Background and methods: In a geographically derived incidence cohort diagnosed from 1962 to 1987 we identified all patients with onset of inflammatory bowel diseases (IBD) before the age of 15 years, to describe the clinical course and to compare the course and prognosis with those of adult-onset IBD.
Results: The mean incidence of IBD among children below 15 years was 2.2/10(5), 2.0 for ulcerative colitis (UC) and 0.2 for Crohn's disease (CD). At diagnosis children with UC had more extensive disease than adults (P < 0.05). Abdominal pain was also more frequent. The cumulative colectomy probability was 6% after 1 year and 29% after 20 years, not different from that of adults. More females underwent colectomy. With regard to disease activity, apart from the year of diagnosis 60-70% of UC patients were in remission in each of the first 10 years of disease; for CD about 50% were in remission. One patient with UC developed carcinoma of the sigmoid colon. Time between onset of UC and development of carcinoma was 12 years. For CD no differences in clinical appearance at diagnosis and course between children and adults were found in relationship to surgery. No deaths occurred among CD patients. Three CD patients were severely growth-retarded already at diagnosis.
Conclusion: The incidence of IBD is low in childhood. At diagnosis children with UC have more widespread disease than adults. Childhood-onset CD does not differ in clinical presentation, disease course, or prognosis from adult-onset CD. However, growth retardation is a problem among male CD patients.