Matsui Yasumoto, Takemura Marie, Harada Atsushi, Ando Fujiko, Shimokata Hiroshi
Department of Orthopedic Surgery, National Center for Geriatrics and Gerontology, 35 Gengo, Morioka-cho, Obu, Aichi, 474-8511, Japan,
J Bone Miner Metab. 2014 Sep;32(5):550-5. doi: 10.1007/s00774-013-0528-8. Epub 2013 Nov 7.
The association of knee extensor muscle strength with bone mineral density (BMD) has been reported in cross-sectional epidemiological studies, but it remains unclear whether or not this is the case with longitudinal change. Thus, we investigated whether or not the knee extension strength can predict the incidence of osteopenia or osteoporosis after 6 years, then compared the difference between sexes. Subjects were 1255 community-dwelling Japanese men and menopaused women, aged 40-81 years. BMD of lumbar spine and femoral neck was assessed by dual-energy X-ray absorptiometry twice at 6-year intervals. Subjects were divided into three groups, normal, osteopenia, and osteoporosis, depending on their young adult mean BMD % value. In the cross-sectional analysis the correlations between the knee extension strength and BMD of the two regions were examined, using Pearson's correlation coefficient. Longitudinal analyses were then conducted to determine the odds ratio, controlled for age and BMI, given that those who were normal in the initial stage developed osteopenia or osteoporosis after 6 years, for every 1 SD decrease in knee extension strength, as well as those who first had normal or osteopenia and then developed osteoporosis. Cross-sectional analysis showed a statistically significant relation between knee extensor muscle strength and BMD at both the lumbar spine (p = 0.02) and the femoral neck (p < 0.0001) only in men. The longitudinal analysis showed the significant effect of muscle strength on the loss of femoral neck BMD from normal to osteopenia or osteoporosis both in men (OR 1.84, 95 % CI 1.36-2.48, p < 0.0001) and in women (OR 1.29, 95 % CI 1.002-1.65, p < 0.05), as well as on the loss of spinal BMD from normal or osteopenia to osteoporosis only in men (OR 2.97, 95 % CI 1.07-8.23, p < 0.05). The results suggest the importance of knee extension strength to maintain the bone health of the proximal femur and spine in aging particularly in men.
横断面流行病学研究报告了膝伸肌力量与骨密度（BMD）之间的关联，但纵向变化是否如此仍不清楚。因此，我们调查了膝伸肌力量能否预测6年后骨质减少或骨质疏松的发生率，然后比较了性别差异。研究对象为1255名年龄在40 - 81岁的日本社区居住男性和绝经后女性。采用双能X线吸收法，每隔6年对腰椎和股骨颈的骨密度进行两次评估。根据其年轻成人平均骨密度百分比值，将研究对象分为三组：正常组、骨质减少组和骨质疏松组。在横断面分析中，使用Pearson相关系数检验膝伸肌力量与两个部位骨密度之间的相关性。然后进行纵向分析，以确定在控制年龄和体重指数的情况下，对于初始阶段正常但6年后发展为骨质减少或骨质疏松的人群，膝伸肌力量每降低1个标准差的比值比，以及对于最初正常或骨质减少而后发展为骨质疏松的人群。横断面分析显示，仅在男性中，膝伸肌力量与腰椎（p = 0.02）和股骨颈（p < 0.0001）的骨密度之间存在统计学显著关系。纵向分析显示，肌肉力量对男性（比值比1.84，95%可信区间1.36 - 2.48，p < 0.0001）和女性（比值比1.29，95%可信区间1.002 - 1.65，p < 0.05）从正常到骨质减少或骨质疏松的股骨颈骨密度丧失均有显著影响，并且仅在男性中对从正常或骨质减少到骨质疏松的脊柱骨密度丧失有显著影响（比值比2.97，95%可信区间1.07 - 8.23，p < 0.05）。结果表明，膝伸肌力量对于维持老年人尤其是男性近端股骨和脊柱的骨骼健康具有重要意义。
