Lean mass as a determinant of bone mineral density of proximal femur in postmenopausal women

ABSTRACT Objective: To verify which component of body composition (BC) has greater influence on postmenopausal women bone mineral density (BMD). Subjects and methods: Four hundred and thirty women undergoing treatment for osteoporosis and 513 untreated women, except for calcium and vitamin D. Multiple linear regression analysis was performed in order to correlated BMD at lumbar spine (LS), total femur (FT), femoral neck (FN) with body mass (BM), total lean mass (LM) and total fat mass (FM), all determined by DXA. Results: BM significantly correlated with all bone sites in untreated and treated women (r = 0.420 vs 0.277 at LS; r = 0.490 vs 0.418 at FN, r = 0.496 vs 0.414 at FT, respectively). In untreated women, the LM correlated better than FM with all sites, explaining 179% of LS; 32.3% of FN and 30.2% of FT; whereas FM explained 13.2% of LS; 277% of FN, 23.4% of FT In treated women, correlations with BC were less relevant, with the LM explaining 6.7% of BMD at LS; 15.2% of FN, 16% of FT, whereas the FM explained 8.1% of LS; 179% of FN and 176% of FT. Conclusion: LM in untreated women was better predictor of BMD than FM, especialy for distal femur, where it explained more than 30% of the BMD, suggesting that maintaining a healthy muscle mass may contribute to decrease osteoporosis risk. Treatment with anti-osteoporotic drugs seems to mask these relationships. Arch Endocrinol Metab. 2018;62(4):431-7

摘要
目的：验证身体成分（body composition, BC）的哪一项组分对绝经后女性的骨密度（bone mineral density, BMD）影响更大。
研究对象与方法：纳入430例接受骨质疏松治疗的女性，以及513名仅补充钙与维生素D、未接受其他抗骨质疏松治疗的女性。采用双能X线吸收法（DXA）测定体质量（body mass, BM）、全身去脂体重（total lean mass, LM）及全身体脂质量（total fat mass, FM），通过多元线性回归分析，探讨腰椎（lumbar spine, LS）、股骨总区域（total femur, FT）及股骨颈（femoral neck, FN）的骨密度与上述身体成分指标的相关性。
结果：体质量与未治疗组及治疗组女性的所有骨监测位点均显著相关（腰椎部位r值分别为0.420与0.277；股骨颈部位r值分别为0.490与0.418；股骨总区域部位r值分别为0.496与0.414）。在未治疗组中，去脂体重与各骨位点的相关性优于体脂质量：去脂体重可分别解释腰椎、股骨颈及股骨总区域骨密度变异的179%、32.3%及30.2%；而体脂质量仅可分别解释上述位点的13.2%、277%及23.4%。在治疗组中，身体成分与骨密度的相关性相对较弱：去脂体重可分别解释腰椎、股骨颈及股骨总区域骨密度变异的6.7%、15.2%及16%；体脂质量则可分别解释上述位点的8.1%、179%及176%。
结论：未接受治疗的绝经后女性中，去脂体重对骨密度的预测效果优于体脂质量，尤其在股骨远端部位，其可解释超过30%的骨密度变异，提示维持健康的肌肉量可降低骨质疏松风险。抗骨质疏松药物治疗似乎会掩盖上述身体成分与骨密度的关联关系。
《内分泌代谢档案》（Arch Endocrinol Metab）2018年；62(4):431-7