Multi-discrimination exposure and biological aging: Results from the midlife in the United States study

Discrimination is a social determinant of health and health disparities for which the biological mechanisms remain poorly understood. This study investigated the hypothesis that discrimination contributes to poor health outcomes by accelerating biological processes of aging. We analyzed survey and blood DNA methylation data from the Midlife in the United States (MIDUS) study (N = 1967). We used linear regression analysis to test associations of everyday, major, and workplace discrimination with biological aging measured by the DunedinPACE, PhenoAge, and GrimAge2 epigenetic clocks. MIDUS participants who reported more discrimination tended to exhibit a faster pace of aging and older biological age as compared to peers who reported less discrimination. Effect-sizes for associations tended to be larger for the DunedinPACE pace-of-aging clock (effect-size range r = 0.1–0.2) as compared with the PhenoAge and GrimAge2 biological-age clocks (effect-sizes r < 0.1) and for experiences of everyday and major discrimination as compared with workplace discrimination. Smoking status and body-mass index accounted for roughly half of observed association between discrimination and biological aging. Reports of discrimination were more strongly associated with accelerated biological aging among White as compared with Black participants, although Black participants reported more discrimination overall and tended to exhibit older biological age and faster biological aging. Findings support the hypothesis that experiences of interpersonal discrimination contribute to accelerated biological aging and suggest that structural and individual-level interventions to reduce discrimination and promote adaptive coping have potential to support healthy aging and build health equity.