PREVALENCE OF CORONARY-ARTERY DISEASE AND CORONARY RISK-FACTORS IN THE ELDERLY RURAL ARID URBAN POPULATIONS OF NORTH-INDIA - THE INDIAN LIFE-STYLE AND HEART-STUDY IN THE ELDERLY

Objectives To compare the prevalence rates of coronary artery disease (CAD) and coronary risk factors in the rural and urban populations of north India. Design and setting A cross-sectional survey of two random ly selected villages from Moradabad district and 20 randomly selected streets in the city of Moradabad. Subjects and methods There were 515 rural (280 men and 235 women) and 595 urban (314 men and 281 women) su bjects aged 50-84 years. The survey methods were dietary diaries for 7 -day food-intake records, blood pressure and anthropometric measuremen ts and electrocardiography. Results The total prevalence of CAD on the basis of the clinical histories and electrocardiograms of the subject s was significantly higher among the urban population than it was amon g rural subjects aged 50-84 years (12.1 versus 4.0%) and aged 65-84 ye ars (16.8 Versus 5.4%). The rates were comparable in the two sexes but increased with age. In comparison with rural subjects, urban subjects also had two- to threefold higher prevalences of hypertension, diabet es mellitus, hypercholesterolaemia, hypertriglyceridaemia and central obesity. Risk factor levels were also significantly higher among urban compared with rural subjects but the prevalence of smoking was compar able for both sexes. These differences in risk factors and CAD prevale nce were associated with threefold better economic status and higher i ntakes of total and saturated fat, cholesterol and refined carbohydrat es in urban compared with rural subjects. Risk factors for healthy sub jects were modest or absent. There was nb interaction by urbanrural st atus in the association of the coronary risk with CAD, therefore assoc iation was examined after the data of the two groups had been pooled. Logistic regression analysis after adjustment for age showed that hype rtension was strongly associated with CAD (odds ratio for men 0.91, fo r women 0.62; P < 0.01), hypercholesterolaemia (men 0.81, women 0.88; P < 0.05), saturated fat intake (men 0.74, women 0.72), physical activ ity (men 0.57, women 0.25, P < 0.05), central. obesity (men 0.92, P < 0.05) and smoking (men 0.76, P < 0.05) were also associated with CAD. Conclusions Coronary risk factors and CAD were two- to threefold highe r among the urban compared with the rural population. Hypertension, hy percholesterolaemia saturated fat intake and physical activity were si gnificant risk factors for CAD both in rural and in urban subjects of both sexes.