The Long Half-Life of Neighborhood Poverty: Duration, Timing, and Biological Aging

Point-in-time measures of neighborhood poverty exposure suggest a link with physiological aging, but it remains unclear how histories and the timing of residential disadvantage connect to weathering. In this issue, D'Alessio et al. (Am J of Epidemiol. 2026) use 25 years of prospective residential data from the National Longitudinal Study of Adolescent to Adult Health (Add Health) to link neighborhood poverty across adolescence, early adulthood, and early midlife to three epigenetic clocks. They identify selective dose-response relationships. Each additional life stage in a high-poverty tract is associated with accelerated biological aging, and exposure is distributed with sharp racial inequality. The per-stage effect is modest in individual terms but consequential at population scale. Its unequal allocation makes residential segregation a plausible epigenetic mechanism of population-level racial disparities in aging. We argue that-despite its considerable strengths-the study leaves two questions unresolved. First, does health-selective residential mobility drive part of the association? Second, does the prominence of mid-life exposure reflect a true sensitive period, or the fact that mid-life poverty is measured in close proximity to biospecimen collection? We outline potential follow-up work that could address these questions via structured life course methods and better-powered cohorts with tract-linked data, including Add Health.