Assessing differences in epigenetic aging markers between sexual or gender minority and straight cisgender adults using the Coronary Artery Risk Development in Young Adults cohort

Marginalized individuals like sexual and gender minority (SGM) people may experience accelerated biologic aging due to stigma and structural discrimination. We used Coronary Artery Risk Development in Young Adults (CARDIA) cohort data to assess this hypothesis. We first identified SGM individuals using Year 35 sexual orientation and gender identity data, then compared Year 15 (2000-01) or 20 (Y20, 2005-06) epigenetic aging biomarkers between SGM and straight cisgender participants using linear models adjusting for socio-demographics and behavior. Epigenetic markers included intrinsic epigenetic aging acceleration (IEAA), extrinsic EAA, PhenoAge acceleration, and GrimAge acceleration. Our sample (n = 817) was 18.4% SGM. SGM and straight cisgender participants had similar age, sex, and race distributions. Unadjusted and adjusted analyses showed no significant differences between groups except for SGM adults having higher Y20 IEAA in adjusted models compared to straight cisgender adults. Longitudinal models also showed higher rate of change in IEAA in SGM adults. Given the potential of selection bias driving significant results, we used simulations to explore which scenarios can produce observed findings. Our simulations suggest that the observed Y20 IEAA difference is unlikely if there was indeed no disparity. It is also possible that the estimate was an underestimate of the true disparity due to selection from differential survival between the two groups. Our analysis showed no strong evidence of accelerated aging in SGM. Future studies to address limitations are needed.