Medium-to-High Late-Life Physical Activity Is Associated with Lower Risk of Incident Dementia: The Shanghai Aging Study.

Abstract

There is significant evidence that physical activity has profound effects on the neurochemistry and plasticity of the brain and may prevent cognitive decline. This study aimed to determine the association between physical activity and incident dementia among older Chinese adults. In the prospective phase of the Shanghai Aging Study, 1,648 community-dwellers aged 60 years or older were followed for an average of 5 years. Their physical activity was assessed based on questionnaires. The physical activities were further transformed into metabolic equivalent values. A consensus diagnosis of incident dementia was ascertained based on medical, neurological, and neuropsychological data and the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition. We identified 166 incident dementia cases; the incidence rate was 19.4 per 1000 person-years. A multivariate Cox regression model indicated that compared to low levels of physical activity, medium-to-high levels of physical activity were associated with a reduced risk of dementia (hazard ratio, 95% confidence interval = 0.62, 0.44-0.89) after adjusting for age, sex, years of education, apolipoprotein E ɛ4, and other confounders. Our findings demonstrate that medium-to-high level of physical activity is protective against dementia in older adults.