The associations between sedentary behavior and cognition in a population cohort of older adults.

BackgroundSedentary behavior is common in older adulthood and is associated with poor health outcomes. Less is known about how sedentary behavior relates to cognition in older adulthood and how it relates to increased risk for cognitive decline associated with Alzheimer's disease (AD).ObjectiveWe sought to examine these associations in a large, population-based cohort of community-dwelling older adults residing in a Rust Belt region of the United States.MethodsA subset of the population-based Monongahela-Youghiogheny Healthy Aging Team (MYHAT) participants (n = 193) completed 7 days of wrist-accelerometry following comprehensive neuropsychological assessment. Cross-sectional linear regression models related sedentary time to domains of cognition. Models were adjusted by age, sex, education, and APOE4 carrier status and moderate to vigorous physical activity (MVPA). The interaction between sedentary behavior and APOE4 genotype on cognition was also examined.ResultsGreater sedentary behavior was associated with worse executive function (β = -0.06, p = 0.01) and memory (β = -0.06, p = 0.05) performance. These results were attenuated when adjusting for MVPA. No significant interactions between sedentary time and APOE4 carrier status were observed, although estimation results applying the delta method on regression coefficients suggested the associations were stronger in APOE4 non-carriers when compared to APOE4 carriers.ConclusionsHigher levels of sedentary behavior were associated with worse performance in cognitive domains implicated in AD. Public health initiatives and precision-based medicine approaches to reduce sedentary behavior in a population-based cohort of older adults may be important AD prevention measures. Results support the importance of reducing sedentary time.