Prevalence of familial hypercholesterolaemia in three rural South African communities.

The prevalence of familial hypercholesterolaemia (FH) was estimated in three predominantly Afrikaner communities in the south-western Cape. Young hypercholesterolaemics (N = 136) identified during the Coronary Risk Factor Study (CORIS) and their first-degree relatives were invited to attend a follow-up study of their blood lipids (total and high-density lipoprotein cholesterol and triglyceride values) 6 months after the CORIS baseline study. Of the 62 index cases who fulfilled the qualifying conditions, 7 were classified as suffering from FH. This ratio of 7 FH cases out of 62 index cases represents a prevalence of 1:87 in the study population, which is considerably higher than the 1:500 found elsewhere in the world. For several reasons 1:87 may be seen as an underestimate. The mean serum cholesterol level in the 7 FH cases was 10.08 mmol/l. Fasting triglyceride values indicated that type IIa was the most frequent hyperlipoproteinaemia. The mean percentage of high-density lipoprotein: total cholesterol in the 7 FH cases was also considerably below either the same age group in the CORIS population or the index cases not classified as FH.