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 females (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 hyperuricaemia (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 personal history of ischaemic heart disease was 13.7%. The high-density lipoprotein (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 attended a dental clinic, the prevalence of selected risk factors were: hypertension 13% (M, 12.6%; F, 13.6%), overweight 40% (M, 16.8%; F, 65%), hypercholesterolaemia 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 smoking 16.2% (M, 28.1%; F, 3.4%). The total percentage of subjects with abnormal ECG was 40%, and that of abnormal ECGs in those with a family history of ischaemic heart disease was 1.1%. The ratio of HDL/total cholesterol was 81.3% (M, 76.7%, F, 83.1%). The combination of diabetes mellitus, hyperlipidaemia and hypertension appears to play an important role in the aetiology of ischaemic heart disease in Indians. In contrast, the low incidence of this disease in Black people is probably due to the lower prevalence of hyperlipidaemia and diabetes mellitus.(2,3)