Modification of allergic dermatitis on the associations between early-life exposure to size-specific particulate matter and childhood allergic rhinitis

Objective To evaluate the modification of allergic dermatitis on the association between PM exposure and allergic rhinitis in preschool children.Methods We adopted a cross-sectional study and conducted a questionnaire survey among preschool children aged 3 to 6 years in 7 cities in China from June 2019 to June 2020 to collect information on allergic rhinitis and allergic dermatitis. A mature machine learning-based space-time extremely randomized trees model was applied to estimate early-life, prenatal, and first-year exposure of PM1, PM2.5 and PM10 at 1 × 1-km resolution. We used a combination of multilevel logistic regression and restricted cubic spline functions to quantitatively assess whether allergic dermatitis modifies the associations between size-specific PM exposure and the risk of childhood allergic rhinitis.Results The adjusted ORs for childhood allergic rhinitis among the children with allergic dermatitis as per interquartile range (IQR) increase in early-life PM1(9.8 μg/m3), PM2.5 (14.9 μg/m3) and PM10 (37.7 μg/m3) were significantly higher than the corresponding ORs among the children without allergic dermatitis [OR: 1.45, 95% CI (1.26, 1.66) vs. 1.33, 95% CI (1.20, 1.47), for PM1; OR: 1.38, 95% CI (1.23, 1.56) vs. 1.32, 95% CI (1.21, 1.45), for PM2.5; OR: 1.56, 95% CI (1.31, 1.86) vs. 1.46, 95% CI (1.28, 1.67), for PM10]. The interactions between allergic dermatitis and size-specific PM exposure on childhood allergic rhinitis were statistically significant (all p-int < 0.001). The similar patterns were observed for both prenatal and first-year size-specific PM exposure and the results of the dose-response relationship were consistent with those of the logistic regression.Conclusions Allergic dermatitis, as an important part of the allergic disease progression, may modify the association between ambient PM exposure and the risk of childhood allergic rhinitis. Children with allergic dermatitis should pay more attention to minimize outdoor air pollutants exposure to prevent the further progression of allergic diseases.