Department of Internal Medicine, Section of Gerontology and Geriatrics, VU University Medical Center, Postbus 7057, 1007, Amsterdam, The Netherlands.
Osteoporos Int. 2013 Oct;24(10):2681-91. doi: 10.1007/s00198-013-2376-8. Epub 2013 May 7.
Currently used diagnostic measures for sarcopenia utilize different measures of muscle mass, muscle strength, and physical performance. These diagnostic measures associate differently to bone mineral density (BMD), as an example of muscle-related clinical outcome. These differences should be taken into account when studying sarcopenia.
Diagnostic measures for sarcopenia utilize different measures of muscle mass, muscle strength, and physical performance. To understand differences between these measures, we determined the association with respect to whole body BMD, as an example of muscle-related clinical outcome.
In the European cross-sectional study MYOAGE, 178 young (18-30 years) and 274 healthy old participants (69-81 years) were recruited. Body composition and BMD were evaluated using dual-energy X-ray densitometry. Diagnostic measures for sarcopenia were composed of lean mass as percentage of body mass, appendicular lean mass (ALM) as percentage of body mass, ALM divided by height squared (ALM/height(2)), knee extension torque, grip strength, walking speed, and Timed Up and Go test (TUG). Linear regression models were stratified for sex and age and adjusted for age and country, and body composition in separate models.
Lean mass and ALM/height(2) were positively associated with BMD (P < 0.001). Significance remained in all sex and age subgroups after further adjustment for fat mass, except in old women. Lean mass percentage and ALM percentage were inversely associated with BMD in old women (P < 0.001). These inverse associations disappeared after adjustment for body mass. Knee extension torque and handgrip strength were positively associated with BMD in all subgroups (P < 0.01), except in old women. Walking speed and TUG were not related to BMD.
The associations between diagnostic measures of sarcopenia and BMD as an example of muscle-related outcome vary widely. Differences between diagnostic measures should be taken into account when studying sarcopenia.
目前用于肌少症的诊断方法使用了不同的肌肉质量、肌肉力量和身体表现测量指标。这些诊断方法与骨矿物质密度（BMD）的关联不同，BMD 是肌肉相关临床结果的一个例子。在研究肌少症时，应考虑这些差异。
肌少症的诊断方法使用了不同的肌肉质量、肌肉力量和身体表现测量指标。为了了解这些指标之间的差异，我们确定了它们与全身 BMD 的相关性，BMD 是肌肉相关临床结果的一个例子。
在欧洲的横断面研究 MYOAGE 中，招募了 178 名年轻（18-30 岁）和 274 名健康老年人（69-81 岁）。使用双能 X 射线吸收法评估身体成分和 BMD。肌少症的诊断方法由身体质量的瘦体重百分比、身体质量的四肢瘦体重百分比、四肢瘦体重除以身高的平方（ALM/height(2)）、膝关节伸展扭矩、握力、步行速度和计时起立行走测试（TUG）组成。线性回归模型按性别和年龄分层，并在单独的模型中按年龄和国家以及身体成分进行调整。
瘦体重和 ALM/height(2)与 BMD 呈正相关（P < 0.001）。在进一步调整脂肪质量后，除老年女性外，所有性别和年龄亚组的相关性仍然显著。老年女性的瘦体重百分比和四肢瘦体重百分比与 BMD 呈负相关（P < 0.001）。这些负相关在调整体重后消失。膝关节伸展扭矩和握力在所有亚组中与 BMD 呈正相关（P < 0.01），除了老年女性。步行速度和 TUG 与 BMD 无关。
肌少症诊断方法与 BMD 之间的关联差异很大，BMD 是肌肉相关结果的一个例子。在研究肌少症时，应考虑诊断方法之间的差异。
