Association between self-reported difficulty in chewing or swallowing and frailty in older adults: A retrospective cohort study

Oral frailty can contribute to physical and mental health disorders. Previous research has shown an association between frailty and self-reported difficulty in chewing or swallowing. However, their combined assessment has obscured their specific impact on frailty-related outcomes. To investigate the independent associations between difficulty in chewing or swallowing and 1-year frailty outcomes, while also examining their interactions. This retrospective cohort study utilized the DeSC database to identify older adults aged ≥ 75 years who underwent health checkups between April 2014 and November 2022. Multivariate Cox regression analyses were conducted to assess the association between self-reported difficulty in chewing or swallowing and outcomes, including hospitalization due to aspiration pneumonia, all-cause hospitalization, and all-cause mortality within 1 year. Interactions between chewing and swallowing difficulties were also evaluated. Among 359,111 older adults, 39.0% reported oral function difficulties. Swallowing difficulty alone lacked significant outcome association. However, chewing difficulty alone was significantly associated with higher risks of hospitalization due to aspiration pneumonia (hazard ratio (HR), 1.35; 95% confidence interval (CI), 1.15-1.58; P < 0.001), all-cause hospitalization (HR, 1.08; 95% CI, 1.05-1.11; P < 0.001), and all-cause mortality (HR, 1.28; 95% CI, 1.14-1.44; P < 0.001) compared with no self-reported difficulty. A significant positive interaction between self-reported difficulty in chewing and swallowing was observed for all-cause mortality (P = 0.009). Self-reported difficulty in chewing was significantly associated with higher risks of hospitalization due to aspiration pneumonia, all-cause hospitalization, and all-cause mortality among older adults. Chewing and swallowing difficulties showed a synergistic effect, significantly increasing all-cause mortality risk.