Coronary heart disease and risk factors in Black South Africans: a case-control study

Coronary heart disease (CHD) was uncommon in Black people living in Africa before 1970. Since then CHD risk factor levels have increased, while CHD rates have remained low.

This case-control study aims to assess the relationship between CHD and known risk factors in urban Black South Africans.

Eighty-nine cases with CHD and 356 controls attending the Kalafong hospital were recruited between 1982 and 1986 and followed up until 1994. Family and personal medical histories were recorded, along with a clinical examination and special investigations to assess risk factor profiles, clinical presentation and target organ damage. The relationship of the risk factors, target organ damage, and the development of CHD was assessed by using a stepwise multiple logistic regression procedure.

Far more cases than controls had a family and personal medical history and risk factors related to CHD. Those relating to the development of CHD were family history of myocardial infarction (odds ratio [OR] 17.29; 95% confidence interval [CI] 5.48-54.51), hypertension (OR 8.38, 95% CI 3.66-19.17), family history of hypertension (OR 4.33, 95% CI 2.21-8.52), low high-density lipoprotein cholesterol/low-density lipoprotein cholesterol ratio (OR 2.82, 95% CI 1.24-7.22), and type 2 diabetes (OR 2.99, 95% CI 1.19-6.68). Hypercholesterolemia was marginally associated (OR 2.53, 95% CI .92-6.89).

Evidence is provided that an association exists between CHD and the major risk factors for cardiovascular diseases in urban Black South Africans. A relationship between genetic factors and the development of CHD was also identified in this population group.