The prenatal and postnatal effects of air pollution on asthma in children with atopic dermatitis

Objectives: Air pollution is strongly associated with asthma, but has not been determined to induce new-onset asthma development in children with atopic dermatitis (AD). Working Hypothesis: To assess whether prenatal/postnatal exposure to air pollutants triggers new-onset asthma development in children with AD. Study Design: Retrospective cohort study. Patient-subject Selection: Data of patients <age 18 years diagnosed with eczema or AD between 2009 and 2019 were extracted from the multicenter Kaohsiung Medical University Hospital Research Database. Patients diagnosed with new-onset asthma were in the asthma group and patients without asthma history were in the non-asthma group. Methodology: The monthly average concentration of air pollutants for 1, 3, and 5 years before the index date, and 3, 6, and 9 months prenatally were analyzed and further stratified by age, immunoglobulin (Ig) E, and the percentage of eosinophil and eosinophil cationic protein (ECP). Results: Postnatal exposure to airborne particulate matter (PM_2.5, PM₁₀), sulfur dioxide (SO₂), ozone (O₃), carbon monoxide (CO), nitric oxide (NO), nitric dioxide (NO₂), and NO_x, and prenatal exposure to PM_2.5, PM₁₀, SO₂, NO, and NO_x were significantly higher in the asthma group than in the non-asthma group. Patients having IgE above 100 IU/ml and ECP less than 24 ng/ml were significantly influenced by postnatal exposure to PM_2.5 and PM₁₀, especially CO, to develop asthma, and those having an eosinophil count >3% were significantly influenced by prenatal exposure to PM_2.5, especially SO₂, NO, and NO₂. Conclusions: Prenatal and postnatal exposure to air pollution have an association with asthma development in AD patients.