The Longitudinal Associations of Denture Use and Subjective Chewing Difficulty with Depressive Symptoms Among Middle-Aged and Older Adults: A Sex-Stratified Analysis of the Korean Longitudinal Study of Aging (2006–2022)

Background/Objectives: Evidence from repeated-measures studies examining denture use, subjective chewing difficulty, and depressive symptoms remains limited. This study examined the population-averaged associations of denture use and subjective chewing difficulty with depressive symptoms across nine waves of the Korean Longitudinal Study of Aging (KLoSA). Methods: Data from 10,137 participants contributing 68,937 person-wave observations across nine KLoSA waves (2006–2022) were analyzed. Depressive symptoms were assessed using the 10-item Center for Epidemiologic Studies Depression Scale (CESD-10). Generalized estimating equations (GEEs) were used to account for repeated observations within participants. Sex-stratified analyses and formal interaction tests were additionally performed. Results: In adjusted sex-stratified analyses, denture use was associated with a higher expected mean CESD-10 score among women [exp(B) = 1.068, 95% CI: 1.044–1.092] but not among men. Greater subjective chewing difficulty was consistently associated with higher expected mean CESD-10 scores among both men and women and among both denture users and non-denture users. The sex × denture use interaction was significant [exp(B) = 1.064, 95% CI: 1.043–1.085, p < 0.001], and sex × subjective chewing difficulty interactions were also significant among both denture users and non-denture users (all p ≤ 0.001). Conclusions: Greater subjective chewing difficulty was consistently associated with higher depressive symptom levels across repeated observations among both denture users and non-denture users. Sex modified the associations of denture use and subjective chewing difficulty with depressive symptoms. Perceived chewing function may provide additional information beyond denture status when assessing oral health-related vulnerability associated with depressive symptoms; however, temporal direction and causality cannot be inferred from these analyses.