The contribution of social and economic factors to accelerated biological aging differences between non-Hispanic Black and White adults in the Health and Retirement Study.

<h4>Background</h4>Biological aging predicts health outcomes beyond chronological age. The relative contribution of social, economic, and health factors to biological aging differences between Black and White adults remains unclear.<h4>Methods</h4>In a cross-sectional analysis of 2086 community-dwelling adults aged ≥60 years from the 2016 Health and Retirement Study (1757 non-Hispanic White; 329 non-Hispanic Black), biological age was measured using DNA methylation-based GrimAge. Accelerated aging was defined as having a biological age older than expected for one's chronological age. We used logistic regression to assess the impact of race on accelerated aging and decomposition analysis to determine factors explaining differences in accelerated aging between Black and White participants. Covariate blocks were: age, education, wealth, social frailty assessed using a composite index measuring social connections, financial autonomy, neighborhood environment, volunteering and employment engagement, behavioral factors (physical activity, alcohol use, sleep disorder, body mass index); medical conditions; and physical disability.<h4>Results</h4>Black participants had higher accelerated aging than White participants (57.1% vs 41.8%; standardized mean difference, 0.3). In the staged decomposition of the biological aging gap, age and education explained 21.1% of the difference. The cumulative explained share rose to 51.8% with wealth, 77.6% with social frailty, 80.3% with health behaviors, 90.5% with medical conditions, and 91.6% with physical disability. In multivariable logistic regression adjusting for all domains, the racial difference was no longer significant.<h4>Conclusions</h4>Social and economic factors largely explained accelerated biological aging differences between non-Hispanic Black and White adults. These findings identify policy-relevant targets to improve healthy aging.