Effects of physical and social environments on the risk of dementia among Taiwanese older adults

Background: Physical and social environments may influence cognition health in older adults. However, evidence regarding physical and social environments linked to dementia is lacking, especially in Asia. This study aims to explore the influence of physical and social environments on the incidence of dementia through a population-based case-control design in Taiwan. Methods: We identified 26,206 incident cases with dementia aged≧65 years in 2010, with the same no. of controls from National Health Insurance claims. Environmental measures were collected from government statistics including three physical environments and three social environments. Multilevel logistic regression was used to estimate the odds ratios (ORs) and 95% confidence intervals (CI) of the association between dementia incidence and the environmental measures at the township level. Results: We observed a significant reduction of 12% in the odds ratios of dementia in areas with higher availability of playgrounds and sport venues (OR 0.88, 95% CI 0.81-0.95), after controlling for individual and other environmental characteristics. Community center availability was also significantly associated with an 8% decreased odds for dementia (OR 0.92, 95% CI 0.87-0.99), but the association was not significant after further consideration of individual-level characteristics. Although higher odds of dementia were found in areas with high median annual family income (OR 1.14, 95% CI 1.04-1.25), such a significant relationship did not appear in the full model. Conclusions: Our study suggests that specific physical and social environmental features have different influences on the risk of dementia. Public health interventions may consider these environmental aspects for preventing dementia incidence.