Neighbourhood socioeconomic disparities in immunohaematologic risk in a paediatric analytic cohort

Growing research on adult development recognises socioeconomically adverse neighbourhood environments as sources of stress affecting immunohaematologic function (IHF), with implications for disease. However, little is known about IHF markers in youth across diverse neighbourhoods. One marker of IHF, red blood cell distribution width (RDW), has demonstrated prognostic value for multiple diseases across the life course.

This retrospective cohort study analysed data from 771 well-child youth ages 5-21 without, and 5,385 sick-child youth with, observable pre-existing immune vulnerability seeking care at a metropolitan healthcare system in the Midwest United States. We employed linear mixed-effects models to examine RDW variation by quintile of neighbourhood socioeconomic position (SEP).

Among well-child youth, the effect of lower neighbourhood SEP diminished (fourth quintile β=0.28, 95 per cent CI [-0.04, 0.60], fifth quintile β=0.16, 95 per cent CI [-0.16, 0.48]) after accounting for youths' racial identity and adjusting for covariates. Among sick-child youth, the effect of lower neighbourhood SEP remained after covariate adjustment (fourth quintile β=0.24, 95 per cent CI [0.08, 0.39], fifth quintile β=0.31, 95 per cent CI [0.16, 0.46]). Across both cohorts, Black racial identity was associated with elevated RDW (well-child cohort β=0.51, 95 per cent CI [0.30, 0.72]; sick-child cohort β=0.65, 95 per cent CI [0.55, 0.74]) after adjusting for neighbourhood SEP, age and biological sex.

Utilising a widely available and low-cost blood test, cellular consequences - as indexed by RDW - of early-life social-environmental adversity may be observable during childhood itself. The vulnerability of youth racialised as Black likely reflects socially produced health inequalities, and study findings evidence a cellular dimension of how structural factors may impact health from a young age.