Objective: The purpose of the study was to compare the body mass and fat compositions of menopausal women who were taking conventional doses of hormone replacement therapy (HRT) with that of menopausal women who were not taking any hormones.
Design: The body fat composition of 169 healthy postmenopausal women was measured using a noninvasive handheld machine, the Electrolipograph (BioAnalogics ELG, Beaverton, OR, USA). Impedance to electrical flow in tissues is lower with increasing water content of the tissue. Information on HRT, lifestyle, diet, smoking, and alcohol was obtained from the medical record and by a telephone interview before women were invited to participate. HRT and non-HRT groups were compared. Multivariate linear regression, which included age, years since menopause, type of menopause, and use of HRT, was performed for each of the two major outcomes: body mass index (BMI) and percentage of body fat.
Results: Comparisons between subgroups showed a large number of significant differences reflecting differences in age since menopause, baseline BMIs, and baseline waist to hip ratios. In the regression model, however, the only factor significantly associated with lower fat and BMI was the use of HRT. Women who were taking HRT had significantly lower percentages of body fat (-4.8%; p < 0.001) and BMI (-2.6 kg/m2; p < 0.001) compared with nonusers. Age and duration and type of menopause were not significant predictors of weight and BMI in this group of postmenopausal women.
Conclusions: In this study, HRT seems to be associated with a significant reduction in postmenopausal weight and fat mass gains. This may be an important mechanism by which HRT exerts its beneficial long-term effects on cardiovascular health.