Relationship between lifestyle diseases and oral function in older adults: The Toon Health Study.

PURPOSE: Lifestyle diseases are established risk factors for oral function decline; however, the age-dependent dynamics of these associations, specifically between "young-old" and "old-old" phases, remain unclear. This study investigated the relationship between six major lifestyle diseases and seven oral function measures across age strata to identify the critical windows for medical and dental intervention. METHODS: This cross-sectional analysis within the "Toon Health Study" recruited 395 community-dwelling individuals (mean age 68.8 ± 8.9 years), stratified into middle-aged, young-old, and old-old groups. Systemic status and oral function were evaluated using standard diagnostic criteria. Associations were analyzed using logistic regression models adjusted for age, sex, and family dentist status. The predicted probability plots visualized age-dependent associations. RESULTS: Logistic regression analysis revealed age-dependent associations between diabetes mellitus (DM) and oral hypofunction. Although DM showed a protective association in the old-old group (odds ratio [OR] = 0.28, P = 0.014), it significantly increased the risk of oral hypofunction in the young-old group (OR = 7.75, P = 0.003). Decreased masticatory function was significantly associated with DM and obesity (P < 0.05). Although these conditions increased the risk of decreased masticatory function in the young-old group, none of the participants with DM in the old-old group exhibited such an impairment. CONCLUSIONS: DM and OBE may exacerbate oral function decline in young-old individuals more strongly than aging itself, whereas continuous dental care may mitigate these effects in the old-old. This highlights the importance of integrating age-specific oral management with lifestyle disease prevention.