Clustering of cardiovascular risk factors in urban Asian Indians

OBJECTIVE - To study the prevalence of cardiovascular risk factors in native urban Asian Indians and to look for the occurrence of clustering of these factors. RESEARCH DESIGN AND METHODS - The study included 953 subjects (532 men and 421 women), aged greater than or equal to 40 years, selected from a population survey for diabetes, which was conducted in 1994 in Madras, Tamil Nadu, India. Measurements of anthropometry, blood pressure, plasma lipid profile, glucose tolerance, plasma insulin response, and electrocardiogram were made. Based on the normal ranges derived from the population study, abnormalities in anthropometric values, plasma lipids, and insulin values were determined. Age-adjusted prevalences of the abnormalities were calculated using data from a 1991 urban census in Madras. The expected prevalences of the abnormalities in isolation and in combinations were calculated and compared with the corresponding observed figures. RESULTS - The prevalences of risk factors were in the order of central adiposity > dyslipidemia > hyperinsulinemia (2-h) > glucose intolerance > obesity > hypertension. The age-adjusted prevalence of coronary heart disease (CHD) was 3.9% (3.5% in men and 4.5% in women, NS), and T wave inversion was seen in an additional 10.3%. Isolated prevalences of all factors, except hypertension, were in lower frequency than expected. Combinations of each risk factor with one or two more risk factors occurred more frequently (1.3-4 times) than expected by chance. Impaired glucose tolerance and dyslipidemia showed association with hyperinsulinemia, whereas hypertension did not show such an association. CONCLUSIONS - Clustering of the cardiovascular risk factors or the components of insulin resistance syndrome occurs in the native Asian Indian population. This finding underscores the need for preventive aspects of metabolic disorders and CHD.