Accelerometer Physical Activity is Associated with Greater Gray Matter Volumes in Older Adults Without Dementia or Mild Cognitive Impairment

Objectives: Physical activity (PA) is a modifiable health behavior that can protect against age-related gray matter atrophy and cognitive dysfunction. Current studies of PA and gray matter failed to utilize device measures of PA and do not focus on adults >80 years. Thus, the purpose of this secondary analysis was to examine cross-sectional associations between accelerometer lifestyle PA and (a) gray matter volumes and (b) cognitive function, controlling for demographics, and health status. Method: Participants were 262 older adults without dementia or mild cognitive impairment from Rush Memory and Aging Project, an epidemiological cohort study. Participants wore an accelerometer to assess total daily lifestyle PA, and completed anatomical magnetic resonance imaging to assess gray matter volumes and a neurocognitive test battery to assess cognitive function. Results: Multivariate linear regression indicated that higher levels of total daily lifestyle PA was significantly related to larger gray matter volumes, F(2, 215) = 3.61, p =.027, including subcortical gray matter (beta = 0.17, p = .007) and total gray matter (beta = 0.11, p = .049), with no significant associations between lifestyle PA and cognitive function. Discussion: These findings may inform future lifestyle PA interventions in order to attenuate age-related gray matter atrophy.