Inflammatory bowel disease in Icelandic children 1951-2010. Population-based study involving one nation over six decades

Aim and background. We describe the changes in incidence and disease location of inflammatory bowel disease (IBD) in children in one country over six decades. Iceland is an island with centralized health information. Children with IBD are cared for in only two hospitals. Iceland is therefore well suited for nationwide epidemiologic studies. Material and methods. All IBD patients 16 years and younger diagnosed in Iceland from 1950-2010 were included. Patients were identified retrospectively from 1950-1989, and propectively from 1990-2010, by reviewing pathology and charts for all patients diagnosed with IBD. Criteria for the diagnosis of ulcerative colitis (UC) were history of blood in stools for >3 weeks, characteristic endoscopic appearance of continuous inflammation of the colon, and histologic appearance of acute and chronic inflammation of the colon without granulomata. Criteria of Crohn's disease (CD) were history of abdominal pain, blood in stools, and endoscopic, radiologic, and histologic features of CD. Results. One hundred and ten children were diagnosed with IBD, 61 with UC, 44 with CD, and 5 with indeterminate disease. The median age was 13.7 +/- 2.6, with sex distribution varying from decade to decade. From 1980 until 2000, there was a dramatic increase in the incidence of IBD from 1.2 per 100,000 children <16 years of age to 5.6 per 100,000. However, in the past decade, the incidence has plateaued. Conclusion. In this population-based pediatric study, we report an increase in the incidence of IBD from 1950-2000. Incidence in Icelandic children is lower than in published studies from other Northern European countries.