Associations of ambient air pollution and daily outpatient visits for pediatric atopic dermatitis in Shanghai, China.

Limited evidence was available on ambient air pollution and pediatric atopic dermatitis (AD). The study aimed to evaluate the associations between short-term exposure to air pollutants and outpatient visits for pediatric AD. From 2016-2018, we collected data on six criteria air pollutants (PM, PM, NO, SO, CO and O) and daily outpatient visits for pediatric AD in 66 hospitals, covering all districts in Shanghai, China. The over-dispersed Poisson generalized additive model (GAM) was applied to fit the associations of criteria air pollutants with hospital visits. Two-pollutant models were fitted and stratified analyses by sex, age and season were conducted. We identified 477,833 outpatient visits for pediatric AD. Each interquartile range (IQR) increase in PM (IQR: 30.9 μg/m), PM (8.9 μg/m), NO (25.5 μg/m), SO (5.8 μg/m) and CO (0.283 mg/m) on the concurrent day was significantly associated with increments of 2.08 % (95 % CI: 0.53 %, 3.65 %), 2.53 % (95 % CI: 0.87 %, 4.22 %), 8.14 % (95 % CI: 6.24 %, 10.08 %), 5.67 % (95 % CI: 3.58 %, 7.80 %), and 2.27 % (95 % CI: 0.70 %, 3.87 %) in pediatric AD outpatient visits, respectively. The effects of NO remained robust after adjustment for other air pollutants. The exposure-response curves for PM and PM were steeper for moderate-lower concentrations, with a flatten curves at high concentration; nearly linear relationships were found for NO. Higher associations of NO exposure on AD were detected in children under 6 years old (p=0.01); and we observed larger effect of air pollutants in cool seasons (p<0.001 for PM, PM, NO and CO; p=0.043 for SO). This study indicated that short-term exposure to air pollution could increase risk of outpatient visits for pediatric AD.