The relationship of body mass index (BMI), conicity index (CI) and waist circumference to four coronary heart disease (CHD) risk factors (systolic and diastolic blood pressures, total cholesterol and high-density lipoprotein (HDL) cholesterol levels) was examined in urban (n = 110) and rural (n = 102) men aged > or = 20 years, drawn from the 'Reddy' population of Southern Andhra Pradesh, India. Using ANCOVA we found significant difference (< 0.01) for systolic blood pressure, total cholesterol and HDL cholesterol between the urban and rural samples. The Pearson's correlation coefficients suggest that BMI and waist circumference had significant relationships with most of the risk factors in both the populations. The CI did not significantly influence any of the risk factors in the urban population; however, in the rural population, CI did show a significant positive relationship with both of the blood pressures and with TC. Even after controlling for age, smoking and physical activity (partial correlations), the relations remained constant. In multiple linear regression, BMI showed significant positive association with systolic and diastolic blood pressures (<0.01) and HDL cholesterol (<0.05) in the rural population only. However, the Cl showed a significant association with HDL cholesterol, and waist circumference with total cholesterol and HDL cholesterol in the rural population. The results of the present study revealed that BMI and waist circumference had a greater influence on the CHD risk factors, and that the influence was more conspicuous in the rural sample. Comparing the association of abdominal obesity measures (CI and waist circumference) with CHD risk factors, waist circumference better correlated with most of the risk factors. Hence the present study suggests that BMI and waist circumference are better indicators of CHD risk factors. However, the importance of Cl has to be further studied in South Asian populations.