Family history—and independent risk factors for coronary heart disease, it is time to be practical

Epidemiological studies indicate that family or parental history of myocardial infarction is a risk factor for coronary heart disease (CHD). The innate susceptibility to CHD was suggested 20 years ago in the Framingham cohort, which showed that family history of premature CHD conferred excess risk. A history of death due to CHD in parents of the cohort was found to be associated with a 30% increased risk of CHD, a risk which was not mediated by other risk factors. The common disorders such as CHD, diabetes, Alzheimer’s disease or bronchial asthma are considered complex diseases arising from interactions between genes and environment. The usual measure of the effect of gene–environment interaction is the ratio of disease incidence between exposed and unexposed individuals i.e. individuals with a positive or negative family history of disease. But very important questions remain: how to define a positive family history? Usually, how far both parents and siblings are affected is considered together, and the age limit at which they were affected is given. It is well known that females are prone to CHD at least 10 years later than men. A positive family history is seen as fathers who succumb earlier than 55 years of age, and mothers before 65 years. The answers always depend on the level of information available, and the intellectual power of the probands. Those with higher education may be considered better informed in this matter. The maternal and paternal history of myocardial infarction (MI) and risk of cardiovascular disease in men and women was recently studied in the Physician’s Health Study and the Women’s Health Study. Compared with men with a negative family history, of those affected either only maternal or paternal, or both maternal and paternal conferred for first-degree relatives the relative risk (RR) of 1·71, 1·40 and 1·85. Among women, the RR was, respectively, 1·4, 1·15 and 2·05. It means, that women with both parents affected are at particularly high risk.