Health Transition And Emerging Cardiovascular Diseases In Developing Countries

Health Transition And Emerging Cardiovascular Diseases In Developing Countries Dr Sunita Dodani Department of Epidemiology University of Pittsburgh Presentation overview By the end of this lecture we will learn about • Epidemiologic & demographic transition in developing countries • Examples of demographic transition • Double burden of diseases • Causes of Epidemiologic transition • Available CVD data in Pakistan • What can be done to reduce the burden Epidemiologic Transition A characteristic shift in the disease pattern of a population as mortality falls during the demographic transition: acute, infectious diseases are reduced, while chronic, degenerative diseases increase in prominence, causing a gradual shift in the age pattern of mortality from younger to older ages (Omran 1970s) Rising Life Expectancy 80 70 60 50 40 30 20 10 0 1950 1960 1970 1980 1990 WHO report, 1997 (Age in years) World Less Developed More Developed Epidemiologic Transition Past, Present & Future Historical ETs • rise of infectious disease (~8000 B.C) • decline of infectious disease & rise of CVD (19th-20th C) • decline of cardiovascular disease (late 20th C) Reverse ETs • rise of violence (late 20th C) • resurgent infectious disease (late 20th C) Possible future ETs • decline of cancer, dementia, etc. (21st C ?) (WHO,2000) Epidemiologic Transition Demographic transitions: Indicators over time Birth & Death Rate (per 1000) 50 40 30 20 10 0 1800 (UK as an indicator for the „western‟ Model) population(Millions) Population Death Rate Birth Rate Mortality Rate Fertility Rate Birth Rate Size Population Age Population 1840 1880 1920 1960 Omran, Millbank Mem Fund Quart, 1971;49,215 Epidemiologic Transition Models of Demographic transitions Western 50 45 40 35 30 25 20 15 10 5 0 Accelerated 50 45 40 35 30 25 20 15 10 5 0 Delayed (Most LDC) 50 45 40 35 30 25 20 15 10 5 0 UK Japan Sri Lanka 1800 1880 1960 1800 1840 1880 1920 1960 1840 1920 1800 1880 1960 1800 1840 1880 1920 1960 1840 1920 1800 1880 1960 1800 1840 1880 1920 1960 1840 1920 Omran, Millbank Mem Fund Quart, 1971;49,215 Recent declines in Fertility rates in developing countries (United Nations 1993) 1965-70 Thailand China Bangladesh Turkey Mexico Indonesia Brazil Egypt India Philippines Epidemiologic Transition 1985-90 2.3 2.3 3.6 3.0 3.8 3.3 3.5 4.4 4.2 4.7 Prop. Diff 62% 62% 48% 46% 43% 41% 34% 33% 26% 21% 6.1 6.0 6.9 5.6 6.7 5.6 5.3 6.6 5.7 6.0 Pakistan Nigeria 7.0 6.9 7.0 6.9 0% 0% Epidemiologic Transition • Epidemics of NCDs are presently emerging, or accelerating, in most developing countries • CVDs, cancers, diabetes, neuropsychiatric ailments and other chronic diseases are major contributors to the burden of disease • Infections and nutritional deficiencies are receding as leading contributors to death and disability….. Still prevalent Double Burden of Diseases (Murray & Lopez, 1996) Cardiovascular disease transition • • • What is current burden of diseases in Asia? Asia has 50% percent of the total world's burden of disease. countries vary on where they are on the economic development and epidemiologic transition spectrum. Leaving China aside, India and the rest of Asia--a heterogeneous group of 49 countries- about 50% of this burden is from communicable diseases (such as diarrhea) Another 40%from noncommunicable diseases 10 percent is from other causes, such as injuries (Murray & Lopez, 1990) • • Epidemiologic transition Current & Projected Burden of Diseases China 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% 1990 2020 1990 2020 1990 2020 Percent of total burden India Rest of Asia Injuries Non Communicable disease Communicable disease (Murray & Lopez, 1990) Epidemiologic transition • Asia is evenly burdened by both the unfinished agenda of communicable diseases and the growing burden of noncommunicable diseases. • This is different from what we see in the established market economies, driven by noncommunicable diseases, and in subSaharan Africa, driven by communicable diseases. Epidemiologic Transition Global burden of disease(1998): Contribution of low and middle income countries Low income high income plus middle income World Total death Thousands Percentage Non communicable disease (NCDs) Thousands 31,717 countries countries 53,929 8,033 14.9 45,897 85.1 7,024 24,693 Percentage Total disability-adjusted life years (DALYs) lost Thousands Percentage DALY loss due to NCDs Thousands 595,363 22.1 77.9 1,382,564 108,305 7.8 1,274, 259 92.2 87,732 507,631 Percentage 14.7 85.3 Epidemiologic transition Determinants and dynamics of the CVD Epidemic in the developing Countries Health transitions: demographic transitions and epidemiologic transitions Mortality Public Nutrition Industrialization Economic Infant sanitation technology and Urbanization Social & Mortality for health Environmental Housing care health Changes Life care expectancy Per capita Income fertility Wealth Level of RF: fat, calories, tobacco, sedentary