Socio-economic Inequalities Characterize Molecular Risk for Aging in Young Adulthood.

Diverse manifestations of biological aging often reflect disparities in socioeconomic status (SES). This paper examines associations between indicators of SES and a mRNA-based aging signature during young adulthood, before clinical indications of aging are common. We use data from the National Longitudinal Study of Adolescent to Adult Health, a nationally representative study of adults aged 33-43 with transcriptomic data from a random subset of 2491 participants. Biological aging is measured using a (1) composite transcriptomic aging signature previously identified by Peters et al.'s out-of-sample meta-analysis as well as (2) nine subsets that represent functional pathways of co-expressed genes. SES refers to income, education, occupation, subjective social status, and a composite combining these four dimensions. We examine hypothesized mechanisms through which SES could affect aging: body mass index, smoking, health insurance status, difficulty paying bills, and psychosocial stress. We find that SES-especially the composite and income-is associated with transcriptomic aging and immune, mitochondrial, ribosomal, lysosomal, and proteomal pathways. Counterfactual mediational models suggest that the mediators partially account for these associations. The results thus reveal that numerous biological pathways associated with aging are already linked to SES in young adulthood.