Physical activity and alzheimer's disease course

Objectives: To examine the association between physical activity (PA) and Alzheimer’s disease (AD) course. Background: PA has been related to lower risk for AD. Whether PA is associated with subsequent AD course has not been investigated. Methods: In a population-based study of individuals older than 65 in New York who were prospectively followed with standard neurological and neuropsychological evaluations (every ~1.5 years), 357 participants (i) were non-demented at baseline and (ii) were diagnosed with AD during follow-up (incident AD). PA (sum of participation in a variety of physical activities, weighted by the type of activity [light, moderate, severe]) obtained 2.4 (sd. 1.9) years before incidence was the main predictor of mortality in Cox models and of cognitive decline in GEE models that were adjusted for age, gender, ethnicity, education, comorbidities and duration between PA evaluation and dementia onset. Results: 150 incident AD cases (54%) died during the course of 5.2 (sd 4.4) years of follow-up. As compared to incident AD cases who were physically inactive, those with some PA had lower mortality risk, while incident AD participants with much PA had an even lower risk. Additional adjustments for APOE genotype, smoking, comorbidity index and cognitive performance did not change the associations. PA did not affect rates of cognitive or functional decline. Conclusion: Exercise may affect not only risk for AD but also subsequent disease duration: more PA is associated with prolonged survival in AD.