A prospective examination of the relationship between physical activity and dementia risk in later life.

PURPOSE: To examine the relationship between vigorous physical activity and dementia risk.

DESIGN: Prospective study design utilizing physical activity data from the Health and Retirement Study and cognitive outcome data from the Aging, Demographics, and Memory Study.

SETTING: Community-based.

SUBJECTS: Adults age 71 and over (N  =  808) with 3 to 7 years of physical activity information prior to dementia/no dementia diagnosis.

MEASURES: Physical activity was measured by participation in vigorous activities such as aerobics, sports, running, bicycling, and heavy housework three or more times per week (yes/no). Dementia diagnosis was based on an expert panel (e.g., neuropsychologists, neurologists, geropsychiatrists) who performed and reviewed a battery of neuropsychological tests.

ANALYSIS: Binary logistic regression models were used to account for demographic characteristics, genetic risk factors (one or two apolipoprotein E ε4 alleles), health behaviors (e.g., smoking, drinking alcohol), health indicators (body mass index), and health conditions (e.g., diabetes, heart disease) in a sequential model-building process.

RESULTS: The relationship between vigorous physical activity and dementia risk remained robust across models. In the final model, older adults who were physically active were 21% (p ≤ .05) less likely than their counterparts to be diagnosed with dementia.

CONCLUSION: Vigorous physical activity may reduce the risk for dementia independently of the factors examined here. This study's findings are important given that few preventative strategies for dementia have been explored beyond hormonal therapy and anti-inflammatory drugs.