Replacement estrogen use and body mass index.

Peripheral fat is a major source of endogenous estrogens in menopausal women. To investigate whether obesity affects use of replacement estrogens in postmenopausal women, we examined the relation between body mass index and use of replacement estrogens in data from Group Health Cooperative of Puget Sound, the German Cardiovascular Prevention Study, and the Cancer and Steroid Hormone (CASH) study. In each data set, there was a major decline in replacement estrogen use with higher body mass index. All data sets showed hysterectomy to be a strong predictor of replacement estrogen use. Smoking, past use of oral contraceptives and other estrogens, and ages at menarche and menopause did not appear to influence the body mass-estrogen relation. The strong and consistent association between body mass index and use of replacement estrogens in data collected at different times and in different places by different methodologies strongly suggests a common underlying biologic mechanism.