Kim Jaehee, Wang ZiMian, Heymsfield Steven B, Baumgartner Richard N, Gallagher Dympna
Obesity Research Center, St Luke's-Roosevelt Hospital and the Institute of Human Nutrition, Columbia University, College of Physicians and Surgeons, New York, NY 10025, USA.
Am J Clin Nutr. 2002 Aug;76(2):378-83. doi: 10.1093/ajcn/76.2.378.
Skeletal muscle (SM) is an important body-composition component that remains difficult and impractical to quantify by most investigators outside of specialized research centers. A large proportion of total-body SM is found in the extremities, and a large proportion of extremity lean soft tissue is SM. A strong link should thus exist between appendicular lean soft tissue (ALST) mass and total-body SM mass.
The objective was to develop prediction models linking ALST estimated by dual-energy X-ray absorptiometry (DXA) with total-body SM quantified by multislice magnetic resonance imaging in healthy adults.
ALST and total-body SM were evaluated with a cross-sectional design in adults [body mass index (in kg/m(2)) < 35] with an SM-prediction model developed and validated in model-development and model-validation groups, respectively. The model-development and model-validation groups included 321 and 93 ethnically diverse adults, respectively.
ALST alone was highly correlated with total-body SM (model 1: R(2) = 0.96, SEE = 1.63 kg, P < 0.001), although multiple regression analyses showed 2 additional predictor variables: age (model 2: 2-variable combined R(2) = 0.96, SEE = 1.58 kg, P < 0.001) and sex (model 3: 3-variable combined R(2) = 0.96, SEE = 1.58 kg, P < 0.001). All 3 models performed well in the validation group. An SM-prediction model based on the SM-ALST ratio was also developed, although this model had limitations when it was applied across all subjects.
Total-body SM can be accurately predicted from DXA-estimated ALST, thus affording a practical means of quantifying the large and clinically important SM compartment.
骨骼肌（SM）是身体组成的重要部分，但对于大多数非专业研究中心的研究人员来说，对其进行量化仍然困难且不切实际。全身大部分的SM位于四肢，而四肢的瘦软组织大部分是SM。因此，上肢瘦软组织（ALST）质量与全身SM质量之间应该存在紧密联系。
目的是建立预测模型，将通过双能X线吸收法（DXA）估计的ALST与健康成年人通过多层磁共振成像量化的全身SM联系起来。
采用横断面设计对成年人[体重指数（kg/m²）<35]的ALST和全身SM进行评估，分别在模型开发组和模型验证组中开发并验证SM预测模型。模型开发组和模型验证组分别包括321名和93名不同种族的成年人。
单独的ALST与全身SM高度相关（模型1：R² = 0.96，标准误 = 1.63 kg，P < 0.001），尽管多元回归分析显示还有另外两个预测变量：年龄（模型2：两变量组合R² = 0.96，标准误 = 1.58 kg，P < 0.001）和性别（模型3：三变量组合R² = 0.96，标准误 = 1.58 kg，P < 0.001）。所有三个模型在验证组中表现良好。还开发了基于SM-ALST比值的SM预测模型，尽管该模型在应用于所有受试者时存在局限性。
可以从DXA估计的ALST准确预测全身SM，从而提供了一种量化庞大且具有临床重要性的SM成分的实用方法。
