Exposure to air pollution and incidence of atopic dermatitis in the general population: A national population-based retrospective cohort study

Abstract

Background: To date, little evidence is available to determine whether atopic dermatitis (AD) can be caused by exposure to air pollutants, including gases and particulate matter. Objective: We aimed to evaluate the relationship between air pollutants and incidence of AD using the National Health Insurance Service-National Sample Cohort database. Methods: We included 209,168 subjects from the general population previously not diagnosed with AD between 2008 and 2013. Long-term average concentration of air pollutants before diagnosis was calculated for each subject. Results: For 1,030,324 person-years, incident cases of AD were observed in 3203 subjects. There was a significant positive association between incidence of AD and long-term average concentration of particulate matter smaller than 2.5 μm in diameter (hazard ratio [HR], 1.420; 95% CI, 1.392-1.448; for 1 μg/m3), particulate matter smaller than 10 μm in diameter (HR, 1.333, 95% CI, 1.325-1.341; for 1 μg/m3), sulfur dioxide (HR, 1.626; 95% CI, 1.559-1.695; for 1 parts per billion), nitrogen dioxide (HR, 1.200; 95% CI, 1.187-1.212; for 1 parts per billion), and carbon monoxide (HR, 1.005; 95% CI, 1.004-1.005; for 1 parts per billion) after adjusting for age, sex, income, comorbid diseases, and meteorologic variables. Limitations: The National Health Insurance Service database lacks detailed information on individual subjects. Conclusions: This study demonstrated that long-term exposure to air pollutants, including gases and particulate matter, is an independent risk factor for developing AD.