Role of Air Pollution in Inflammatory Bowel Disease Flares: A Retrospective Study

Background: To evaluate relation between air pollution and rate of flare and hospital admission among inflammatory bowel disease (IBD) patients. Materials and Methods: In this retrospective study، during a 10 months period، the number and average duration of hospitalization of patients admitted in GI ward due to IBD flare were recorded in an industrial capital city. Concomitantly the level of 4 major air pollutants including SO2، CO، NO2 and O3 measured and the correlation between severity of IBD flare and air pollution determined by Pearson correlation coefficient. Results: Average number of admission was 7 patients per month (1-12). This figure for Crohnʹʹs disease (CD) was 2.9 and 3.7 for ulcerative colitis (UC). The average duration of hospitalization for UC and CD were 2.8 days (1–13) and 2.9 days (1–22) respectively. After comparison of average concentration of 4 major air pollutants with rate of IBD flare، ، there was a relation، although non-meaningful، between CO concentration and number and duration of admissions due to UC flare (p=0.135 & 0.08، correlation coefficient 0.196 & 0.251 respectively). DATA analysis did not reveal any significant relation between SO2 and NO2 and the rate of admission due to IBD flare (p>0.05) and Interestingly there were a reverse meaningful correlation between concentration of O3 and number and duration of admissions due to Crohn’s disease flare (p=0.016 and 0.006، Correlation Coefficient -0.338 & -0.413 respectively). Conclusion: It seems that CO as one of the major air pollutants can aggravates course of ulcerative colitis and on the other hand O3 could have a potential protective effect on Crohn’s disease. This issue should further be clarified in future studies.