Sleep and participation in extracurricular activities moderate associations between low SES and brain structure and functional connectivity.

Household and neighborhood socioeconomic status (SES) have consistently been associated with both brain structure and functional connectivity in adolescence. However, there is considerable heterogeneity in brain outcomes among youth from disadvantaged backgrounds, which suggests that other factors-including aspects of one's lifestyle-likely play a role by moderating these associations. In a large sample of ~10,000 early adolescents from the baseline assessment of the Adolescent Brain Cognitive Development study (aged 9-10 years), we tested whether sleep and participation in physical and non-physical extracurricular activities moderate associations of household and neighborhood disadvantage with brain structure and functional connectivity. Higher sleep duration was linked to weaker associations between both household and neighborhood disadvantage and a range of structural and functional brain measures, whereas extracurricular engagement had more selective moderating effects on the structure of sensory regions. Our findings identify sleep duration and extracurricular engagement as markers of variability in SES-brain associations, underscoring the need for longitudinal and intervention studies to determine whether these factors can mitigate disparities in brain outcomes among youth from disadvantaged backgrounds.