Relationship between characteristics of skeletal muscle and oral function in community-dwelling older women

Purpose: To examine the relationship between oral function and sarcopenia staging, including dynapenia and presarcopenia, in community-dwelling older adults. Methods: A cross-sectional study was performed in community-dwelling older women aged 65 years and above. We measured oral muscle strength using maximum tongue pressure, oral muscle performance using oral diadochokinesis, and subjective swallowing difficulties using the Eating Assessment Tool. We measured skeletal muscle mass and function and other variables. All participants were divided into 4 groups (normal, presarcopenia, dynapenia, and sarcopenia) using an algorithm that operationally defines sarcopenia staging by skeletal muscle characteristics. A general linear model was used to analyze differences in oral function among the 4 groups. Results: A total of 245 participants were enrolled (median age [IQR], 81.0 [75.0-85.0]). The proportion of normal participants and those with presarcopenia, dynapenia, and sarcopenia was 48.6% (n = 119), 9.4% (n = 23), 30.2% (n = 74), and 11.8% (n = 29), respectively. The sarcopenia and dynapenia groups had significantly lower maximum tongue pressure and oral diadochokinesis than the normal group. In the multivariate analysis, after adjusting for age, maximum tongue pressure and oral diadochokinesis were found to be significantly lower in the sarcopenia and dynapenia groups than in the normal group. Conclusions: In this study, participants with sarcopenia and dynapenia showed low oral function, and similar trends were indicated for oral function and skeletal muscle according to progression of sarcopenia staging. Future research should clarify the characteristics of swallowing-related muscles, including muscle mass, strength, and performance at each sarcopenia stage.