The impending global epidemic of cardiovascular diseases.

During the past 30 years, large declines in cardiovascular disease death rates have been experienced in several western countries, whereas substantial increases have been experienced in developing countries. These contrasting trends are expected to continue. Over the next three decades, premature morbidity and mortality attributable to cardiovascular disease will almost double globally from 85 million disability adjusted life years in 1990, to 140– 160 million DALY in 2020, with about 80% of this burden occurring in developing countries. Other than subSaharan Africa, all geographic regions are experiencing a substantial disease burden from ischaemic heart disease (Table 1) and have experienced substantial increases in mortality rates over the last decade (Table 2). The increases in cardiovascular disease in developing countries are probably a result of at least three contributing factors: first, decreasing mortality from acute infectious diseases and increases in life expectancy result in a higher proportion of individuals reaching middle and old age. Second, lifestyle and socioeconomic changes associated with urbanization in developing nations lead to higher levels of risk factors for cardiovascular disease. Third, special susceptibility of certain populations (e.g. due to specific genes) may lead to a greater impact on clinical events compared to western populations (Fig. 1). The rates projected in Tables 1 and 2 are based solely upon demographic changes. If the prevalence of various cardiovascular disease risk factors also rise as a consequence of adverse lifestyle changes accompanying industrialization and urbanization, the rates of cardiovascular disease mortality and morbidity could rise even higher than the projected rates. Further, both the degree and the duration of exposure to the cardiovascular disease risk factors would increase as a result of higher risk factor levels coupled with a longer life expectancy. Higher prevalence of both risk factors for cardiovascular disease and disease rates in urban compared to rural communities in India and China provide evidence of these trends. Lifestyle changes observed in countries undergoing transition include changes in diet, physical activity and tobacco use. The globalization of food production and marketing has resulted in greatly increased availability of cheap vegetable oils and fats, and increased consumption of energy-dense foods which may be poor in dietary fibre and several micronutrients. Other characteristics of this nutrition transition include a shift from plant to animal protein, and shifts towards refined carbohydrates and sweets, and increased prevalence of obesity. This transition now occurs even in countries and groups with a relatively low level of income, and is further accelerated by urbanization. In South Africa for example, length of time living in an urban Table 1 Disability-adjusted life-years lost (in hundreds of thousands) from ischaemic heart disease in 1990 (projected data from the World Bank)