Department of Physical Therapy, Faculty of Health and Welfare, Tokushima Bunri University, 180 Hoji, Yamashiro-cho, Tokushima City, 770-8514, Japan.
Yoshinogawa Hospital, Itano-gun, Japan.
Eur Geriatr Med. 2022 Aug;13(4):789-794. doi: 10.1007/s41999-022-00652-2. Epub 2022 May 10.
The extracellular water-to-total body water ratio (ECW/TBW) is used in bioelectrical impedance analysis (BIA) for measuring muscle mass; however, ECW/TBW may be affected by several factors common in older individuals. Here, we assessed the relationships of ECW/TBW with handgrip strength, gait speed, and skeletal muscle mass index (SMI) in older women.
In this cross-sectional study, 73 community-dwelling women aged ≥ 65 years who could independently perform activities of daily living were included. ECW/TBW was measured using direct segmental multifrequency BIA. The participants were divided into ECW/TBW < 0.40 (n = 54) and ECW/TBW ≥ 0.40 (n = 19) groups, with the latter indicating overhydration. SMI was calculated as appendicular skeletal muscle mass/(height) (kg/m). The relationships of SMI with handgrip strength and gait speed were assessed using partial correlation coefficients. Age, number of medications, pain, and medical history were treated as control variables.
The average age of participants was 77.6 ± 6.0 years. The SMI was significantly related to handgrip strength (partial correlation coefficient = 0.293, P = 0.016) but not to gait speed (partial correlation coefficient = - 0.183, P = 0.138). Similarly, the SMI of the ECW/TBW < 0.40 group was significantly related to handgrip strength (partial correlation coefficient = 0.372, P = 0.009) but not gait speed (partial correlation coefficient = - 0.267, P = 0.066); however, the SMI of the ECW/TBW ≥ 0.40 group was not related to either variable.
ECW/TBW represents a confounding factor, which should be considered when using BIA for sarcopenia diagnosis.
细胞外液与总体水比值（ECW/TBW）用于生物电阻抗分析（BIA）测量肌肉量；然而，ECW/TBW 可能受到老年人常见的多种因素的影响。在这里，我们评估了 ECW/TBW 与手握力、步态速度和骨骼肌质量指数（SMI）在老年女性中的关系。
在这项横断面研究中，纳入了 73 名年龄≥65 岁、能够独立完成日常生活活动的社区居住女性。使用直接节段多频 BIA 测量 ECW/TBW。参与者被分为 ECW/TBW<0.40（n=54）和 ECW/TBW≥0.40（n=19）两组，后者表示存在水过多。SMI 计算为四肢骨骼肌质量/（身高）（kg/m）。使用偏相关系数评估 SMI 与手握力和步态速度的关系。年龄、用药数量、疼痛和病史作为控制变量。
参与者的平均年龄为 77.6±6.0 岁。SMI 与手握力显著相关（偏相关系数=0.293，P=0.016），但与步态速度无关（偏相关系数=-0.183，P=0.138）。同样，ECW/TBW<0.40 组的 SMI 与手握力显著相关（偏相关系数=0.372，P=0.009），但与步态速度无关（偏相关系数=-0.267，P=0.066）；然而，ECW/TBW≥0.40 组的 SMI 与这两个变量均无关。
ECW/TBW 是一个混杂因素，在使用 BIA 诊断肌少症时应予以考虑。
