Dose‐response relationship between late‐life physical activity and incident dementia: A pooled analysis of 10 cohort studies of memory in an international consortium
Wanqing Wu, Ding Ding, Qianhua Zhao, Zhenxu Xiao, Jianfeng Luo, Mary Ganguli, Tiffany F. Hughes, Erin Jacobsen, Mary N. Haan, Kristine van Dang, Maria Fernanda Lima‐Costa, Sérgio Luís Blay, Erico de Castro‐Costa, Tze Pin Ng, Xinyi Gwee, Qi Gao, Oye Gureje, Akin Ojagbemi, Toyin Bello, Suzana Shahar, Arimi Fitri Mat Ludin, Nurul Fatin Malek Rivan, Nikolaos Scarmeas, Costas A. Anastasiou, Mary Yannakoulia, Henry Brodaty, John D. Crawford, Richard B. Lipton, Carol A. Derby, Mindy J. Katz, Darren M. Lipnicki, Perminder S. Sachdev
Abstract
INTRODUCTION: Though consistent evidence suggests that physical activity may delay dementia onset, the duration and amount of activity required remains unclear. METHODS: We harmonized longitudinal data of 11,988 participants from 10 cohorts in eight countries to examine the dose-response relationship between late-life physical activity and incident dementia among older adults. RESULTS: Using no physical activity as a reference, dementia risk decreased with duration of physical activity up to 3.1 to 6.0 hours/week (hazard ratio [HR] 0.88, 95% confidence interval [CI] 0.67 to 1.15 for 0.1 to 3.0 hours/week; HR 0.68, 95% CI 0.52 to 0.89 for 3.1 to 6.0 hours/week), but plateaued with higher duration. For the amount of physical activity, a similar pattern of dose-response curve was observed, with an inflection point of 9.1 to 18.0 metabolic equivalent value (MET)-hours/week (HR 0.92, 95% CI 0.70 to 1.22 for 0.1 to 9.0 MET-hours/week; HR 0.70, 95% CI 0.53 to 0.93 for 9.1 to 18.0 MET-hours/week). DISCUSSION: This cross-national analysis suggests that performing 3.1 to 6.0 hours of physical activity and expending 9.1 to 18.0/MET-hours of energy per week may reduce dementia risk.