EPIDEMIOLOGY%20OF%20CARDIOVASCULAR%20DISEASE%20(CVD)

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EPIDEMIOLOGY OF CARDIOVASCULAR DISEASE (CVD)
Public Health BETTINA PIKO, M.D., Ph.D.
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Cardiovascular disease has the same meaning for
health care today as the epidemics of centuries
had for medicine in earlier times 50 of the
population in developed countries die of
cardiovascular disease (Pál Kertai) Someone
has a heart attack every two minutes (British
Heart Foundation)
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Public Health Significance

• - Leading cause of mortality in developed
  countries and a rising tendency in developing
  countries (disease of civilization)
• - A major impact on life expectancy
• - Significantly contributes to morbidity and
  death rates in the middle aged population
  potential life years lost, common cause of
  premature death, labor force (economic costs),
  family life
• - Morbidity nearly 30 of all disability cases
• - Contributes to deterioration of the quality of
  life

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Types of Cardiovascular Disease

• - Coronary heart disease (CHD, ischemic heart
  disease, heart attack, myocardial infarction,
  angina pectoris)
• - Cerebrovascular disease (stroke, TIA, transient
  ischemic attack)
• - Hypertensive heart disease
• - Peripheral vascular disease
• - Heart failure
• - Rheumatic heart disease (streptococcal
  infection)
• - Congenital heart disease
• - Cardiomyopathies

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Tasks of Cardiovascular Epidemiology

• - Detection of the occurrence and distribution of
  CVD in populations, surveillance, monitoring,
  trends of changes
• - Study of the natural history of CVD
• - Formulation and testing of etiological
  hypotheses (risk factors)
• - Contribution to the development of
  cardiovascular prevention programs
  and the measurement of their
  effectiveness

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Parts of Cardiovascular Epidemiology

• 1., Descriptive epidemiology
• Describing distribution of cardiovascular
  disease by means of certain characteristics such
  as PERSON (i.e., age, gender, ethnicity) TIME
  and PLACE
• 2., Analytic epidemiology
• Analyzing relationships between CVD and risk
  factors (which elevate the probability of a
  disease at population level), risk model and
  multicausal developments
• 3., Experimental epidemiology/Interventions
• Strategies of cardiovascular prevention
  (primordial, primary, secondary, tertiary
  individual and community levels)

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Descriptive Epidemiology I. Distribution
Patterns in the World

• In the world CVD deaths account for one third of
  all deaths (25-50 depending on the level of
  economic development) among which 50 coronary
  deaths
• CVD made up 16.7 million of global deaths in
  2002, among which 7 million due to coronary heart
  disease, 6 million due to stroke
• Distribution of types of CVD in global deaths
• Global cardiovascular deaths in 2002 16.7
  million
• among which coronary heart disease 7.2 million gt
  stroke 6.0 million gt 0.9 million hypertensive
  heart disease gt 0.4 million inflammatory heart
  disease gt 0.3 million rheumatic heart disease gt
  1.9 million other CVD

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Descriptive Epidemiology II. AGE

• Question What is the relative amount of CVD in
  death rates in different age groups?
• - Early lesions of blood vessel, atherosclerotic
  plaques around 20 years - adult lifestyle
  patterns usually start in childhood and youth
  (smoking, dietary habits, sporting behavior,
  etc.)
• - Increase in CVD morbidity and mortality in
  age-group of 30-44 years
• - Premature death (lt64 years of age, or 25-64
  years) in the elderly population more difficult
  to interpret death rate due to multiple ill
  health causes

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PROPORTION OF MORTALITY IN DIFFERENT AGE-GROUPS
(MEN)
4,7
100
14,0
14,9
90
80
26,0
61,5
24,6
70
external
60
others
cancer
26,9
50
CVD
40
55,8
22,5
30
32,7
20
11,4
10
4,6
0
1-24 yrs
25-64 yrs
gt65 yrs
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PROPORTION OF MORTALITY IN DIFFERENT AGE-GROUPS
(WOMEN)
4,8
100
8,2
18,3
90
40,0
24,0
80
12,2
70
external
60
others
36,5
50
cancer
35,0
CVD
40
64,7
30
20
17,7
31,3
10
7,3
0
1-24 yrs
25-64 yrs
gt65 yrs
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Descriptive Epidemiology III. SEX

• Question What is the relative amount of CVD in
  death rates in women and men?
• - Widespread idea CVD is often thought to be a
  disease of middle-aged men.
• - Cardiovascular mortality (fatal cases) are more
  common among men. However, CVD affect nearly as
  many women as men, albeit at an older age
• - Women special case (WHO, 2004)
• a., Higher risk in women than men (smoking, high
  triglyceride levels)
• b., Higher prevalence of certain risk factors in
  women (diabetes mellitus, depression)
• c., Gender-specific risk factors (risks for women
  only) (oral contraceptives, hormone replacement
  therapy, polycystic ovary syndrome)

