Association between Japanese Diet Adherence and Muscle Weakness in Japanese Adults Aged ≥50 Years: Findings from the JSTAR Cohort Study.

Japanese diet adherence has been inversely correlated with muscle weakness. In this study, we aimed to validate that association. Longitudinal data from 1699 individuals aged ≥50 years (mean age 62.5 ± 6.9 years, 50.4% female) at two time points (2007 and 2011) were used. Participants without muscle weakness from several regions in Japan were included. The 12-component revised Japanese Diet Index (rJDI12) classified by tertiles assessed adherence to the Japanese dietary pattern. Muscle weakness was defined as a handgrip strength of ˂18 kg for females and ˂28 kg for males based on the Asian Working Group for Sarcopenia criteria 2019. A multivariate logistic approach was used to determine the relationship between rJDI12 tertile and the occurrence of muscle weakness by calculating the odds ratio (OR) and its 95% confidence interval (95% CI) throughout the observation period. Muscle weakness was negatively correlated with the highest rJDI12 tertile (OR [95% CI] 0.891 [0.814, 0.973] for T3). This association was consistent in sensitivity analyses with multiple imputations of missing values. Closely following the Japanese dietary pattern appears to reduce the occurrence of muscle weakness among the aging population in this study, suggesting it may prevent frailty and sarcopenia in the aging population.