A recent study published on 13 May in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association examined how sedentary behaviour relates to longitudinal brain structure and cognitive changes in older adults. Sedentary behaviour is gaining attention as an important modifiable risk factor in aging and recent studies suggest increased sedentary time may also be associated with cognitive decline and Alzheimer's disease (AD). This study examined cross-sectional and longitudinal associations of sedentary time with cognition and structural brain changes using comprehensive neuropsychological testing with 404 participants from the Legacy and Expansion Cohorts of the Vanderbilt Memory and Aging Project (VMAP), a longitudinal observational study of older adults without dementia at study entry. Participants were followed up over a 7-year period, combining actigraphy, neuropsychological assessments and 3T brain MRI scans. Results showed that greater sedentary behaviour was associated with worse neurodegeneration and cognition cross-sectionally and longitudinally despite high levels of physical activity among the cohort. Findings also indicated that cross-sectional associations varied by APOE-ε4 status in several brain regions.
