Social engagement, amyloid burden, and dementia: the Atherosclerosis Risk in Communities (ARIC) - PET study

Authors

• RC Greochel
• AC Liu
• C Liu
• SD Knopman
• S Koton
• AM Kucharaka-Newton
• PL Lustey
• TH Mosley Jr
• P Palta
• AR Sharrett
• KA Walker
• DF Wong
• RF Gottesman

Abstract

Background: Although amyloid deposition in the brain is often associated with subsequent dementia risk, not everyone with brain amyloid will develop dementia. This discrepancy illustrates the potential importance that vascular and lifestyle risk factors may have in modifying this association. Compared to participants with low mid-life social engagement, we hypothesized that participants with high mid-life social engagement will show a weaker association between amyloid burden and incident dementia.

Method: Participants in the Atherosclerosis Risk in Communities (ARIC) Study were assessed for social support and social isolation (visit 2; 1990-1992). Through these measures, a composite measure, “social engagement” was generated. Brain amyloid was evaluated with florbetapir PET (visit 5; 2012-2014). Incident dementia cases were identified following visit 5 through December 31, 2019 using ongoing surveillance. Relative contributions of mid-life social engagement and elevated brain amyloid to incident dementia, independently and with multiplicative interaction terms, were evaluated with Cox regression models. Models were adjusted for demographics, APOE4, and vascular risk factors.

Result: Among 310 participants, 48 developed dementia (median follow-up: 4.7 years). Greater mid-life social engagement was independently associated with lower dementia risk. Elevated late life brain amyloid was associated with greater dementia risk.

Conclusion: We found no evidence that mid-life social engagement reduces the risk of dementia in participants with elevated brain amyloid burden in late life. Future longitudinal studies evaluating the potential influence of social factors measured throughout the life course are needed to inform our understanding as to what factors may preserve cognition in the presence of brain pathology.

Scientific Focus Area: Epidemiology

This page was last updated on Monday, September 25, 2023