We agree with Dr Verdy that the lower weight observed in postmenopausal women taking estrogens is of great interest. However, we doubt that postmenopausal estrogen use causes weight loss, because this effect has not been shown in clinical studies, as he notes in his letter. It seems more probable that postmenopausal estrogen use either is prompted in search of improved health and appearance by women who are already weight conscious for the same reasons, or that postmenopausal estrogen use is initiated selectively by lean women because they have more postmenopausal symptoms. The latter hypothesis is attractive, because circulating estrogen in postmenopausal women is produced from plasma androgens, and the extent of conversion is positively correlated with body weight.1 More sustained plasma estrogen levels in obese postmenopausal women might be expected to reduce the frequency of hot flushes and consequently to reduce the frequency of replacement estrogen use.
Barrett-Connor E. Postmenopausal Hormone Users and Obesity-Reply. JAMA. 1980;243(19):1896–1897. doi:10.1001/jama.1980.03300450012008