Abstract
BACKGROUND: The prevalence of allergic respiratory disease (ARD) is increasing worldwide during the last few decades, causing a great disease burden especially for children. Air pollution has been increasingly considered as a potential contributor to this trend, but its role in ARD induced by house dust mite (HDM-ARD) remains unclear, especially in time-series study. METHODS: A positive reporting of respiratory allergy to named allergens was included by serum specific IgE testing. A time series Quasi-Poisson regression with distributed lag non-linear model, combined with generalized linear model was used to examine the effects of air pollutants on ARD, HDM-ARD and ARD induced by non-house dust mite (NHDM-ARD). RESULTS: A total of 16,249 cases of ARD, including 8,719 HDM-ARD and 8,070 NHDM-ARD from 1 Jan 2013 to 31 Dec 2017 were involved in this study. Air pollutants were significantly associated with clinical visits for childhood ARD and HDM-ARD. Exposure to higher O(3) and interquartile range (IQR) increment in O(3) (40.6 µg/m(3)) increased the risks of clinical visits for childhood HDM-ARD (RR(lag0-5) for the 95th percentile of O(3): 1.26, 95% confidence interval (CI): 1.03, 1.55; RR(lag0-5) for IQR increment (40.6 µg/m(3)): 1.09, 95% CI: 1.01, 1.17) and ARD (RR(lag0-5) for the 95th percentile of O(3): 1.19, 95% CI: 1.03, 1.38; RR(lag0-5) for IQR increment (40.6 µg/m(3)): 1.06, 95% CI: 1.01, 1.12). In addition, higher O(3) was associated with increased RR of boys with ARD (RR(lag0-5) for the 95th percentile: 1.26, 95% CI: 1.05, 1.51; RR(lag0-5) for IQR increment (40.6 µg/m(3)): 1.09, 95% CI: 1.02, 1.16) and HDM-ARD (RR(lag0-5) for the 95th percentile: 1.36, 95% CI: 1.06, 1.75; RR(lag0-5) for IQR increment (40.6 µg/m(3)): 1.11, 95% CI: 1.02, 1.22), but not in girls. CONCLUSIONS: Exposure to O(3) appeared to be a trigger of clinical visits for childhood ARD, especially for HDM-ARD and boys. These findings provide novel evidence on the impact of air pollution on HDM-ARD, which may have significant implications for designing effective intervention programs to control and prevent childhood ARD, especially HDM-ARD, in China and other similar developing countries.