The interactive effects between air pollution and meteorological factors on the hospital outpatient visits for atopic dermatitis in Beijing, China: a time-series analysis

Background The prevalence of atopic dermatitis (AD) dramatically increased over these years and environmental factors were considered as potential contributors towards these trends. Objective This study aimed to explore several major environmental exposures, including air pollution, temperature and relative humidity, in order to identify potential modifiable risk factors and their interactive effects on AD. Methods We applied a bivariate response surface model and stratification model based on time-series Poisson generalized additive models to examine the interactive effects of air pollution and meteorological factors on AD. Results A total of 64 987 outpatient visits for AD were recorded from 1 January 2013 to 31 December 2017. Interactive effects were found between air pollutants and meteorological factors. Enhanced positive associations between pollutants and outpatient visits for AD were found at the highest quartile temperature level. A 10 mu g/m(3) increase in PM2.5, PM10, NO2 and SO2 were associated with 0.42% (95% CI: 0.16-0.67%), 0.34% (95% CI: 0.15-0.54%), 1.11% (95% CI: 0.38-1.84%) and 1.06% (0.21-1.93%) increase in outpatient visits for AD at the highest quartile temperature level. Conclusion That effects of air pollutants on AD can be modified by meteorological factors, with enhanced effects on hot days.