Family history as a risk factor of coronary heart disease in patients under 60 years of age.

The role of family history as a risk factor of coronary heart disease was explored in the first-degree relatives of 121 female and 586 male survivors of a recent acute myocardial infarction and in those of 130 control women. It was significantly more common for female patients than male patients to have first-degree relatives with coronary artery disease before the age of 65 (76% vs 62%, P = 0.0026). For the sisters of the female patients the cumulative risk of coronary heart disease by the age of 65 years was almost twice that of the sisters of the male patients (25.9% vs 15.8%, P = 0.0123). The risk for the brothers of the females did not significantly differ from that of the brothers of the male patients, but it was 3.5 times that of the brothers of the controls. Thus, while a history of coronary heart disease in first-degree relatives is a risk factor for the disease, the risk is greater in women than in men.