Association between the use of antibiotics and new diagnoses of Crohn's disease and ulcerative colitis.

OBJECTIVES: The objective of this study was to determine if the use of antibiotics 2-5 years before diagnosis was associated with the development of inflammatory bowel disease (IBD).

METHODS: This was a nested case-control analysis of the population-based University of Manitoba Inflammatory Bowel Disease Epidemiologic Database. A total of 2,234 subjects diagnosed with IBD between 2001 and 2008 were matched to 22,346 controls, based on age, sex, and geographic region. Antibiotic data were drawn from the Manitoba Drug Program Information Network, a comprehensive database of all prescription drugs for all Manitobans dating back to 1995.

RESULTS: The mean age at diagnosis was 43.4 years. In all, 12% of cases had ≥3 prescriptions 2 years before the case date, compared with 7% of controls. The odds ratio for those receiving ≥3 dispensations 2 years before their study inclusion was 1.5 (95% confidence interval: 1.3,1.8; P<0.0001) of being an IBD case. This difference in ≥3 dispensations between cases and controls was fairly consistent at 3, 4, and 5 years before IBD case date. Antibiotic dispensations were associated with both Crohn's disease (CD) and ulcerative colitis (UC), with the association nominally stronger in CD cases for ≥1 and ≥2 dispensations, while the association was stronger in UC cases for ≥3 dispensations. A dose-dependent relationship between the number of antibiotic dispensations, and the risk of IBD was observed across all years investigated.

CONCLUSIONS: Subjects diagnosed with IBD were more likely to have been prescribed antibiotics 2-5 years before their diagnosis. This possibly implicates antibiotic use as a predisposing factor in IBD etiology.