Incidence of inflammatory bowel disease in Finnish children, 1987-2003

Background: The incidence of inflammatory bowel disease (IBD) has been increasing in Western countries. In younger people, Crohn's disease (CD) predominates over ulcerative colitis (UC), but the finding is not universal. The present study aimed to characterize not only the incidence but also the clinical picture of IBD from 1987 to 2003 in a large pediatric population in Finland. Materials and Methods: Data were collected from the patient discharge and medical records at the 2 largest university hospitals in Finland. The study population covered a total of 619,340 children, representing 56% of the children <18 years old in the country. All of the cases diagnosed with IBD from 1987 to 2003 were reviewed. Clinical, endoscopic, and histological data were collected. Incidence rates were estimated based on statistical assumptions. Results: A total of 604 cases with IBD were diagnosed during the 17-year period. All of the patients had undergone endoscopy. The diagnosis was CD in 203 (34%) cases, UC in 317 (52%) cases, and indeterminate colitis (IC) in 83 (14%) cases. The mean annual incidence rate increased from 3.9/100,000 (95% confidence interval [CI] 2.5-5.8) in 1987 to 7.0/100,000 (Cl 5.0-9.4) in 2003 (P < 0.001). The majority of cases were 12 to <15 years old (n = 200, 33%). Of the patients, 5.1% were <3 years old and 14% were <6 years old. IC was most common in young children; 29% of all IBD patients <3 years of age had IC. Of the patients, 97% had been followed up until the age 18 in the hospitals after initial diagnosis (median follow-up 3.1 years). Of the patients, 45.2% were initially treated with steroids, whereas 17.8% received immunosuppressive agents at the end of the follow-up. Operations had been performed in 21% of the cases before age 18. The median time interval from the diagnosis to the first operation was 1.8 (range 7.8) years. Conclusions: The incidence of pediatric IBD almost doubled in Finland from 1987 to 2003. Surgical intervention was common early in the disease course.