Epidemiology of inflammatory bowel disease in Québec: recent trends

Among 10 provinces in Canada, Québec has the second highest incidence of Crohn's disease (CD), based on data collected more than a decade ago. To date, there are no reports on the occurrence of ulcerative colitis (UC) and no updates on the occurrence of CD in Québec. We sought to describe trends in the annual incidence and prevalence of inflammatory bowel disease in Québec during 2001 to 2008.

A population-based retrospective cohort study was conducted using the administrative health databases of Québec. IBD cases were identified using a validated case definition requiring at least 1 hospitalization or 4 physician claims within a 2-year period. Incident cases were defined as individuals who had been free of inflammatory bowel disease for at least 2 years before the 2-year time span of the case definition.

We identified 24,377 CD and 15,346 UC cases. The mean age at diagnosis was 39 and 46 years for CD and UC, respectively. There was a significant decline in the annual incidence from 2001 to 2008 for both CD (P < 0.003) and UC (P < 0.001). No significant change with time was found in pediatric cases. The point prevalence in 2008 was 277 CD and 164 UC cases per 100,000 population. The average incidence was 17.4 CD cases per 100,000 person-years and 10.1 UC cases per 100,000 person-years. There was no predominance of urban or rural cases for either CD or UC.

During 2001 to 2008, annual incidence for both CD and UC declined in Québec. There was no significant change with time in incidence for pediatric cases.