Ambient air pollution and emergency department visits for skin conditions

Studies have reported associations between ambient air pollution exposure and occurrence of various skin diseases. In addition, a few epidemiological studies also indicated associations of air pollution exposure with cellulitis. The purpose of this multi-city study was to examine potential associations between emergency department (ED) visits for skin conditions and ambient air pollution concentrations. The study was conducted using the data for the period from April 2004 to December 2011 in nine cities across the province of Ontario, Canada. ED visits for skin conditions were retrieved from the National Ambulatory Care Reporting System using the International Classification of Diseases, ICD-10 codes: R20, R21, and for cellulitis L03, L25.9, and L50.9. For this study, a case-crossover design was applied. Conditional logistic regression was used to realize statistical models. Temperature and humidity in the form of natural splines were used as cofounders. Odds ratios and their 95% confidence interval have been calculated for one unit increases in the interquartile values of considered air pollutants. For cellulitis (N=252,799), significant positive results were observed for O3 for lags 1, 4 and 5 days among females. For males, statistically significant positive results were observed for PM2.5 for lags 3 to 6. For other skin conditions (N=201,571), significant positive results were also observed in females for PM2.5, for lags 2 to 8 days; for O3 , for lags 0 to 2 days; and, for NO2 and SO2 , for lags 6 to 8 days. For males, PM2.5 remained positive among all lags, and was statistically significant for lags 4 and 6 days. Our findings support the associations between air pollutants and ED visits for cellulitis and other skin conditions.