Ismail Catheeja, Zabal Johannah, Hernandez Haniel J, Woletz Paula, Manning Heather, Teixeira Carla, DiPietro Loretta, Blackman Marc R, Harris-Love Michael O
Muscle Morphology, Mechanics and Performance Laboratory, Clinical Research Center - Human Performance Research Unit, Veterans Affairs Medical Center Washington, DC, USA ; Department of Medicine, School of Medicine and Health Sciences, The George Washington University Washington, DC, USA.
Department of Physical Therapy and Health Care Sciences, School of Medicine and Health Sciences, The George Washington University Washington, DC, USA ; Department of Health Sciences, Malek School of Health Professions, Marymount University Arlington, VA, USA.
Front Physiol. 2015 Oct 29;6:302. doi: 10.3389/fphys.2015.00302. eCollection 2015.
Age-related changes in muscle mass and muscle tissue composition contribute to diminished strength in older adults. The objectives of this study are to examine if an assessment method using mobile diagnostic ultrasound augments well-known determinants of lean body mass (LBM) to aid sarcopenia staging, and if a sonographic measure of muscle quality is associated with muscle performance.
Twenty community-dwelling female subjects participated in the study (age = 43.4 ± 20.9 years; BMI: 23.8, interquartile range: 8.5). Dual energy X-ray absorptiometry (DXA) and diagnostic ultrasound morphometry were used to estimate LBM. Muscle tissue quality was estimated via the echogenicity using grayscale histogram analysis. Peak force was measured with grip dynamometry and scaled for body size. Bivariate and multiple regression analyses were used to determine the association of the predictor variables with appendicular lean mass (aLM/ht(2)), and examine the relationship between scaled peak force values and muscle echogenicity. The sarcopenia LBM cut point value of 6.75 kg/m(2) determined participant assignment into the Normal LBM and Low LBM subgroups.
The selected LBM predictor variables were body mass index (BMI), ultrasound morphometry, and age. Although BMI exhibited a significant positive relationship with aLM/ht(2) (adj. R (2) = 0.61, p < 0.001), the strength of association improved with the addition of ultrasound morphometry and age as predictor variables (adj. R (2) = 0.85, p < 0.001). Scaled peak force was associated with age and echogenicity (adj. R (2) = 0.53, p < 0.001), but not LBM. The Low LBM subgroup of women (n = 10) had higher scaled peak force, lower BMI, and lower echogenicity values in comparison to the Normal LBM subgroup (n = 10; p < 0.05).
Diagnostic ultrasound morphometry values are associated with LBM, and improve the BMI predictive model for aLM/ht(2) in women. In addition, ultrasound proxy measures of muscle quality are more strongly associated with strength than muscle mass within the study sample.
肌肉质量和肌肉组织组成的年龄相关变化导致老年人力量下降。本研究的目的是检验使用移动诊断超声的评估方法是否能增强已知的瘦体重（LBM）决定因素以辅助肌肉减少症分期，以及肌肉质量的超声测量值是否与肌肉功能相关。
20名社区居住的女性受试者参与了本研究（年龄 = 43.4 ± 20.9岁；BMI：23.8，四分位间距：8.5）。采用双能X线吸收法（DXA）和诊断超声形态测量法估计LBM。通过灰度直方图分析的回声性估计肌肉组织质量。用握力计测量峰值力并根据身体大小进行标化。采用双变量和多元回归分析确定预测变量与上肢瘦体重（aLM/ht(2)）的关联，并检验标化峰值力值与肌肉回声性之间的关系。根据肌肉减少症LBM切点值6.75 kg/m(2)将参与者分为正常LBM亚组和低LBM亚组。
所选的LBM预测变量为体重指数（BMI）、超声形态测量值和年龄。尽管BMI与aLM/ht(2)呈显著正相关（调整后R(2) = 0.61，p < 0.001），但加入超声形态测量值和年龄作为预测变量后，关联强度有所改善（调整后R(2) = 0.85，p < 0.001）。标化峰值力与年龄和回声性相关（调整后R(2) = 0.53，p < 0.001），但与LBM无关。与正常LBM亚组（n = 10）相比，低LBM亚组的女性（n = 10）标化峰值力更高、BMI更低且回声性值更低（p < 0.05）。
诊断超声形态测量值与LBM相关，并改善了女性aLM/ht(2)的BMI预测模型。此外，在研究样本中，肌肉质量的超声替代测量值与力量的关联比与肌肉量的关联更强。
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