Types of Exercise and Risk of Developing Dementia in Older Japanese Community-Dwelling Adults: A Prospective Study.

AIM: Although exercise is considered effective in preventing dementia, it remains unclear whether different types of exercise are differentially associated with dementia risk. The aim of this study was to clarify the relationship between specific types of exercise and the risk of developing dementia. METHODS: We conducted postal surveys of 5074 community-dwelling older adults in Japan in June 2013 (pre-baseline wave) and August 2017 (baseline wave). Participants were followed for 4 years, until July 2021. Dementia was assessed using the nationally standardized scale developed by the Ministry of Health, Labour and Welfare of Japan. Participants were grouped based on engagement in 17 exercise types or classified as a non-exerciser group if they did not participate in any of these activities. Five exercise types with ≥ 150 participants-calisthenics, walking, Japanese croquet, golf, and strength exercise-were included in the analysis. Adjusted Cox proportional hazards models with robust variance estimators were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for dementia development by comparing each exercise group with the non-exerciser group. RESULTS: During the follow-up period (median, 4.0 years; interquartile range, 4.0-4.0 years), 430 participants (8.5%) developed dementia. Compared with non-exercisers, participation in Japanese croquet and strength exercise was associated with a significantly lower risk of developing dementia, with adjusted HRs of 0.68 (95% CI, 0.46-0.99) and 0.26 (95% CI, 0.08-0.81), respectively. CONCLUSIONS: Participation in Japanese croquet and strength exercise may be beneficial for the prevention of dementia.