title: Associations of hormone replacement therapy with bone structure and physical performance among postmenopausal women.
abstract: The purpose of this cohort study was to focus on factors associated with bone mass and structure of lower limbs and physical performance after menopause. Eighty nonsmoking women with a mean age of 62.1 (SD 0.8) years participated in the study. They were classified into two groups by their use of hormone replacement therapy (HRT), either the current users (n = 43) or the never or discontinued users (n = 37). The tibial shaft and distal tibia were scanned with peripheral computed tomography. For the shaft region, the bone mineral content (BMC, g), cortical density (CoD, g/cm(3)), cortical area (CoA, mm(2)), and section modulus (BSI, mm(3)) were determined. For the distal part, the evaluated variables were BMC, total area (ToA), ratio of cortical to total area (CoA/ToA), trabecular density (TrD, g/mm(3)), cortical thickness, BSI, and buckling ratio. Isometric and dynamic muscle strength of the leg extensors, agility and postural sway, and cardiorespiratory capacity (VO(2max)) were measured. Unadjusted values for all bone variables were slightly higher among the HRT users compared to nonusers, with the exception of TrD with no difference. After controlling for body weight, the mean differences (95% confidence interval) remained significant for CoD of the tibial shaft and BSI of the distal tibia, the mean between-group differences being 1.5% (0.4 to 2.5%) and 23.0% (7.1 to 41.3%), respectively. Underlying the greater bending strength, HRT users had thicker cortices and a greater ratio of CoA/ToA. No differences existed between the two study groups for lower limb isometric or dynamic power, cardiorespiratory capacity, or postural balance or sway. HRT may offer protection against bone loss and maintain bone strength, although its ability to improve physical performance is not evident.
authors.affiliation: UKK Institute for Health Promotion Research, FIN-33501 Tampere, Finland. kirsti.uusi-rasi@uta.fi
authors.forename: K
authors.initials: K
authors.lastname: Uusi-Rasi
authors.forename: T J
authors.initials: TJ
authors.lastname: Beck
authors.forename: H
authors.initials: H
authors.lastname: Sievänen
authors.forename: A
authors.initials: A
authors.lastname: Heinonen
authors.forename: I
authors.initials: I
authors.lastname: Vuori
mesh_terms: D015519:Bone Density / Q000187:drug effects* / Q000502:physiology; D016001:Confidence Intervals; D003430:Cross-Sectional Studies; D015914:Estrogen Replacement Therapy / Q000379:methods*; D005080:Exercise Test / Q000187:drug effects* / Q000379:methods; D005260:Female; D006801:Humans; D008875:Middle Aged; D015663:Osteoporosis, Postmenopausal / Q000517:prevention & control*; D017698:Postmenopause / Q000187:drug effects / Q000502:physiology; D012044:Regression Analysis