habits NCD Infectious diseases Persons at risk of developing NCDs Increasing and aging Population Determinants and dynamics of the CVD Epidemic in the developing Countries • Excess, early, and extensive CHD in persons of South Asian origin • The excess mortality has not been fully explained by the major conventional risk factors. • Diabetes mellitus and impaired glucose tolerance highly prevalent. (Reddy KS, circ 1998). • Central obesity, ↑triglycerides, ↓HDL with or without glucose intolerance, characterize a phenotype. • genetic factors predispose to ↑lipoprotein(a) levels, the central obesity/glucose intolerance/dyslipidemia complex collectively labeled as the “metabolic syndrome” Data from South Asian Immigrant studies Determinants and dynamics of the CVD epidemic in the developing countries Other Possible factors • Relationship between early life characteristics and susceptibility to NCD in adult hood ( Barker‟s hypothesis) (Baker DJP,BMJ,1993) – Low birth weight associated with increased CVD – Poor infant growth and CVD relation • Genetic–environment interactions (Enas EA, Clin. Cardiol. 1995; 18: 131–5) - Amplification of expression of risk to some environmental changes esp. South Asian population) - Thrifty gene (e.g. in South Asians) CVD epidemic in developing & developed countries. Are they same? The determinants of health transition in the developing countries are similar to those that charted the course of the epidemics in the developed countries but dynamics are different. • The compressed time frame of transition in the developing countries imposes a large, double burden of communicable and non-communicable diseases. • Urbanization in developing countries occurs in settings of high poverty levels and international debt, restricting resources for public health responses. • Prevention began in developed countries when the epidemic had peaked, and often accelerated a secular downswing, while the efforts in the developing countries are commencing when the epidemic is on the upswing. CVD epidemic in developing & developed countries. Are they same? • Urban populations have higher levels of CVD risk factors related to diet and physical activity (overweight, hypertension, dyslipidaemia and diabetes) • Tobacco consumption is more widely prevalent in rural population • The social gradient will reverse as the epidemics mature. • The poor will become progressively vulnerable to the ravages of these diseases and will have little access to the expensive and technology-curative care. • The scarce societal resources to the treatment of these disorders dangerously depletes the resources available for the „unfinished agenda‟ of infectious and nutritional disorders that almost exclusively afflict the poor Burden of CVD in Pakistan Coronary heart disease Mortality statistics • Specific mortality data ideal for making comparisons with other countries are not available • Inadequate and inappropriate death certification, and multiple concurrent causes of death Population surveys • Pitfalls in sampling design, sample size standardization and measurement errors, but still remain the most important source of information today National health Survey of Pakistan (NHSP) • Ischemic Heart Disease (IHD) was reported as 12% of the adult mortality in Pakistan. • Tobacco use: 29% and 3.4 % in adult males and females‟ respectively • Hypertension - estimated 12 million hypertensives in the country of the total 120 million population - Prevalence is 17.9 % of the overall adult population with 16.4% and 21.5% being the rural and urban prevalence. - > 45 years, one in three Pakistanis (33%) are hypertensive - 3% adequately controlled Burden of CVD in Pakistan Burden of CVD in Pakistan • Diabetes - Pakistan is among the top 10 world nations for high numbers of people with diabetes - Prevalence… 10.6% • Obesity (WHO criteria) - 1 in 7urban males adults (>15 years) is obese or overweight with 22% prevalence in males of 25- 44 years. - In females, 37% in 24-44 years and 40% in 45-64 years in urban female population Burden of CVD in Pakistan Temporal Trends • Most of our knowledge about prevention and treatment derives from studies conducted in developed countries and predominantly among white populations • Validated nationally representative estimates of cause specific mortality and morbidity are not available for any country in South Asia • CHD mortality rate of South Asian immigrants compared with other populations remains high. • CVDs are major and growing contributors to mortality and disability in South Asia Prevention of CVD • There is an urgent need to establish appropriate research studies, increase awareness of the CVD burden, and develop preventive strategies. • Prevention and treatment strategies that have been proven to be effective in developed countries should be adapted for developing countries. • Prevention is the best option as an approach to reduce CVD burden. • Do we know enough to prevent this CVD Epidemic in the first place.