Life course socioeconomic disadvantage and persistent infection burden: Links to cellular immunosenescence in U.S. young adults.

BACKGROUND

Socioeconomic status (SES) disadvantage shapes exposure to persistent infections and immune aging, but its life-course effects remain understudied. Early adulthood is a crucial period, as immune aging may begin before clinical signs appear.

METHODS

Data from the National Longitudinal Study of Adolescent to Adult Health (Add Health) were used to assess SES disadvantage across adolescence (Wave I) and young adulthood (Wave IV). Four life-course SES disadvantage trajectories were defined: non-disadvantaged, upward mobility, downward mobility, and persistent disadvantage. Outcomes included dried blood spot-based seropositivity and IgG antibody levels for Cytomegalovirus (CMV), Herpes simplex virus type 1 (HSV-1), Epstein-Barr virus (EBV), and Helicobacter pylori (H. Pylori) in young adulthood, and DNA-methylation-based CD4+ and CD8+ memory/naïve and CD4+/CD8+ ratios in early midlife (Wave V). Multivariable regression models evaluated associations between SES trajectories and outcomes.

RESULTS

In young adulthood, persistent SES disadvantage was associated with higher odds of CMV, HSV-1, and H. Pylori infection (e.g. H. Pylori OR = 2.2, 95 % CI: 1.7, 2.9) and higher antibody levels (e.g. HSV-1 β = 1.4, 95 % CI: 0.9, 1.9). In early midlife, it was associated with CMV seropositivity and antibody levels (OR = 1.8, 95 % CI: 1.4-2.3; β = 13.0, 95 % CI: 7.4, 18.7), and elevated CD4+ and CD8+ memory/naïve ratios (e.g. CD4+ β = 0.3, 95 % CI: 0.1, 0.5). Associations with upward and downward mobility were weaker and less consistent across outcomes.

CONCLUSIONS

Persistent SES disadvantage was consistently associated with higher infection burden and more aged immune cell profiles before midlife. Understanding this link is key for addressing health disparities.