Air pollution and emergency department visits for urticaria

Abstract

BACKGROUND AND AIM: The objective of this work was to investigate correlations between air pollution and emergency department (ED) visits for urticaria in Toronto, Canada. METHODS: The National Ambulatory Care Reporting System database was used to draw the diagnosed ED visits. The L50 section of the International Classification of Disease 10th Revision was used to extract ED visits whose primary causes of visit was urticaria-related conditions. Statistical models (Poisson regression) using daily counts of ED visits were created for urticaria, ambient air pollution concentrations, and weather factors. We considered two air quality health indexes and six ambient air pollutants for exposure: fine particulate matter PM2.5, O3, CO, NO2, SO2, and maximum 8-hour average ozone. RESULTS:A total of 176 statistically significant (P-Value 0.05) positive correlations were identified over the 14 day lag period. For ozone,74 positive correlations were observed with the following relative risks (RR) for one interquartile range (IQR=12.8 ppb) increase: RR=1.361 (95% confidence interval: 1.302, 1.404), 1.359 (1.299, 1.401), 1.351 (1.281, 1.404) in the warm season (April-September), lag 0, and RR=1.019 (1.013, 1.025), 1.023 (1.016, 1.030), 1.014 (1.007, 1.021), lag 1, in the cold period (October-March), for all, females, and males, respectively. 10, 45 and 45 positive correlations were also obtained for sulfur dioxide, fine particulate matter, and daily maximum 8-hour average ozone concentrations, respectively. CONCLUSIONS:The results indicate that urban ambient air pollution could influence the rates of ED visits for urticaria. Ambient ozone was determined as the main environmental factor contributing to these associations. KEYWORDS: Ozone, Traffic-related, Short-term exposure, Allergies