Impact of hormone replacement therapy on the body mass and fat compositions of menopausal women: A cross-sectional study

Objective: The purpose of the study was to compare the body mass and fat co mpositions of menopausal women who were taking conventional doses of hormon e replacement therapy (HRT) with that of menopausal women who were not taki ng any hormones. Design: The body fat composition of 169 healthy postmenopausal women was me asured using a noninvasive handheld machine, the Electrolipograph (BioAnalo gics ELG, Beaverton, OR, USA). Impedance to electrical flow in tissues is l ower with increasing water content of the tissue. Information on HRT, lifes tyle, diet, smoking, and alcohol was obtained from the medical record and b y a telephone interview before women were invited to participate. HRT and n on-HRT groups were compared. Multivariate linear regression, which included age, years since menopause, type of menopause, and use of HRT, was perform ed 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 onl y 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/m(2); p < 0.001) compared with nonuser s. Age and duration and type of menopause were not significant predictors o f weight and BMI in this group of postmenopausal women. Conclusions: In this study, HRT seems to be associated with a significant r eduction in postmenopausal weight and fat mass gains. This may be an import ant mechanism by which HRT exerts its beneficial long-term effects on cardi ovascular health. (Menopause 1999;6:312-315. (C) 1999, The North American M enopause Society.).