Regional variations in cardiovascular risk factors in India: India heart watch

Cardiovascular disease (CVD) is an important cause of mortality and morbidity in India. Mortality statistics and morbidity surveys indicate substantial regional variations in CVD prevalence and mortality rates. Data from the Registrar General of India reported greater age-adjusted cardiovascular mortality in southern and eastern states of the country. Coronary heart disease (CHD) mortality is greater in south India while stroke is more common in the eastern Indian states. CHD prevalence is higher in urban Indian populations while stroke mortality is similar in urban and rural regions. Case-control studies in India have identified that the common major risk factors account for more than 90% of incident myocardial infarctions and stroke. The case-control INTERHEART and INTERSTROKE studies reported that hypertension, lipid abnormalities, smoking, obesity, diabetes, sedentary lifestyle, low fruit and vegetable intake, and psychosocial stress are as important in India as in other populations of the world. Individual studies have reported that there are substantial regional variations in risk factors in India. At a macro-level these regional variations in risk factors explain some of the regional differences in CVD mortality. However, there is need to study the prevalence of multiple cardiovascular risk factors in different regions of India and to correlate them with variations in CVD mortality using a uniform protocol. There is also a need to determine the "causes of the causes" or fundamental determinants of these risk factors. The India Heart Watch study has been designed to study socioeconomic, anthropometric and biochemical risk factors in urban populations in different regions of the country in order to identify regional differences.