Postmenopausal use of estrogen and occlusion of coronary arteries.

The degree of coronary artery occlusion was compared between users and nonusers of postmenopausal estrogen among 933 female patients undergoing angiography between the ages 50 and 75 years in the Milwaukee Cardiovascular Data Registry. Users (n = 154) had less occlusion than nonusers (n = 779), and a significant increase in occlusion scores with age was evident for nonusers (p less than 0.001) but not for users (p = 0.50). The age-adjusted odds ratios for use of postmenopausal estrogen among women with moderate and severe levels of occlusion of the coronary arteries were 0.59 (95% confidence interval, 0.48 to 0.73) and 0.37 (95% confidence interval, 0.29 to 0.46), respectively, which indicated a statistically significant, apparent protective effect of postmenopausal estrogen on coronary occlusion. This effect was independent of the type of menopause or other risk factors but not independent of high-density lipoprotein-cholesterol levels. Higher high-density lipoprotein-cholesterol levels among users may indicate a biologic mechanism by which postmenopausal estrogen use lowers the risk of coronary occlusion.