Conjunctivitis Etiology Diagnosis and Clinical Management
Air pollution and emergency department visits for conjunctivitis in calgary, Canada: A case crossover study
Kousha, T; Castner, J
Objectives: Ambient air pollution exposure has been associated with the occurrence of several different health conditions. These associations are not only limited to respiratory and cardiovascular system; there have been also number of studies that have linked ambient air pollutions to non-respiratory conditions, such as cardiac disease, appendicitis, headaches and migraines, skin conditions, eye discomfort and conjunctivitis. The purpose of this study was to examine the associations between emergency department (ED) visits for conjunctivitis and ambient air pollution levels in Calgary, Alberta, Canada. Materials and Methods: The National Ambulatory Care Reporting System was used to obtain patient information on ED visits for conjunctivitis for the period of January 2010 to December 2011. ED visits for conjunctivitis were defined using the International Classification of Diseases, Tenth revision (ICD-10) codes H10. A time stratified casecrossover design was applied in this study. Odds ratios (ORs) and their 95% confidence intervals (95%CI) for emergency department visits were calculated for one unit increase in each pollutant (nitrogen dioxide (NO2), fine particulate matter with a median aerodynamic diameter of less than 2.5 μm (PM2.5) and ozone (O3)), controlling for temperature and relative humidity. Results: Among 4,333 ED visits for conjunctivitis (49% females, 51 % males), analyses were conducted considering cold weather months (October to March) and warm weather months (April to September). During the warm months, statistically significant positive results were observed in the female population for NO2 and for lags 5-7 days, with the highest result for lag 5 days (OR = 1.048; 95%CI = 1.020, 1.076) and in the male population for PM2.5 lagged 6 days (OR = 1.014; 95%CI = 1.002, 1.026). During the cold months, statistically significant positive results were observed for females and NO2 lagged 7 days (OR = 1.021; 95%CI = 1.001, 1.040) and for PM2.5 for lag 2 days (OR = 1.042; 95%CI = 1.004, 1.079) and for males and O3 lagged 5 and 6 days, with the highest result for lag 6 (OR = 1.035; 95%CI = 1.009, 1.062). Conclusion: The findings of this study suggest that there are associations between level of air pollution and ED visits for conjunctivitis in Calgary, Canada. Our findings support associations reported in the literature for NO2 among females. The latency period between exposure and ED visit for conjunctivitis in this study coincides with the typical incubation period for infectious conjunctivitis.
