Bevier W C, Wiswell R A, Pyka G, Kozak K C, Newhall K M, Marcus R
Aging Study Unit, VA Medical Center, Palo Alto, CA 94304.
J Bone Miner Res. 1989 Jun;4(3):421-32. doi: 10.1002/jbmr.5650040318.
We evaluated the relationship of body composition, maximal aerobic capacity (VO2max), and muscle strength to bone mineral density in 91 healthy men and women, age 61-84 years. Lean body mass was estimated from two independent measures of fat mass, bioelectrical impedance and skinfold thickness. VO2max was determined by treadmill ergometry with direct measurement of oxygen consumption. Grip and back strength were measured by isometric dynamometry. Mineral density of lumbar spine and midradius were measured by dual- and single-photon absorptiometry. Men had significantly greater lean mass, muscle strength, aerobic capacity, and bone density than women. In women, grip strength correlated with forearm and spine density (r = 0.37, r = 0.28, p less than 0.05). In men, grip strength correlated with forearm density (r = 0.47, p less than 0.05), and back strength was significantly correlated with both spine (r = 0.46, p less than 0.01) and forearm density (r = 0.46, p less than 0.01). In women, neither forearm nor spine density correlated significantly with aerobic capacity. In men, midradius density did not correlate significantly with oxygen consumption, but the simple correlation between spine density and VO2max was significant (r = 0.41, p less than 0.05). Back strength and VO2max were significantly related in men (r = 0.47, p less than 0.01). By stepwise multiple regression, back strength emerged as the most robust predictor of spine mineral, accounting for 19% of the variation in bone density. Addition of VO2max to the regression did not add significant predictive value. However, when VO2max was expressed per kilogram lean body mass, both back strength and VO2max contributed significantly to the prediction of spine density in men, and the coefficient of determination R2 increased to 0.30. We conclude that body mass and grip strength, but not aerobic capacity, significantly predict bone density in elderly women. In elderly men, back strength is a more robust predictor of axial bone density than traditional expressions of aerobic capacity, but VO2max per kilogram lean mass and back strength both make significant contributions to the prediction of spine mineral density. The applicability of these results to younger men and women is uncertain.
我们评估了91名年龄在61至84岁的健康男性和女性的身体成分、最大有氧能力（VO2max）以及肌肉力量与骨矿物质密度之间的关系。瘦体重通过两种独立的脂肪量测量方法估算得出，即生物电阻抗法和皮褶厚度测量法。VO2max通过跑步机测力计直接测量耗氧量来确定。握力和背力通过等长测力法测量。腰椎和桡骨中部的矿物质密度通过双能和单能光子吸收法测量。男性的瘦体重、肌肉力量、有氧能力和骨密度显著高于女性。在女性中，握力与前臂和脊柱密度相关（r = 0.37，r = 0.28，p < 0.05）。在男性中，握力与前臂密度相关（r = 0.47，p < 0.05），背力与脊柱（r = 0.46，p < 0.01）和前臂密度均显著相关（r = 0.46，p < 0.01）。在女性中，前臂和脊柱密度与有氧能力均无显著相关性。在男性中，桡骨中部密度与耗氧量无显著相关性，但脊柱密度与VO2max之间的简单相关性显著（r = 0.41，p < 0.05）。男性的背力与VO2max显著相关（r = 0.47，p < 0.01）。通过逐步多元回归分析，背力成为脊柱矿物质最有力的预测指标，解释了骨密度变化的19%。将VO2max加入回归分析并未增加显著的预测价值。然而，当以每千克瘦体重表示VO2max时，背力和VO2max对男性脊柱密度的预测均有显著贡献，决定系数R2增至0.30。我们得出结论，体重和握力而非有氧能力能显著预测老年女性的骨密度。在老年男性中，背力比传统的有氧能力指标更能有力地预测轴向骨密度，但每千克瘦体重的VO2max和背力对脊柱矿物质密度的预测均有显著贡献。这些结果对年轻男性和女性的适用性尚不确定。
