Longitudinal association between chewing difficulty and possible sarcopenia in middle-aged and older adults: A 17-year national longitudinal study.

Sarcopenia is a key public health concern that reduces older-adult quality of life and is associated with adverse outcomes, including falls and chronic diseases. Although interest in the oral health-sarcopenia association has increased, most prior studies have used cross-sectional designs, limiting assessment of temporal precedence. Using data from the 1st to 9th waves (2006-2022) of the Korean Longitudinal Study of Aging, this study investigated the longitudinal association and temporal directionality between chewing difficulty and possible sarcopenia in middle-aged and older adults. After adjustment for confounding variables, older adults with chewing difficulty had a significantly higher odds of possible sarcopenia compared to those without chewing difficulty (OR, 1.616; 95% CI, 1.507-1.733). Subgroup analyses indicated a stronger association in females than in males and, in particular, among non-current smokers and non-current drinkers. Lagged effect models further identified a bidirectional relationship between chewing difficulty and possible sarcopenia; nonetheless, the effect of prior chewing difficulty on subsequent possible sarcopenia (OR, 1.390; 95% CI, 1.284-1.504) was statistically and significantly stronger than the reverse effect (OR, 1.154; 95% CI, 1.060-1.255). In conclusion, this longitudinal study identified chewing difficulty as a significant predictor of sarcopenia in older Korean individuals. Although the relationship was bidirectional, chewing difficulty had the more dominant precursor effect on sarcopenia.