Discrepancies in loneliness and social isolation predict cognitive impairment through chronic disease burden

The discrepancy between loneliness and objective social isolation (social asymmetry) has been linked to poorer cognitive aging, yet the biobehavioral pathways underlying this association remain unclear. This study tested whether chronic disease burden or allostatic load mediated associations between social asymmetry and subsequent cognitive performance. We analyzed data from 840 adults (mean age = 54 years, range = 34–81 years) from the Midlife in the United States (MIDUS) Biomarker Project using structural equation modeling to test parallel mediation through allostatic load and chronic disease burden. Social asymmetry was associated with greater chronic disease burden but showed minimal association with allostatic load. Chronic disease burden significantly mediated relationships between social asymmetry and episodic memory and executive function, whereas allostatic load did not. Conclusions : Chronic disease burden showed stronger statistical evidence as an indirect pathway linking social asymmetry to subsequent cognitive outcomes than the allostatic load composite. These findings suggest that disease prevention may be an important target for preserving cognition in socially vulnerable adults. • In a national sample of adults (MIDUS), loneliness exceeding one’s level of social contact predicted poorer memory and executive function. • Chronic morbidity, not stress physiology, mediates social vulnerability effects on cognition. • Findings underscore disease prevention and management to protect cognitive health.