title: Protection of bone mass by estrogens and raloxifene during exercise-induced weight Loss.
abstract: The aim of this study was to determine whether estrogen and/or raloxifene help to conserve bone mineral density (BMD) during moderate weight loss. Postmenopausal women (n = 68) participated in a 6-month weight loss program that consisted primarily of supervised exercise training. Another 26 women were studied over 6 months of weight stability. All participants were randomized to three treatment arms: placebo, raloxifene (60 mg/d), or hormone therapy (HT; conjugated estrogens, 0.625 mg/d; trimonthly medroxyprogesterone acetate, 5 mg/d for 13 d, for women with a uterus). Changes in body weight (mean +/- se) averaged 0.8 +/- 0.5 kg in the weight-stable group and -4.1 +/- 0.4 kg in the weight loss group. Across all measured skeletal sites, average changes in BMD in weight stable women were -0.6 +/- 1.1% (n = 7), 0.9 +/- 0.6% (n = 9), and 3.0 +/- 0.7% (n = 10) in the placebo, raloxifene, and HT groups, respectively; comparable BMD changes in the weight loss groups were -1.5 +/- 0.5% (n = 22), -0.5 +/- 0.5% (n = 23), and 1.1 +/- 0.4% (n = 23). There were no significant interactions between weight loss and drug treatment on changes in BMD, but there were significant main effects of weight loss on lumbar spine (P = 0.022), total hip (P = 0.010), and trochanter BMD (P < 0.001). These findings suggest that weight loss, even when modest in magnitude and induced by exercise training, causes a reduction in BMD, particularly in women not taking raloxifene or HT. It is not known whether reductions in BMD of this magnitude increase the risk for osteoporotic fracture.
authors.affiliation: Division of Geratric Medicine, Department of Medicine, University of Colorado Health Sciences Center, Denver, Colorado 80262, USA. wendee.gozansky@UCHSC.edu
authors.forename: W S
authors.initials: WS
authors.lastname: Gozansky
authors.forename: R E
authors.initials: RE
authors.lastname: Van Pelt
authors.forename: C M
authors.initials: CM
authors.lastname: Jankowski
authors.forename: R S
authors.initials: RS
authors.lastname: Schwartz
authors.forename: W M
authors.initials: WM
authors.lastname: Kohrt
mesh_terms: D000368:Aged; D001823:Body Composition; D015519:Bone Density / Q000187:drug effects*; D004967:Estrogens / Q000494:pharmacology*; D015444:Exercise; D005260:Female; D006801:Humans; D008875:Middle Aged; D020849:Raloxifene Hydrochloride / Q000494:pharmacology*; D015431:Weight Loss
chemical_list: D004967:Estrogens; D020849:Raloxifene Hydrochloride