Incidence of ulcerative colitis and Crohn's disease in Danish children: Still rising or levelling out?

AIM: To describe the development in incidence and prevalence of paediatric inflammatory bowel disease (IBD) in Eastern Denmark during a six-year period.

METHODS: All patients <15 years with IBD in Eastern Denmark in the two following periods were included: 1) 1.1.1998-31.12.2000 and 2) 1.1.2002-31.12.2004. The mean background population (children <15 years) in Eastern Denmark was 421,898 persons in period 1 and 439,443 persons in period 2. Patients were identified using the ICD-10 classification (DK500-519). The following data were extracted from the files: diagnosis, change in diagnosis, age at diagnosis, localisation, extra-intestinal symptoms, surgery and county of residence. Incidence and prevalence for ulcerative colitis (UC), Crohn's disease (CD) and indeterminate colitis (IC) were calculated per 100,000 children <15 years.

RESULTS: 98 patients (50 UC, 44 CD, 4 IC), median age 9.8 years (range 2-14) and 12.8 (range 0.5-14) for UC and CD, respectively, were identified in period 1. In the second period 145 patients (70 UC, 64 CD, 11 IC) were included with a median age of 11 years (range 1-14) and 12.5 (range 0.5-14) for UC and CD, respectively. The prevalence of IBD was 15.8 and 20.3 in 1998-2000 and 2002-2004, respectively. The incidence of IBD was 4.3 (UC: 1.8; CD: 2.3; IC: 0.2) and 6.1 (UC: 2.6; CD: 3.1; IC: 0.3), respectively, for the two periods (p>0.05).

CONCLUSIONS: In our study we found an insignificant increase in the incidence of both CD and UC, indicating that the previously reported rising incidence might be levelling out.