Health literacy as an explanatory factor in the association between life functioning scale and oral functional problems among older Koreans

This study examined the association between life functioning and oral functional problems among Korean adults aged ≥65 years and assessed whether health literacy serves as an explanatory factor in this association. We conducted a cross-sectional analysis using nationally representative data from 1,698 participants in the 2024 Korea National Health and Nutrition Examination Survey. Life functioning was measured using the Life Functioning Scale-10 (LFS-10), with higher scores indicating better functioning. Oral functional problems were assessed using self-reported chewing and speaking difficulty items, with higher scores indicating poorer oral function. Health literacy was measured using the 10-item Health Literacy Index for the Community. Survey-weighted linear regression models were adjusted for sociodemographic characteristics, health behaviors, and comorbidities, and cross-sectional explanatory associations were evaluated using complex-sample hierarchical regression. Participants with low LFS-10 scores reported greater oral functional problems than those with high scores (4.66 vs 3.89). In adjusted models, LFS-10 scores were inversely associated with oral functional problems (B = −0.050; p = 0.006) and positively associated with health literacy (B = 0.159; p < 0.001). After health literacy was added to the model, the coefficient for LFS-10 was modestly attenuated but remained statistically significant (B = −0.043; p = 0.016), while health literacy was inversely associated with oral functional problems (B = −0.050; p = 0.013). The attenuation was approximately 14%, with a small increase in explained variance (ΔR² = 0.009). These findings indicate that lower life functioning is associated with greater oral functional problems and that health literacy modestly explains this association; however, causality cannot be inferred because of the cross-sectional study design.