The rarity of coronary heart disease in South African blacks.

Coronary heart disease (CHD) remains an uncommon disorder in the South African Black population. It has been suggested that herein lies an enigma, since it is believed that these people are considerably exposed to the conventional risk factors for CHD. To test this belief I have assessed the exposure of Black people, in time and degree, to the following CHD risk factors: affluence, age, hypertension, hyperlipidaemia, dietary excess, smoking, physical inactivity, diabetes, obesity, hyperuricaemia and hyperinsulinism. Among males only hypertension, and among females only hypertension and obesity, emerged as prominent factors. However, neither of these is significantly atherogenic in the social, nutritional and metabolic milieu in which Blacks generally live, and obesity is a doubtful atherogenic factor, even in westernized populations. It is therefore concluded that the rarity of CHD in Blacks is not enigmatic, but is appropriate to their environmental circumstances.