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SDR, coronary heart disease in selected European
countries by gender, 0-64 yrs, per 1000000
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Descriptive Epidemiology IV. ETHNICITY

• Question What is the relative amount of CVD in
  death rates in different ethnic groups?
• - In the US increased cardiovascular disease
  deaths in African-American and South-Asian
  populations in comparison with Whites
• - Increased stroke risk in African-American, some
  Hispanic American, Chinese, and Japanese
  populations
• - Migration Ni-Hon-San Study Japanese living in
  Japan had the lowest rates of CHD and cholesterol
  levels, those living in Hawaii had intermediate
  rates for both, those living in San Francisco had
  the highest rates for both

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Descriptive Epidemiology V.
TIME and PLACE

• Question What is the relative amount of CVD in
  different geographical places? What are the time
  trends? International and regional
  characteristics of distribution
• SDR Standardized Death Rate
• Direct mode of standardization, using the age
  distribution of a hypothetical European standard
  population
• Premature death rates for comparison purposes
  (lt64 years of age)

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Descriptive Epidemiology VI. World Trends

• Developed countries decreasing tendencies
  (e.g, USA 30 between 1988-98,
  Sweden 42)
• - improvement of lifestyle factors, for example,
  a decrease of smoking and a higher level of
  health consciousness in many developed countries
• - better diagnostic and therapeutic procedures
  (e.g., bypass surgeries,
  hypertension screening, pharmacological treatment
  of hypertension and hypercholesterinaemia, access
  to health care)
• Developing countries increasing tendencies
• - increasing longevity, urbanization, and western
  type lifestyle

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Descriptive Epidemiology VII. International
Comparisons

• Aims
• a., Where are the rates higher or lower?
• b., Interpretation of time trends
• c., Inequalities in cardiovascular death

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Cardiovascular deaths in Europe (SDR, 2000)

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SDR, diseases of circulatory system in Western
Europe, 0-64 yrs, per 1000000
Austria
    
Denmark
    
Finland
    
France
    
Greece
    
Italy
    
Netherlands
    
Spain
    
    
Switzerland
    
United Kingdom
    
EU-15 average
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SDR, diseases of circulatory system in Eastern
Europe, 0-64 yrs, per 1000000
Croatia
          
Hungary
          
          
          
          
          
          
          
Romania
          
Russian Federation
          
Slovakia
EU-15 average (MSs prior 1.5.2004)
          
          
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SDR, diseases of circulatory system in Hungary,
0-64 yrs, per 1000000
     Finland
     Hungary
     EU-15 average
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Analytic Epidemiology I. Role of Risk Factors

• Over 300 risk factors have been associated with
  coronary heart disease, hypertension and stroke
• Approx. 75 of CVD can be attributed to
  conventional risk factors
• Risk factors of great public health significance
• - high prevalence in many populations
• - great independent impact on CVD risk
• - their control and treatment result in reduced
  CVD risk
• Developing countries double burden of risks
  (problems of undernutrition and infections CVD
  risks)

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Analytic Epidemiology II. Classification 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)
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Analytic Epidemiology III. Hypertension

• - Systolic blood pressure gt140 Hgmm and/or a
  diastolic blood pressure gt 90 Hgmm
• - Free of clinical symptoms for many years
  (screening)
• - In most countries, up to 30 percent of adults
  suffering, increasing with age in civilized
  countries
• - Positive family history
• - Dietary habits (a high intake of salt,
  processed food, low levels of water hardness,
  high thyramine content of food, alcohol use)
• - Modern lifestyle (increased sympathetic
  activity, psychosocial stress, leading position
  in job)

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Analytic Epidemiology IV. Rheumatic Fever and
Rheumatic Heart Disease

• Development Rheumatic fever usually follows an
  untreated beta-haemolytic streptococcal throat
  infection in children
• As a consequence, the heart valves are
  permanently damaged which may progress to heart
  failure
• Today mostly affects children in developing
  countries, linked to poverty, inadequacy of
  health care access
• Occurrence 12 million people currently affected
  by rheumatic fever and RHD, two-thirds are
  children (5-15 years), for example approx. 1 000
  000 in Sub-Saharan Africa, 700 000 in
  South-Central Asia, 176 000 in China, 150 000 in
  North Africa, 40 000 in Eastern Europe (!)

