Long-term changes in lean mass in postmenopausal women and the effects of osteoporosis pharmacotherapy: A 10-year longitudinal study

OBJECTIVES: Although sarcopenia is diagnosed using appendicular lean mass (ALM), only a few long-term studies on changes in both ALM and bone mineral density (BMD) have been reported. The purposes of this study are to evaluate the changes in the parameters of lean mass and bone mass over a 10-year interval and to estimate the effects of osteoporosis pharmacotherapy on muscle. METHODS: A total of 175 postmenopausal women were evaluated at baseline and after 10 years for BMD, ALM, fat mass, height, and weight. Subjects were further divided into an osteoporosis treatment group (n = 60) and a control group (n = 67) according to whether they had received pharmacotherapy for > 5 years. This was followed by propensity score matching for age, height, weight, and body mass index (BMI), and estimated parameters were compared between groups. RESULTS: Height, weight, ALM, and fat mass decreased significantly over 10 years (P < 0.05). However, lean mass index (LMI), derived as the ALM divided by the height squared, increased significantly (P < 0.001). BMD increased significantly with osteoporosis treatment (P < 0.05), while no significant differences were observed between the osteoporosis treatment and control groups in the changes to ALM or fat mass. CONCLUSIONS: ALM was decreased, while LMI was significantly increased. This contradictory result seems to be affected by age-related height loss. Thus, the effect of height loss needs to be considered when sarcopenia is evaluated longitudinally using LMI.