title: A characterization in childhood inflammatory bowel disease, a new population-based inception cohort from South-Eastern Norway, 2005-07, showing increased incidence in Crohn's disease.
abstract: OBJECTIVE
  Owing to rising incidence rates in inflammatory bowel disease (IBD), there has been increased interest in causal relationships in pediatric disease. The present population-based inception cohort was recruited in the Oslo area from 2005 to 2007, with the aim of conducting a detailed characterization of treatment-naive patients at diagnosis.
  
  
  METHODS
  After an invitation was extended to all general practitioners in the catchment area, patients aged <18 years with suspected IBD were diagnosed by proximal and distal endoscopy, MRI, demographic, clinical, and histological and molecular characteristics. Symptomatic non-IBD patients served as controls.
  
  
  RESULTS
  Of 100 pediatric patients, 62 had IBD (39 Crohn's disease (CD), 19 ulcerative colitis (UC), 4 IBD unclassified (IBDU)) and 38 other diseases. Median age at diagnosis for IBD was 13.1 years (56.4% males), median symptom duration 6 months, and 69% L3 (Vienna classification). With 195,000 children aged <18 years in the catchment area, the incidence rate of IBD per 100,000/years inhabitants was 10.9 (6.8 for CD, 3.6 for UC, and 0.6 IBDU) and for those aged <16 years (178,500) the incidence rate was 10.6. The higher NOD2 allele frequency among children may partly contribute to the increase.
  
  
  CONCLUSIONS
  The results indicate a marked rise in the incidence of CD in contrast to no increase in UC in South-Eastern Norway, compared with the figures from the last 15 years. Time from onset of symptoms to diagnosis still represents a challenge for early characterization in IBD.
authors.affiliation: Department of Pediatrics, Akershus University Hospital, Lørenskog and Ullevål University Hospital, Oslo, Norway. gori.perminow@medisin.uio.no
authors.forename: Gøri
authors.initials: G
authors.lastname: Perminow
authors.forename: Stephan
authors.initials: S
authors.lastname: Brackmann
authors.forename: Lars G
authors.initials: LG
authors.lastname: Lyckander
authors.forename: Andre
authors.initials: A
authors.lastname: Franke
authors.forename: Arne
authors.initials: A
authors.lastname: Borthne
authors.forename: Andreas
authors.initials: A
authors.lastname: Rydning
authors.forename: Geir
authors.initials: G
authors.lastname: Aamodt
authors.forename: Stefan
authors.initials: S
authors.lastname: Schreiber
authors.forename: Morten H
authors.initials: MH
authors.lastname: Vatn
mesh_terms: D000293:Adolescent; D017677:Age Distribution; D017668:Age of Onset; D002391:Catchment Area, Health; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003093:Colitis, Ulcerative / Q000175:diagnosis / Q000453:epidemiology* / Q000628:therapy; D003424:Crohn Disease / Q000175:diagnosis / Q000453:epidemiology* / Q000628:therapy; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D008297:Male; D009664:Norway / Q000453:epidemiology; D017678:Sex Distribution