Cheese Consumption and Incidence of Dementia in Community-Dwelling Older Japanese Adults: The JAGES 2019–2022 Cohort Study

Background/Objectives: Dementia is a growing public health concern in rapidly aging Japan. Dietary factors, including dairy products, have been proposed as modifiable influences on cognitive health, although findings across studies remain inconsistent. This study aimed to examine the association between habitual cheese consumption and incident dementia in a large, population-based cohort of older Japanese adults, and to provide epidemiological evidence regarding its potential preventive role in populations with low baseline dairy intake. Methods: We analyzed data from the Japan Gerontological Evaluation Study (JAGES) 2019–2022 cohort, linking survey responses to long-term care insurance (LTCI) certification records. Participants aged ≥65 years without prior LTCI certification were included. Cheese consumption was assessed at baseline and categorized as ≥1 time/week vs. non-consumers. Propensity score matching (PSM) was applied on sociodemographic and health-related covariates. Cox proportional hazards models estimated hazard ratios (HRs) for incident dementia over three years. Results: After PSM, 7914 participants were analyzed (3957 consumers; 3957 non-consumers). Baseline covariates were well-balanced. Over 3 years, 134 consumers (3.4%) and 176 non-consumers (4.5%) developed dementia, corresponding to an absolute risk difference of 1.06 percentage points. Cheese consumption was associated with a lower hazard of dementia (HR = 0.76, 95% CI 0.60–0.95, p = 0.015). Conclusions: Habitual cheese consumption (≥1 time/week) was modestly associated with a reduced 3-year incidence of dementia in older Japanese adults. While the absolute risk reduction was small, these findings are consistent with prior observational evidence linking dairy intake to cognitive health. Further research is warranted to clarify dose–response relationships, cheese subtypes, and underlying mechanisms.