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Analytic Epidemiology V. Abnormal
Blood Lipids

• - Se cholesterol structure and functioning of
  blood vessels, atherosclerotic plaques
• - Altering functions of cholesterol fractions
  (LDL risk, HDL protection)
• - Estrogen tends to raise HDL-cholesterol and
  lower LDL-cholesterol, protection for women in
  reproductive age
• - Partially genetic determination of metabolism,
  partially dependent of nutrition (egg, meats,
  dairy products)

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Current Recommended Lipid Levels
European guidelines US guidelines
Total cholesterol lt5.0 mmol/l lt240 mg/dl (6.2 mmol/l)
LDL-cholesterol lt3.0 mmol/l lt160 mg/dl (3.8 mmol/l)
HDL-cholesterol gt1.0 mmol/l (men) gt1.2 mmol/l (women) gt40 mg/dl (1 mmol/l)
Triglycerides (fasting) lt1.7 mmol/l lt200 mg/dl (2.3 mmol/l)
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Analytic Epidemiology VI. Tobacco Use

• - The link between smoking and CVD (mainly CHD)
  was identified in 1940
• - Greatest risk initiation lt 16 years
• - Passive smoking additional risk
• - Women smokers are at higher risk of CHD and
  CVD than male smokers
• - Several mechanisms damages the endothelium
  lining, increases atherosclerotic plaques, raises
  LDL and lowers HDL, promotes artery spasms,
  raises oxigen demand of the heart muscle
• - Nicotine accelerates the heart rate (RR), and
  raises blood pressure

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Analytic Epidemiology VII. Physical
Inactivity

• - Regular physical activity protective factor
• - Intensity and duration (150 minutes/week
  intermediate or 60 minutes/week heavy)
• - Modernization, urbanization, mechanized
  transport sedentary lifestyle (60 of global
  population)
• - Raises CVD risk and also the development of
  other risk factors (glucose metabolism, diabetes
  mellitus, blood coagulation, obesity, high blood
  pressure, worsening lipid profile)
• - Physical activity helps reduce stress, anxiety
  and depression

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Analytic Epidemiology VIII. Obesity, Diabetes
Mellitus, Unhealthy Diet

• - Body Mass Index gt 25 overweight, gt 30
  obesity
• - A modern epidemic More than 60 of adults in
  the US are overweight or obese, in China 70
  million overweight people
• - Elevates the risk of both CVD and diabetes
  mellitus
• - Diabetes mellitus damages both peripheral and
  coronary blood vessels
• -Unhealthy diet low fruit and vegetable, fiber
  content, and high saturated fat intake, refined
  sugar

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Analytic Epidemiology IX. Psychological and
social factors

• - Psychological factors (Type A behavior,
  hostility)
• - Depression and CVD bidirectional link
• a., depression may increase the risk of CVD and
  worsen recovery process
• b., CVD may induce depression
• - Low socioeconomic status (SES)
• a., in developed countries less educated and
  lower SES groups (accumulation of risk factors)
• b., in developing countries more educated and
  higher SES groups (western lifestyle)

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Cardiovascular Prevention I.

• Primordial Social, legal and other (often
  nonmedical) activities which may lead to a
  lowering of risk factors (e.g., socioeconomic
  development, smoke-free restaurants)
• Primary Controlling risk factors contributing to
  CVD (health education programs, anti-smoking
  campaign, sports programs, nutrition counselling,
  regular check of blood pressure and certain blood
  parameters, e.g., cholesterol, blood lipids,
  glucose)
• Secondary Screening and treatment of symptomatic
  patients, set up personal risk profile
• Tertiary Cardiovascular rehabilitation,
  prevention of recurrence of CVD (new heart
  attack 5-7 times higher risk among CVD patients)

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Cardiovascular Prevention II.

• The individual approach (detecting those at
  greatest risk) lifestyle guidelines (e.g.,
  smoking cessation)
• The population-wide approach (the whole
  population, western lifestyle )
• Example for community-wide CV prevention
  programs
• - Framingham Heart Study (1948-) Framingham Risk
  Scoring
• - North-Karelia Project (1972-) Finland
• - Stanford Projects (1972-75, 1980-86) USA
• - Minnesota Cardiovascular Health Program
  (1980-88) USA
• - Multiple Risk factor Intervention Trial
  (1972-79) USA

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Review Questions (Developed by the Supercourse
team)

• What may be the reasons for the declining CVD
  incidence rates?
• At the same time that there has been an
  epidemic of obesity, the rates of CVD has
  markedly declined. Why hasnt CVD go up in the
  population as obesity has skyrocketed?
• Define the steps to prevent CHD