The incidence of inflammatory bowel disease in the pediatric population of Southwestern Ontario.

PURPOSE: Despite a rising worldwide incidence of inflammatory bowel disease (IBD), few data exist on Canadian children. We reviewed the incidence of IBD in all children 17 years or younger in Southwestern Ontario.
MATERIALS AND METHODS: A chart review from 1997 to 2006 revealed 123 children with IBD. Patients were divided into 2 groups according to year of diagnosis: group 1 = 1997 to 2001 and group 2 = 2002 to 2006. Our catchment population was determined from census data.
RESULTS: Sex (group 1 = 52% females; group 2 = 45% females, P = .42) and age (group 1 = 12.4 +/- 3.6 years; group 2 = 12.9 +/- 3.5 years; P = .43) were similar between groups. Although the overall incidence of IBD decreased (group 1 = 14.3 cases/100,000; group 2 = 12.4 cases/100,000), the incidence of Crohn's disease nearly doubled (group 1 = 3.5 cases/100,000; group 2 = 6.01 cases/100,000) while the incidence of ulcerative colitis decreased substantially (group 1 = 10.6 cases/100,000; group 2 = 6.01 cases/100,000). The incidence of indeterminate colitis was 0.2 cases/100,000 for group 1 and 0.4 cases/100,000 for group 2. The rate of surgical intervention decreased over time, with 43% of patients requiring surgery in group 1 and 31% in group 2 (P = .17).
CONCLUSION: Despite a slight decrease in pediatric IBD incidence in Southwestern Ontario, the incidence of Crohn's disease has nearly doubled over the last decade. Reasons for this remain unclear, although given the relatively short time interval, environmental factors, rather than genetic changes, seem more likely.