• Over 300 risk factors have been associated with Over 300 risk factors have been associated with coronary heart disease, hypertension and strokecoronary heart disease, hypertension and stroke

• Approx. 75% of CVD can be attributed to Approx. 75% of CVD can be attributed to conventional risk factorsconventional risk factors

• Risk factors of great public health significance:Risk factors of great public health significance:• - high prevalence in many populations- high prevalence in many populations• - great independent impact on CVD risk- great independent impact on CVD risk• - their control and treatment result in reduced CVD risk- their control and treatment result in reduced CVD risk• Developing countries: double burden of risks (problems Developing countries: double burden of risks (problems

of undernutrition and infections + CVD risks)of undernutrition and infections + CVD risks)

Analytic Epidemiology II. Analytic Epidemiology II. Classification of Risk FactorsClassification of Risk Factors

Major modifiable risk factors- High blood pressure- Abnormal blood lipids- Tobacco use- Physical inactivity- Obesity- Unhealthy diet- Diabetes mellitus

Other modifiable risk factors - Low socioeconomic status - Mental ill health (depression)- Psychosocial stress- Heavy alcohol use- Use of certain medication- Lipoprotein(a)

Non-modifiable risk factors- Age- Heredity or family history- Gender- Ethnicity or race

”Novel” risk factors- Excess homocysteine in blood- Inflammatory markers (C-

reactive protein)- Abnormal blood coagulation

(elevated blood levels of fibrinogen)

Analytic Epidemiology III. Analytic Epidemiology III. HypertensionHypertension

• - Systolic blood pressure >140 Hgmm and/or a - Systolic blood pressure >140 Hgmm and/or a diastolic blood pressure > 90 Hgmm diastolic blood pressure > 90 Hgmm

• - Free of clinical symptoms for many years (screening) - Free of clinical symptoms for many years (screening) • - In most countries, up to 30 percent of adults - In most countries, up to 30 percent of adults

suffering, increasing with age in civilized countriessuffering, increasing with age in civilized countries• - Positive family history- Positive family history• - Dietary habits (a high intake of salt, processed food, - Dietary habits (a high intake of salt, processed food,

low levels of water hardness, high thyramine content low levels of water hardness, high thyramine content of food, alcohol use)of food, alcohol use)

• - Modern lifestyle (increased sympathetic activity, - Modern lifestyle (increased sympathetic activity, psychosocial stress, leading position in job)psychosocial stress, leading position in job)

Analytic Epidemiology IV. Analytic Epidemiology IV. Rheumatic Fever and Rheumatic Heart Rheumatic Fever and Rheumatic Heart

DiseaseDisease• Development: Rheumatic fever usually follows an Development: Rheumatic fever usually follows an

untreated beta-haemolytic streptococcal throat untreated beta-haemolytic streptococcal throat infection in childreninfection in children

• As a consequence, the heart valves are permanently As a consequence, the heart valves are permanently damaged which may progress to heart failuredamaged which may progress to heart failure

• Today mostly affects children in developing countries, Today mostly affects children in developing countries, linked to poverty, inadequacy of health care accesslinked to poverty, inadequacy of health care access

• Occurrence: 12 million people currently affected by Occurrence: 12 million people currently affected by rheumatic fever and RHD, two-thirds are children (5-15 rheumatic fever and RHD, two-thirds are children (5-15 years), for example: approx. 1 000 000 in Sub-Saharan years), for example: approx. 1 000 000 in Sub-Saharan Africa, 700 000 in South-Central Asia, 176 000 in China, Africa, 700 000 in South-Central Asia, 176 000 in China, 150 000 in North Africa, 40 000 in Eastern Europe (!)150 000 in North Africa, 40 000 in Eastern Europe (!)

Analytic Epidemiology V. Analytic Epidemiology V. Abnormal Blood Lipids Abnormal Blood Lipids

• - Se cholesterol: structure and - Se cholesterol: structure and functioning of blood vessels, functioning of blood vessels, atherosclerotic plaquesatherosclerotic plaques

• - Altering functions of cholesterol - Altering functions of cholesterol fractions (LDL: risk, HDL: protection)fractions (LDL: risk, HDL: protection)

• - Estrogen: tends to raise HDL-- Estrogen: tends to raise HDL-cholesterol and lower LDL-cholesterol, cholesterol and lower LDL-cholesterol, protection for women in reproductive ageprotection for women in reproductive age

• - Partially genetic determination of - Partially genetic determination of metabolism, partially dependent of metabolism, partially dependent of nutrition (egg, meats, dairy products)nutrition (egg, meats, dairy products)

Current Recommended Current Recommended Lipid LevelsLipid LevelsEuropean guidelines

US guidelines

Total cholesterol <5.0 mmol/l <240 mg/dl (6.2 mmol/l)

LDL-cholesterol <3.0 mmol/l <160 mg/dl (3.8 mmol/l)

HDL-cholesterol >=1.0 mmol/l (men)>=1.2 mmol/l (women)

>=40 mg/dl (1 mmol/l)

Triglycerides (fasting)

<1.7 mmol/l <200 mg/dl (2.3 mmol/l)

Analytic Epidemiology VI. Analytic Epidemiology VI. Tobacco UseTobacco Use

• - The link between smoking and CVD (mainly CHD) - The link between smoking and CVD (mainly CHD) was identified in 1940was identified in 1940

