Relation of family history and reversible risk factors to coronary heart disease prevalence in an Afrikaner community.

In a cross-sectional study of an Afrikaner community (n = 2,722 men and n = 3,173 women aged 25-64 years), family history of coronary heart disease (CHD) was associated with an adverse risk factor profile and with prevalent CHD. Men with myocardial infarction (MI) and a family history of CHD had higher total minus high density lipoprotein cholesterol (TC-HDLC) levels than men with MI but no CHD family history. In preliminary multiple regression analyses, family history of CHD appeared to exert its effect partly independently of known risk factors and partly dependently through age, TC minus HDLC, and HDLC. Even though their association with MI was weakened after entering family history into the models, the reversible risk factors (particularly TC minus HDLC, HDLC, and uric acid levels) continued to contribute to CHD. For MI in men, there was an interaction between family history of CHD and TC minus HDLC, to the extent that raised TC minus HDLC levels were adverse only in the presence of a positive CHD family history. The findings suggest coinheritance of high blood cholesterol and increased susceptibility to CHD. If confirmed in prospective studies, the interaction between family history and TC minus HDLC will have implications for cholesterol screening and management.