Is social connection the key to prevention? Educational attainment, incident dementia, and the role of later-life social engagement.

Background and Objectives: Educational attainment and mid-to-later-life social engagement are modifiable risk factors for dementia, yet limited research examines how these factors intersect to shape dementia risk. This study estimates the extent to which social engagement may act as a pathway through which education influences incident dementia, and which forms of social engagement may most reduce educational differences in incident dementia among older adults in the United States. Research Design and Methods: We used survival and counterfactual decomposition analyses of the 2011-2018 National Health and Aging Trends Study to assess whether, and to what extent, different forms of social engagement mediate and interact with the effect of educational attainment on incident dementia. We compared total and controlled direct effects to assess how educational differences in incident dementia may shift under hypothetical scenarios of having large discussion networks and prior-month engagement in social activities among older adults with higher and lower levels of education. Results: Going out for enjoyment, visiting with friends/family, volunteering, and organized group activities were significant partial mediating pathways in the association between education and incident dementia. When prior-month volunteering, organized group activity attendance, and a large network size were modeled as mediators, educational differences in incident dementia were attenuated and became statistically nonsignificant. Discussion and Implications: Findings suggest increasing older adults' participation in volunteering and group activities, as well as larger discussion networks, may reduce educational disparities in dementia risk. Future research should investigate the mechanisms driving these results and whether they extend to other social activities not examined in this study.