RISK-FACTORS LEADING TO CORONARY HEART-DISEASE AMONG THE BLACK, INDIAN AND WHITE PEOPLES OF DURBAN

In a random house-to-house study of 778 Indian (408 males (M), 370 fem ales (F)) in Durban, we found 15.3% with a history of ischaemic heart disease and 41.3% with a family history of ischaemic heart disease.(1) The prevalence of selected risk factors was 18.6% for hypertension (M , 17.4%; F, 17.7%), 15.8% for diabetes mellitus (M, 15.3%; F, 16.2%), 24.7% for smoking less than or equal to 10 cigarettes per day (M, 41.9 %; F, 5.7%), 12.4% for overweight as defined by the body mass index (M , 3.2%; F, 21.6%), 20.1% for hypercholesterolaemia, (M, 22.3%; F, 20.0 %), for hypertriglyceridaemia (M, 24.6%; F, 16.1%) and 25.9% for hyper uricaemia (M, 10.4%; F, 15.5%). The overall percentage of abnormal ECG was 48%, while that of abnormal ECG in subjects with a family or pers onal history of ischaemic heart disease was 13.7%. The high-density li poprotein (HDL), total cholesterol ratio was 22.6% (M, 22.1%; F, 23.1% ). In contrast, among 368 Black subjects (191 M and 177 F) who attende d a dental clinic, the prevalence of selected risk factors were: hyper tension 13% (M, 12.6%; F, 13.6%), overweight 40% (M, 16.8%; F, 65%), h ypercholesterolaemia 5% (M, 5.4%; F, 4.7%), hypertriglyceridaemia 7.5% (M, 11.2%; F, 3.5%), hyperuricaemia 6.1% (M, 4.3%; F, 8.1%) and smoki ng 16.2% (M, 28.1%; F, 3.4%). The total percentage of subjects with ab normal ECG was 40%, and that of abnormal ECGs in those with a family h istory of ischaemic heart disease was 1.1%. The ratio of HDL/total cho lesterol was 81.3% (M, 76.7%, F, 83.1%). The combination of diabetes m ellitus, hyperlipidaemia and hypertension appears to play an important role in the aetiology of ischaemic heart disease in Indians. In contr ast, the low incidence of this disease in Black people is probably due to the lower prevalence of hyperlipidaemia and diabetes mellitus.(2,3 )