Social disadvantage, genetic sensitivity, and children’s telomere length
This paper makes two contributions to research on the link between the social environment and health.
Using data from a birth cohort study, we show that, among African American boys, those who grow up in highly disadvantaged environments have shorter telomeres (at age 9) than boys who grow up in highly advantaged environments.
We also find that the association between the social environment and telomere length (TL) is moderated by genetic variation within the serotonin and dopamine pathways.
Boys with the highest genetic sensitivity scores had the shortest TL when exposed to disadvantaged environments and the longest TL when exposed to advantaged environments.
To our knowledge, this report is the first to document a gene–social environment interaction for TL, a biomarker of stress exposure.
Disadvantaged social environments are associated with adverse health outcomes. This has been attributed, in part, to chronic stress. Telomere length (TL) has been used as a biomarker of chronic stress:
TL is shorter in adults in a variety of contexts, including disadvantaged social standing and depression. We use data from 40, 9-y-old boys participating in the Fragile Families and Child Wellbeing Study to extend this observation to African American children.
We report that exposure to disadvantaged environments is associated with reduced TL by age 9 y. We document significant associations between low income, low maternal education, unstable family structure, and harsh parenting and TL.
These effects were moderated by genetic variants in serotonergic and dopaminergic pathways. Consistent with the differential susceptibility hypothesis, subjects with the highest genetic sensitivity scores had the shortest TL when exposed to disadvantaged social environments and the longest TL when exposed to advantaged environments.