Increasing incidence of inflammatory bowel diseases between 2000 and 2007: A nationwide register study in Finland

Background: The incidence of inflammatory bowel disease (IBD) is high in Western countries, but during the last decade the figures have stabilized, or only slightly increased; at the same time, an increasing incidence rate has been observed in Eastern Europe and Asia. The purpose of this study was to estimate the incidence of IBD in Finland between 2000 and 2007. Methods: New IBD cases between 2000-2007 were retrieved from the national database of special reimbursements for drugs costs. The register includes virtually all Finnish IBD patients since 1986. The incidence rates were calculated per 100,000 persons assuming a Poisson distribution. Results: In total, 14,214 IBD patients were identified; 10,352 had ulcerative colitis (UC) and 3,862 had Crohn's disease (CD). During the whole study period the mean annual incidence of IBD per 1000,000 was 34.0: in CD 9.2 and in VC 24.8. The incidence of UC was notably higher in males (27.8) than in females (21.9). In CD the incidence rates did not differ significantly between genders. The incidence of UC increased from 22.1 in 2000-2001 to 27.4 in 2006-2007. The incidence of CD increased only slightly. Conclusion: In Finland, the incidence of IBD is high, and UC is almost three times more common than CD. During the new millennium the incidence rate of UC has increased, while the incidence rate of CD has remained fairly stable. To the best of our knowledge, the incidence of UC in this nationwide register study is one of the highest reported to date.