Frequent participation in cognitively stimulating activities has been hypothesized
to reduce risk of Alzheimer disease (AD), but prospective data regarding an association
are lacking.
To test the hypothesis that frequent participation in cognitive activities is associated
with a reduced risk of AD.
Longitudinal cohort study with baseline evaluations performed between January 1994
and July 2001 and mean follow-up of 4.5 years.
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.
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 score at baseline.
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%).
These results suggest that frequent participation in cognitively stimulating activities
is associated with reduced risk of AD.