Participation in cognitively stimulating activities and risk of incident Alzheimer disease

Context Frequent participation in cognitively stimulating activities has been hypothesized to reduce risk of Alzheimer disease (AD), but prospective data regarding an association are lacking. Objective To test the hypothesis that frequent participation in cognitive activities is associated with a reduced risk of AD. Design Longitudinal cohort study with baseline evaluations performed between January 1994 and July 2001 and mean follow-up of 4.5 years. Participants and Setting A total of 801 older Catholic nuns, priests, and brothers without dementia at enrollment, recruited from 40 groups across the United States. At baseline, they rated frequency of participation in common cognitive activities (eg, reading a newspaper), from which a previously validated composite measure of cognitive activity frequency was derived. Main Outcome Measures Clinical diagnosis of AD by a board-certified neurologist using National Institute of Neurological and Communicative Disorders and Stroke/Alzheimer's Disease and Related Disorders Association criteria and change in global and specific measures of cognitive function, compared by cognitive activity scare at baseline. Results Baseline scores on the composite measure of cognitive activity ranged from 1.57 to 4.71 (mean, 3.57; SD, 0.55), with higher scores indicating more frequent activity. During an average of 4.5 years of follow-up, 111 persons developed AD. In a proportional hazards model that controlled for age, sex, and education, a 1-point increase in cognitive activity score was associated with a 33% reduction in risk of AD (hazard ratio, 0.67; 95% confidence interval, 0.49-0.92). Results were comparable when persons with memory impairment at baseline were excluded and when terms for the apolipoprotein E epsilon4 allele and other medical conditions were added. in random-effects models that controlled for age, sex, education, and baseline level of cognitive function, a 1-point increase in cognitive activity was associated with reduced decline in global cognition (by 47%), working memory (by 60%), and perceptual speed (by 30%). Conclusion These results suggest that frequent participation in cognitively stimulating activities is associated with reduced risk of AD.