Religious affiliation and the risk of dementia in Taiwanese elderly.

Introduction: Religious affiliations vary across ethnic groups because of different cultural backgrounds. Some studies have explored the association between religious affiliation and cognitive decline. Only a small portion of patients with cognitive decline progress to dementia. However, the association between religious affiliation and dementia risk remains unclear.

Methods: In this case-control study, we recruited 280 patients with Alzheimer's disease (AD) and 138 with vascular dementia (VaD) (both aged ≥60 years) from three teaching hospitals in northern Taiwan between 2007 and 2010. Age-matched healthy controls (n=466) were recruited from an elderly health checkup program and from volunteers visiting the hospital during the same period. Three religious affiliations-Taoism, Buddhism, and Christianity-were evaluated. The study also assessed the effect of important factors such as gender or leisure activities on the association of religious affiliation with dementia risk.

Results: Participants with Christianity affiliation showed decreased AD risk (adjusted odds ratio [AOR]=0.46, 95% confidence interval [CI]=0.25-0.87) compared with those without any religious affiliation. Moreover, this effect was stronger in women (AOR=0.38, 95% CI=0.15-0.92) and in participants who exercised regularly (>3 times/week; AOR=0.33, 95% CI=0.14-0.77). No significant association was observed among participants with Taoism and Buddhism affiliations. Affiliation to none of the religions was associated with VaD risk.

Conclusions: Thus, Chinese participants having Christianity affiliation showed decreased AD risk. Moreover, the protective effect was more evident in women and in participants who exercised regularly.