Effects of estradiol with and without testosterone on body composition and relationships with lipids in postmenopausal women.

OBJECTIVE The cardioprotective effects of postmenopausal estrogen replacement therapy are mediated by several mechanisms, including favorable effects on lipids and lipoproteins. The extent to which the latter reflects modification of body fat distribution by sex steroids is not known. Hence, we investigated the relationships between changes in lipids and measures of body composition in postmenopausal women who were administered estrogen therapy with and without testosterone. DESIGN We randomized 33 postmenopausal women to treatment with either estradiol 50 mg (E) alone or estradiol 50 mg plus testosterone 50 mg implants (E&T) administered every 3 months for 2 years in conjunction with cyclic oral progestins for women with an intact uterus. RESULTS Both therapies were associated with sustained reductions in total cholesterol and low-density lipoprotein (LDL) cholesterol. In women who received E but not E&T, hip (p < 0.001) and abdominal circumferences (p < 0.05) and fat mass:fat-free mass (FM:FFM) ratio over the abdomen (p < 0.05) declined. E&T but not E resulted in increased FFM (p < 0.001) and a reduced FM:FFM ratio (p < 0.05). For E but not E&T, the decrease in LDL cholesterol was significantly related to changes in total and compartmental body fat and to change in the FM:FFM ratio (p < 0.05). CONCLUSION Estrogen replacement has effects on body fat distribution in postmenopausal women that are associated with improved lipid parameters. Addition ofparenteral testosterone does not negate the favorable effects of estrogen on LDL cholesterol levels but may attenuate the reduction in centralized body fat achieved with E implants.