Comparison of muscle quality and functional capacity between Japanese and Brazilian older individuals

• Published in: PloS one Vol. 15; no. 12; p. e0243589
• Main Authors: Akima, Hiroshi, Yoshiko, Akito, Radaelli, Régis, Ogawa, Madoka, Shimizu, Kaori, Tomita, Aya, Maeda, Hisashi, Neske, Rodrigo, Teodoro, Juliana, Maeda, Kazuhiro, Tanaka, Noriko, Pinto, Ronei
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 16.12.2020; Public Library of Science (PLoS)
• Subjects: Abnormalities; Adipose tissue; African Americans; Age; Aged; Aged, 80 and over; Aging; Biology and Life Sciences; Body composition; Body fat; Body mass; Body Mass Index; Body size; Brazil; Comparative analysis; Connective tissues; Demographic aspects; Dependent variables; Exercise; Female; Health aspects; Humans; Independent variables; Insulin resistance; Japan; Laboratories; Lean body mass; Male; Medicine and Health Sciences; Men; Metabolic disorders; Morphology; Muscle Strength; Muscle, Skeletal - physiology; Muscles; Musculoskeletal system; People and places; Physical characteristics; Physical fitness; Physiological aspects; Physiology; Quadriceps muscle; Quadriceps Muscle - physiology; Questionnaires; Regression analysis; Research and Analysis Methods; Risk analysis; Risk factors; Sport science; Subcutaneous Fat - physiology; Teacher education; Thickness; Ultrasonography; Women; Womens health; Brazil; Japan
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0243589

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.