Current and past leisure time physical activity in relation to risk of Alzheimer's disease in older adults

INTRODUCTION: The associations between self-reported current and past leisure time physical activity (LTPA) and Alzheimer's disease (AD) incidence were determined using data from the multiethnic Washington/Hamilton Heights-Inwood Columbia Aging Project (WHICAP) study. METHODS: The metabolic equivalent of LTPA energy expenditure was calculated for self-reported current and past LTPA for 1345 older adults. A Cox proportional hazard model was conducted to estimate the association between LTPA (low, middle, and high) and incident AD risk. RESULTS: Comparing high to low level, current and past LTPA were both associated with reduced AD risk, with hazard ratio (95% confidence interval) = 0.39 (0.20-0.75) and 0.37 (0.18-0.75), respectively. Compared with "always low," "increased" and "always high" LTPA throughout life were associated with reduced AD risk, with hazard ratio (95% confidence interval) = 0.60 (0.36-0.99) and 0.28 (0.08-0.94), respectively. Light- and moderate-intensity LTPA were associated with lower AD risk. DISCUSSION: LTPA both throughout life and later in life are associated with lower risk of AD.