Associations between mid-life social relationships and the risk of incident dementia: The ARIC study

INTRODUCTION: This study aimed to assess whether mid-life social relationships are associated with a lower risk of late-life dementia. METHODS: Participants in the Atherosclerosis Risk in Communities (ARIC) study were assessed for social support and isolation (Visit 2;1990-1992). A composite measure, "social relationships," was generated. Incident dementia cases were identified following Visit 2 through 2019, using ongoing surveillance. Associations between mid-life social relationships and incident dementia were evaluated with Cox proportional-hazard regression models. Formal interaction tests examined whether sex or race modified this association. RESULTS: Among 13,070 participants without dementia, those with strong social relationships in mid-life had a lower risk for developing dementia, compared to participants with poor mid-life social relationships. Neither sex nor race significantly modified this association. DISCUSSION: Stronger mid-life social relationships may have a potentially protective effect on dementia risk. Future studies evaluating psychosocial health at multiple time points in ethnically diverse populations are needed. HIGHLIGHTS: Psychosocial health is a modifiable risk factor for dementia. Stronger mid-life social relationships are associated with a lower risk of dementia. Social relationships may have a potentially protective effect on late-life outcomes. This study leveraged data collected from nearly 20 years of follow-up in 13,070 participants. Longitudinal data used in this study were captured in a population that is 24% Black.