Epidemiologic and clinical characteristics of children with newly diagnosed inflammatory bowel disease in Wisconsin: a statewide population-based study.

OBJECTIVE: To define epidemiologic and clinical characteristics of newly diagnosed pediatric inflammatory bowel disease (IBD) in a large population-based model. STUDY DESIGN: All pediatric gastroenterologists providing care for Wisconsin children voluntarily identified all new cases of IBD during a 2-year period. Demographic and clinical data were sent to a central registry prospectively for analysis. RESULTS: The incidence of IBD in Wisconsin children was 7.05 per 100,000, whereas the incidence for Crohn's disease was 4.56, more than twice the rate of ulcerative colitis (2.14). An equal IBD incidence occurred among all ethnic groups, and children from sparsely and densely populated counties were equally affected. The majority (89%) of new IBD diagnoses were nonfamilial. CONCLUSIONS: This study provides novel, prospective, and comprehensive information on pediatric IBD incidence within the United States. The surprisingly high incidence of pediatric IBD, the predominance of Crohn's disease over ulcerative colitis, the low frequency of patients with a family history, the equal distribution of IBD among all racial and ethnic groups, and the lack of a modulatory effect of urbanization on IBD incidence collectively suggest that the clinical spectrum of IBD is still evolving and point to environmental factors contributing to the pathogenesis.