Physical Activity and 5-Year Cognitive Decline in the Doetinchem Cohort Study

PURPOSE: It is hypothesized that the intensity of physical activity habits, rather than the time spent on those activities, might mediate cognitive function. This study tested a possible association between changes in the time spent on or the average intensity of weekly physical activities and changes in cognitive function in healthy men and women. METHODS: This longitudinal cohort study with 1,904 healthy men and women (45-75 years of age) assessed physical activity by a questionnaire and cognitive function with a neuropsychological test battery twice with an interval of 5 years. RESULTS: Multiple linear regression analyses showed that changes in the time spent on physical activities were not associated with changes in cognitive function over a 5-year period. By contrast, changes in average intensity of weekly activities were significantly and positively associated with processing speed (beta = 0.063; p < 0.05). CONCLUSIONS: In this longitudinal cohort study, an increase or smaller decline in average intensity was associated with a smaller age-related decline in processing speed, estimated at 6 years of aging. Ann Epidemiol 2010;20:473-479. (c) 2010 Elsevier Inc. All rights reserved.