Associations of Oral Functional Impairment, Nutritional Risk, and Functional Dependence with Dementia Among Community-Dwelling Older Koreans

Background: Dementia is a major geriatric syndrome associated with nutritional vulnerability and functional decline among older adults. This study aimed to compare oral functional impairment, nutritional risk, and functional dependence according to dementia status and to examine their associations with dementia among community-dwelling older Koreans. Methods: This cross-sectional study analyzed data from 10,078 adults aged ≥65 years who participated in the 2023 National Survey of Older Koreans. Dementia was defined based on self-reported physician diagnosis. Oral functional impairment, nutritional risk factors, and functional dependence, including activities of daily living (ADL) and instrumental activities of daily living (IADL), were assessed using structured survey questionnaires. Chi-square tests and multivariable logistic regression analyses were performed using four sequentially adjusted models. Results: Older adults with dementia exhibited significantly greater oral functional impairment, nutritional risk, and functional dependence than those without dementia. In the fully adjusted model, denture use remained independently associated with dementia (OR = 1.692, 95% CI: 1.179–2.428). Fewer than two meals per day (OR = 3.156, 95% CI: 1.771–5.623) and difficulty shopping for or preparing meals (OR = 2.408, 95% CI: 1.648–3.520) were significantly associated with dementia. In addition, severe ADL dependence (OR = 5.895, 95% CI: 2.947–11.794) and IADL dependence (OR = 4.598, 95% CI: 3.099–6.822) showed strong associations with dementia. Conclusions: Dementia was significantly associated with oral functional impairment, nutritional risk, and functional dependence, indicating multidimensional geriatric vulnerability and highlighting the need for integrated assessment in dementia care.