Research Center of Health, Physical Fitness & Sports, Nagoya University, Nagoya, Aichi, Japan.
Graduate School of Education & Human Development, Nagoya University, Nagoya, Aichi, Japan.
PLoS One. 2020 Dec 16;15(12):e0243589. doi: 10.1371/journal.pone.0243589. eCollection 2020.
Muscle quality is well-known to decrease with aging and is a risk factor for metabolic abnormalities. However, there is a lack of information on race-associated differences in muscle quality and other neuromuscular features related to functional performance. This study aimed to compare muscle quality, function, and morphological characteristics in Japanese and Brazilian older individuals. Eighty-four participants aged 65-87 years were enrolled in the study (42 Japanese: 23 men, 19 women, mean age 70.4 years; 42 Brazilians: 23 men, 19 women, mean age 70.8 years). Echo intensity (EI) and muscle thickness (MT) of the quadriceps femoris were measured using B-mode ultrasonography. A stepwise multiple linear regression analysis with EI as a dependent variable revealed that MT was a significant variable for Japanese participants (R2 = 0.424, P = 0.001), while MT and subcutaneous adipose tissue (SCAT) thickness were significant variables for Brazilian participants (R2 = 0.490, P = 0.001). A second stepwise multiple linear regression analysis was performed after excluding MT and SCAT thickness from the independent variables. Sex and age for Japanese participants (R2 = 0.381, P = 0.001) and lean body mass and body mass index for Brazilian participants (R2 = 0.385, P = 0.001) were identified as significant independent variables. The present results suggest that MT is closely correlated with muscle quality in Japanese and Brazilian older individuals. Increases in muscle size may induce decreases in intramuscular adipose tissue and/or connective tissues, which are beneficial for reducing the risks of metabolic impairments in Japanese and Brazilian older individuals.
肌肉质量随着年龄的增长而下降，是代谢异常的一个危险因素。然而，关于种族相关的肌肉质量差异以及与功能表现相关的其他神经肌肉特征的信息还很缺乏。本研究旨在比较日本和巴西老年人的肌肉质量、功能和形态特征。本研究纳入了 84 名年龄在 65-87 岁的参与者（42 名日本人：23 名男性，19 名女性，平均年龄 70.4 岁；42 名巴西人：23 名男性，19 名女性，平均年龄 70.8 岁）。使用 B 型超声测量股四头肌的回声强度（EI）和肌肉厚度（MT）。以 EI 为因变量的逐步多元线性回归分析显示，MT 是日本参与者的一个显著变量（R2 = 0.424，P = 0.001），而 MT 和皮下脂肪组织（SCAT）厚度是巴西参与者的显著变量（R2 = 0.490，P = 0.001）。在将 MT 和 SCAT 厚度从自变量中排除后，进行了第二次逐步多元线性回归分析。对于日本参与者，性别和年龄（R2 = 0.381，P = 0.001），以及对于巴西参与者，瘦体重和体重指数（R2 = 0.385，P = 0.001）是显著的独立变量。本研究结果表明，MT 与日本和巴西老年人的肌肉质量密切相关。肌肉大小的增加可能会导致肌肉内脂肪组织和/或结缔组织减少，这对降低日本和巴西老年人代谢损伤的风险是有益的。
