Air pollution and emergency department visits for epistaxis.

OBJECTIVES: This study aimed to evaluate the association between outdoor ambient air pollution and emergency department (ED) visits for epistaxis. DESIGN: Cross-sectional study, case-crossover design. SETTING: ED visit data were obtained for Edmonton, Alberta, Canada, for a period of 10 years starting 1 April 1992 and ending March 31st of 2002. The data on ED visits were supplied by Capital Health for the five major acute care hospitals in the Edmonton area. PARTICIPANTS: The analysis was performed for the population as a whole (N = 15 038) and split by sex: males (N = 8587) and females (N = 6451). MAIN OUTCOME MEASURES: We explored associations between ambient concentrations of air pollutants (CO, NO2 , SO2 , O3 , PM10 , PM2.5 ) lagged by 0-4 days and ED visits for epistaxis in Edmonton, Alberta, Canada. RESULTS: Odds ratios (ORs) and their 95% confidence intervals (CI) were reported for an increase in an interquartile range (IQR) of pollutant concentration. We obtained positive and statistically significant results for all patients with epistaxis; exposure to O3 with IQR = 14 ppb, OR = 1.05 (95% CI: 1.00-1.09, lag 0), and for males (age < 25 years), OR = 1.16 (1.03-1.30), lag 4; and to PM10 with IQR = 15 µg/m(3) , OR = 1.02 (1.00-1.05, lag 3). These results were stronger for older (age > 24 years) females. CONCLUSIONS: These findings suggest that there may be an association between air pollutant exposure, specifically ozone and PM10 , and the number of ED visits for epistaxis.