Socially stratified DNA-methylation profiles are associated with disparities in child and adolescent mental health

Importance: Economic and racial inequality is linked to disparities in children9s mental health. Biomarkers that reflect these social disparities are lacking. Objective: We examined the hypothesis that salivary DNA-methylation patterns of higher inflammation and faster pace of biological aging are economically, racially and ethnically stratified and are associated with child mental health. Design: The Texas Twin Project is an on-going, observational, longitudinal study that began in May 2012. Analyses were preregistered on May 7, 2021, and completed on August 23, 2021. Setting: The population-based study identified and recruited participants from public school rosters in the greater Austin area. Participants: Participants in the analytic data set included all participants that agreed to contribute DNA samples and whose samples were assayed by January 2021. Exposures: Family- and neighborhood-level socioeconomic inequality, racial and ethnic identities (White, Latinx, Black, Asian). Main Measure(s): Environmental exposures were analyzed in relation to salivary DNA-methylation profiles of higher inflammation (DNAm-CRP) and faster pace of biological aging (DunedinPoAm). Child internalizing problems, attention problems, aggression, rule-breaking, ADHD, oppositional defiant disorder, and conduct disorder were measured using parent-reports and self-reports on abbreviated versions of the Achenbach Child Behavior Checklist and Conners 3. The hypotheses being tested were formulated after data collection of the present data freeze and were pre-registered prior to analyses being conducted. Results: In a sample of N=1,183 8-to-19-year-olds (609 female, age M=13.38y), children9s salivary DNA-methylation profiles and psychiatric symptoms differed by socioeconomic conditions, race and ethnicity. Children with more parent-reported internalizing symptoms had higher DNAm-CRP (r=0.15, 95% CI=0.05 to 0.25, P=0.004) and DunedinPoAm (r=0.15, CI=0.05 to 0.25, P=0.002), and children with more parent-reported aggression problems had higher DNAm-CRP (r=0.17, CI=0.04 to 0.31, P=0.013). DNAm-CRP partially mediated advantage of higher family socioeconomic status (16% of total effect) and White racial identity (12% of total effect) on reduced internalizing symptoms. DunedinPoAm also partially mediated advantage of White racial identity on internalizing (19% of total effect). Conclusions and Relevance: Socioeconomic and racial inequality are visible in children9s epigenetic profiles of inflammation and the rate of biological aging in a manner that is tied to social disparities in mental health.