Background: Psychosocial factors are modifiable risk factors for Alzheimer's disease (AD). One mechanism linking psychosocial factors to AD risk may be through biological measures of brain amyloid; however, this association has not been widely studied.
Objective: To determine if mid-life measures of social support and social isolation in the Atherosclerosis Risk in Communities (ARIC) Study cohort are associated with late life brain amyloid burden, measured using florbetapir positron emission tomography (PET).
Methods: Measures of social support and social isolation were assessed in ARIC participants (visit 2: 1990-1992). Brain amyloid was evaluated with florbetapir PET standardized uptake value ratios (SUVRs; visit 5: 2012-2014).
Results: Among 316 participants without dementia, participants with intermediate (odds ratio (OR), 0.47; 95% CI, 0.25-0.88), or low social support (OR, 0.43; 95% CI, 0.22-0.83) in mid-life were less likely to have elevated amyloid SUVRs, relative to participants with high social support. Participants with moderate risk for social isolation in mid-life (OR, 0.32; 95% CI, 0.14-0.74) were less likely to have elevated amyloid burden than participants at low risk for social isolation. These associations were not significantly modified by sex or race.
Conclusions: Lower social support and moderate risk of social isolation in mid-life were associated with lower odds of elevated amyloid SUVR in late life, compared to participants with greater mid-life psychosocial measures. Future longitudinal studies evaluating mid-life psychosocial factors, in relation to brain amyloid as well as other health outcomes, will strengthen our understanding of the role of these factors throughout the lifetime.
Keywords: Alzheimer’s disease; amyloid-beta; dementia; mid-life; positron emission tomography; psychosocial factors.