Changes in activities of daily living according to oral function in Korean community-dwelling older adults: a follow-up study

Objectives: This study aimed to investigate the relationship between oral function and activities of daily living among older adults in Korea.Specifically, it examines how changes in oral health over time impact the Activities of Daily Living (ADL) and Instrumental Activities of Daily Living (IADL) scores using longitudinal data from the Korean Social Life, Health, and Aging Project (KSHAP).This study aims to identify the oral functions that significantly affect these abilities, thereby contributing to strategies for maintaining healthy aging.Methods: Data from the KSHAP Cohort K (Wave 4 in 2016 and Wave 5 in 2019) were analyzed.A total of 454 participants were included, after excluding those with incomplete data.Oral function was assessed using subjective self-reported measures of chewing and swallowing abilities, and salivary function.ADL and IADL were evaluated using Korean-specific tools (K-ADL and K-IADL, respectively), with higher scores indicating greater dependency.Statistical analyses included crosstabulations, independent t-tests, and generalized estimating equations (GEE) to assess the relationship between oral function and changes in ADL/IADL over time, with adjustments for covariates such as age, gender, socioeconomic status, and comorbidities.Results: Significant differences in ADL and IADL limitations were observed based on oral function.Participants with fewer teeth (0-10) were more likely to experience functional limitations than those with more teeth (21-32).Regression analyses using GEE revealed that difficulty in chewing (B=0.067,P=0.044) and swallowing (B=0.445,P<0.001) were associated with increased ADL dependency.For IADL, swallowing difficulty moderately affected dependency (B=0.234,P=0.003).These findings suggest that ADL limitations are more closely associated with oral function than are IADL limitations, highlighting the physiological importance of basic oral functions, such as chewing and swallowing, in daily activities.Conclusions: This study demonstrates that oral health plays a critical role in maintaining activities of daily living among older adults, with ADL being more affected than IADL.A decline in oral function, particularly in chewing and swallowing, is associated with greater dependency over time.These findings underscore the need for targeted oral health management strategies to support functional independence and the overall quality of life in older populations.Future research should explore the bidirectional causality and broader demographic representations to further substantiate these results.