Relationship Between Swallowing Frequency and Swallowing-Related Muscle Mass in Older Adults.

Older adults have decreased swallowing-related muscle mass, which may lead to decreased swallowing function. One of the causes of this decrease in muscle mass in older adults is a decrease in swallowing frequency. The purpose of this study was to evaluate the relationship between swallowing frequency and swallowing-related muscle mass. The study included 84 older adults residing in long-term care beds or elderly care facilities. The correlation between swallowing frequency measured by detecting swallowing sounds from laryngeal sounds and the coronal cross-sectional area of the geniohyoid muscle (GM) measured using an ultrasound diagnostic device was examined. Additionally, multiple regression analysis was used to examine the relationship between GM muscle mass and factors that may influence muscle mass, including sex, age, nutrition (body mass index), total body muscle mass (thigh muscle thickness [TMT]) and swallowing frequency. A significant positive correlation (r = 0.437, p < 0.001) was found between swallowing frequency and GM mass. A multivariate analysis including other factors revealed that sex (β = 0.482, p < 0.001), TMT (β = 0.272, p < 0.005) and swallowing frequency (β = 0.193, p < 0.05) were significantly correlated with GM mass. The results of this study indicated that GM mass differed by sex and was correlated with whole-body muscle mass; furthermore, the findings suggest that it is also influenced by localised activity, specifically swallowing frequency.