Division of Rheumatology, Philadelphia Veterans Affairs Medical Center, Pennsylvania.
School of Medicine, University of Pennsylvania, Philadelphia.
J Gerontol A Biol Sci Med Sci. 2018 Jun 14;73(7):946-952. doi: 10.1093/gerona/glx064.
We assessed the discrimination of lean mass estimates that have been adjusted for adiposity for physical functioning deficits and prediction of incident disability.
Included were 2,846 participants from the Health, Aging and Body Composition Study with available whole-body dual energy absorptiometry measures of appendicular lean mass index (ALMI, kg/m2) and fat mass index (FMI, kg/m2). Age-, sex-, and race-specific Z-Scores and T-Scores were determined by comparison to published reference ranges. ALMI values were adjusted for FMI (ALMIFMI) using a novel published method. Sex-stratified analyses assessed associations between lean mass estimates and the physical performance score, ability to complete a 400-meter walk, grip strength, and incident disability. Dichotomized definitions of low lean for age and sarcopenia were examined and their performance compared to the ALM-to-BMI ratio.
Compared to ALMI T-Scores and Z-Scores, the ALMIFMI scores demonstrated stronger associations with physical functioning, and were similarly associated with grip strength. Greater FMI Z-Scores and T-Scores were associated with poor physical functioning and incident disability. Definitions of low lean for age and sarcopenia using ALMIFMI (compared to ALMI) better discriminated those with poor physical functioning and a greater risk of incident disability. The ALM-to-BMI ratio was modestly associated with grip strength and physical performance, but was not associated with completion of the 400-meter walk or incident disability, independent of adiposity and height.
Estimation of skeletal muscle mass relative to adiposity improves correlations with physical performance and prediction of incident disability suggesting it is an informative outcome for clinical studies.
我们评估了调整体脂后的瘦体重估计值在身体机能缺陷和预测残疾事件方面的区分能力。
纳入了来自健康、老龄化和身体成分研究的 2846 名参与者，这些参与者有全身双能吸收法测量的四肢瘦体重指数（ALMI，kg/m2）和脂肪质量指数（FMI，kg/m2）。通过与已发表的参考范围进行比较，确定了年龄、性别和种族特异性 Z 分数和 T 分数。使用一种新的已发表方法，根据 FMI 调整了 ALMI 值（ALMIFMI）。按性别分层分析评估了瘦体重估计值与身体表现评分、完成 400 米步行的能力、握力和残疾事件之间的关系。检查了年龄相关低瘦和肌肉减少症的二分定义，并比较了它们与 ALM 与 BMI 比值的表现。
与 ALMI T 分数和 Z 分数相比，ALMIFMI 分数与身体机能的相关性更强，与握力的相关性也相似。较高的 FMI Z 分数和 T 分数与较差的身体机能和残疾事件相关。使用 ALMIFMI（与 ALMI 相比）定义年龄相关低瘦和肌肉减少症可以更好地区分身体机能较差和残疾事件风险较高的人群。ALM 与 BMI 比值与握力和身体表现有一定的相关性，但与完成 400 米步行或残疾事件无关，独立于肥胖和身高。
相对于肥胖，估计骨骼肌量与身体机能的相关性更好，预测残疾事件的能力也更好，这表明它是临床研究中有意义的结果。
