The Impact of Air Pollution Exposure in Early Childhood on the Prevalence of Atopic Dermatitis in Preschool-Aged Children

Abstract

Atopic dermatitis (AD) is a common inflammatory skin condition in children influenced by genetic and environmental factors, potentially including air pollution. While research has linked air pollution to the development of allergic diseases, such as asthma, few studies have examined AD, and none of these have been based in the United States. Understanding the role of early-life air pollution exposure in AD development could inform biological mechanisms and prevention strategies. This study evaluated associations between early-life exposure to ozone (O3), nitrogen dioxide (NO2), and fine particulate matter (PM2.5) and AD status at ages 4-6 years and explored whether associations differed by child sex. We conducted a prospective cohort study using data from 2,023 children in the ECHO PATHWAYS Consortium. Three AD outcomes were defined using caregiver report on the ISAAC (International Study of Asthma and Allergies in Childhood) questionnaire, and pollutant exposure at children’s residential address during the first year was estimated using validated spatiotemporal models. Multivariable logistic regression models were used to examine associations between each pollutant and outcome, while adjusting for confounders. AD prevalence was 13-32%, with higher prevalence among non-Hispanic Black children. O3 exposure during the first year of life was positively associated with current AD (aOR per 1-ppb increase = 1.08; 95% CI: 1.00, 1.17). No associations were observed for NO2 or PM2.5 exposure. Some evidence suggested sex-specific associations of NO2, with higher NO2 exposure associated with lower risk of AD in boys only, but the biological plausibility for protective effects is low. We conclude that early-life O3 exposure may increase AD risk in early childhood, supporting O3 as a potential modifiable environmental risk factor. Further studies on pollutant mixtures and biological mechanisms are needed.