Background: The present study aimed to characterize the incidence of pediatric inflammatory bowel disease (IBD) in Finland and determine its temporal trends.

Methods: The patients' data were based on the database of the Social Insurance Institution. New cases diagnosed with IBD at the age <18 years in Finland between years 1987-2003 were included. Annual incidence rates were calculated per 100,000 pediatric populations (with 95% confidence intervals [CI]). The country is divided into 21 hospital districts and regional differences were evaluated accordingly.

Results: The incidence of pediatric IBD increased from 5 per 100,000 in 1987 to 15 per 100,000 in 2003. The average rate of increase was 6.5% per year (95% CI 5.4%-7.5%). The trends were comparable for boys and girls, also by age group. Information on disease subtype was available from 1992 and during this 12-year period the incidence of Crohn's disease (CD) increased from 2-5 per 100,000 and that of ulcerative colitis (UC) from 4-9 per 100,000.

Conclusions: Our results demonstrate a very high incidence rate for childhood IBD and in particular UC in Finland. Furthermore, a rapid increase took place nationwide in the incidence of both CD and UC during the past two decades.