Characteristics of Japanese Older Adults Whose Trunk Muscle Mass Decreased during the COVID-19 Pandemic

The coronavirus (COVID-19) pandemic significantly affected the physical and mental functions in older adults, resulting in "corona-frailty". This 2-year prospective study characterized changes in quantitative measures and corona-frailty among a cohort of community-dwelling older women. Changes were evaluated using face-to-face interactions with 39 Japanese women (mean age: 76.1 ± 5.9) in 2019 (pre-pandemic baseline) and 2021 (follow-up during the pandemic). Quantitative measurements of handgrip strength, walking speed, calf circumference, body composition, and background factors were evaluated. Body weight and trunk muscle mass significantly decreased at follow-up. Multiple regression analysis, using change in trunk muscle mass as the dependent variable and background factors as independent variables, identified that decrease in trunk muscle mass was associated with "being robust at baseline" and answering "Yes" to the question of "Do you go out less frequently compared with last year"? The 2-year trunk muscle mass change for each baseline frailty stage showed a significant decrease only in the robust group (-8.0%). The decrease in trunk muscle mass might be related to pandemic-induced lifestyle restraint, suggesting that robust older adults who are healthy and active should take measures that focus on trunk muscles to avoid "corona-frailty".