Prevalence of coronary heart disease in the rural population of Thiruvananthapuram district, Kerala, India

To establish the prevalence, with 95% confidence limits, of some of the indicators of coronary heart disease in the rural population of Thiruvananthapuram district, Kerala state, India, we did a field survey on a cluster sample with probability proportionate to size (PPS sample) of 500 households from five villages. Altogether the sample consisted of 1253 individuals who were more than 25 years of age, of which 1130 responded (90%). The survey instruments included the Malayalam translation of the Rose questionnaire, a standard 12-lead electrocardiogram with a battery operated portable electrocardiograph machine, blood pressure measurements using a mercury sphygmomanometer, and routine anthropometric measurements. The prevalence rates estimated were: (a) ECG changes suggestive of coronary heart disease, 36 1000 (95% C.L., 18, 55), (b) Rose questionnaire angina, 48 1000 (95% C.L. 35, 62), (c) definitive evidence of coronary heart disease, 14 1000 (95% C.L., 7, 21), (d) possible evidence of coronary heart disease, 74 1000 (95% C.L., 55, 93). Prevalence of major risk factors were, (a) hypertension by the WHO criteria, 179 1000 (95% C.L., 137, 221), (b) smoking, 219 1000 (95% C.L., 151, 287), (c) diabetes, 40 1000 (95% C.L., 17,63), (d) obesity, 55 1000 (95% C.L., 6, 104). We have found that objective criteria indicate a lower prevalence of coronary heart disease in rural Thiruvananthapuram district when compared to studies from urban centres in India, but the prevalence of angina by Rose questionnaire is greater.