Plasma sex hormones and ischemic heart disease.

The reason why men have a higher incidence of ischemic heart disease than women, and women rarely develop ischemic heart disease before the menopause, is not known. However, elevated plasma estradiol and estrone concentrations have been found in men surviving myocardial infarction. Hence, hyperestrogenemia has been suggested as a coronary risk factor. To assess this theory we review the literature on sex steroid production, the relationship between established coronary risk factors and plasma sex hormones, as well as results from clinical trials in which estrogens have been administered to men and women. Other possible explanations why plasma estradiol levels are elevated in male survivors of myocardial infarction are discussed. Based on earlier and recent evidence, it is hypothesized that the elevated plasma estradiol concentration found in men surviving myocardial infarction is due to either the myocardial infarction itself or established risk factors such as smoking or hypertension.