Associations between housing and psychological damage by earthquake and modifiable risk factors for dementia in general older adults: Tohoku Medical Megabank community‐based cohort study

Aim To evaluate the association between housing and psychological damage caused by the Great East Japan Earthquake (GEJE) and modifiable risk factors (MRFs) of dementia for general population of older adults. Methods This cross‐sectional study enrolled 29 039 community‐dwelling older adults (mean age 69.1 ± 2.9 years, 55.5% women). We evaluated disaster‐related damage (by complete or not complete housing damage) and psychological damage (by post‐traumatic stress reaction [PTSR]) after the GEJE using a self‐report questionnaire. MRFs encompassed the presence of depression, social isolation, physical inactivity, smoking, and diabetes. We examined the association between disaster‐related damage and MRFs using ordinary least squares and modified Poisson regression models adjusted for sociodemographic and health status variables. Results Complete housing damage and PTSR were identified in 2704 (10.0%) and 855 (3.2%) individuals, respectively. The number of MRFs was significantly larger for the individuals with complete housing damage (β = 0.23; 95% confidence interval [CI]: 0.19–0.27) and PTSR (β = 0.60; 95% CI: 0.53–0.67). Prevalence ratios (PRs) for depression and physical inactivity were higher in individuals with complete housing damage. The PRs for all domains of the MRFs were significantly higher in individuals with PTSR. Conclusions Housing and psychological damage caused by the GEJE were associated with an increased risk factor of dementia. To attenuate the risk of dementia, especially among older victims who have experienced housing and psychological damage after a disaster, multidimensional support across various aspects of MRFs is required. Geriatr Gerontol Int 2024; 24: 509–516 .