• - Greatest risk: initiation < 16 years- Greatest risk: initiation < 16 years• - Passive smoking: additional risk- Passive smoking: additional risk• - Women smokers: are at higher risk of CHD and CVD - Women smokers: are at higher risk of CHD and CVD

than male smokers than male smokers • - Several mechanisms: damages the endothelium - Several mechanisms: damages the endothelium

lining, increases atherosclerotic plaques, raises LDL lining, increases atherosclerotic plaques, raises LDL and lowers HDL, promotes artery spasms, raises oxigen and lowers HDL, promotes artery spasms, raises oxigen demand of the heart muscledemand of the heart muscle

• - Nicotine accelerates the heart rate (RR), and raises - Nicotine accelerates the heart rate (RR), and raises blood pressureblood pressure

Analytic Epidemiology VII. Analytic Epidemiology VII. Physical Inactivity Physical Inactivity

• - Regular physical activity: protective factor- Regular physical activity: protective factor• - Intensity and duration (150 minutes/week - Intensity and duration (150 minutes/week

intermediate or 60 minutes/week heavy)intermediate or 60 minutes/week heavy)• - Modernization, urbanization, mechanized transport: - Modernization, urbanization, mechanized transport:

sedentary lifestyle (60% of global population)sedentary lifestyle (60% of global population)• - Raises CVD risk and also the development of other - Raises CVD risk and also the development of other

risk factors (glucose metabolism, diabetes mellitus, risk factors (glucose metabolism, diabetes mellitus, blood coagulation, obesity, high blood pressure, blood coagulation, obesity, high blood pressure, worsening lipid profile)worsening lipid profile)

• - Physical activity: helps reduce stress, anxiety and - Physical activity: helps reduce stress, anxiety and depressiondepression

Analytic Epidemiology VIII. Analytic Epidemiology VIII. Obesity, Diabetes Mellitus, Unhealthy Obesity, Diabetes Mellitus, Unhealthy

DietDiet • - Body Mass Index: > 25: overweight, > 30: obesity- Body Mass Index: > 25: overweight, > 30: obesity• - A modern ”epidemic”: More than 60% of adults in - A modern ”epidemic”: More than 60% of adults in

the US are overweight or obese, in China: 70 the US are overweight or obese, in China: 70 million overweight people million overweight people

• - Elevates the risk of both CVD and diabetes - Elevates the risk of both CVD and diabetes mellitusmellitus

• - Diabetes mellitus: damages both peripheral and - Diabetes mellitus: damages both peripheral and coronary blood vesselscoronary blood vessels

• -Unhealthy diet: low fruit and vegetable, fiber -Unhealthy diet: low fruit and vegetable, fiber content, and high saturated fat intake, refined content, and high saturated fat intake, refined sugarsugar

Analytic Epidemiology IX. Analytic Epidemiology IX. Psychological and social Psychological and social

factorsfactors• - Psychological factors (Type A behavior, - Psychological factors (Type A behavior,

hostility)hostility)• - Depression and CVD: bidirectional link- Depression and CVD: bidirectional link• a., depression may increase the risk of CVD and a., depression may increase the risk of CVD and

worsen recovery process worsen recovery process • b., CVD may induce depression b., CVD may induce depression • - Low socioeconomic status (SES): - Low socioeconomic status (SES): • a., in developed countries: less educated and lower a., in developed countries: less educated and lower

SES groups (accumulation of risk factors)SES groups (accumulation of risk factors)• b., in developing countries: more educated and b., in developing countries: more educated and

higher SES groups (western lifestyle)higher SES groups (western lifestyle)

Cardiovascular Prevention I.Cardiovascular Prevention I.• PrimordialPrimordial: Social, legal and other (often nonmedical) : Social, legal and other (often nonmedical)

activities which may lead to a lowering of risk factors (e.g., activities which may lead to a lowering of risk factors (e.g., socioeconomic development, smoke-free restaurants)socioeconomic development, smoke-free restaurants)

• Primary:Primary: Controlling risk factors contributing to CVD Controlling risk factors contributing to CVD (health education programs, anti-smoking campaign, (health education programs, anti-smoking campaign, sports programs, nutrition counselling, regular check of sports programs, nutrition counselling, regular check of blood pressure and certain blood parameters, e.g., blood pressure and certain blood parameters, e.g., cholesterol, blood lipids, glucose)cholesterol, blood lipids, glucose)

• SecondarySecondary: Screening and treatment of symptomatic : Screening and treatment of symptomatic patients, set up personal risk profile patients, set up personal risk profile

• Tertiary:Tertiary: Cardiovascular rehabilitation, prevention of Cardiovascular rehabilitation, prevention of recurrence of CVD (new heart attack: 5-7 times higher risk recurrence of CVD (new heart attack: 5-7 times higher risk among CVD patients)among CVD patients)

Cardiovascular Prevention Cardiovascular Prevention II.II.• The individual approachThe individual approach (detecting those at greatest risk): (detecting those at greatest risk):

lifestyle guidelines (e.g., smoking cessation)lifestyle guidelines (e.g., smoking cessation)• The population-wide approach:The population-wide approach: (the whole population, (the whole population,

western lifestyle )western lifestyle )• Example for community-wide CV prevention programs:Example for community-wide CV prevention programs:• - Framingham Heart Study (1948-) Framingham Risk - Framingham Heart Study (1948-) Framingham Risk

ScoringScoring• - North-Karelia Project (1972-) Finland- North-Karelia Project (1972-) Finland• - Stanford Projects (1972-75, 1980-86) USA- Stanford Projects (1972-75, 1980-86) USA• - Minnesota Cardiovascular Health Program (1980-88) USA- Minnesota Cardiovascular Health Program (1980-88) USA• - Multiple Risk factor Intervention Trial (1972-79) USA- Multiple Risk factor Intervention Trial (1972-79) USA