title: Incidence and clinical course of Crohn's disease during the first year - results from the IBD Cohort of the Uppsala Region (ICURE) of Sweden 2005-2009.
abstract: OBJECTIVE
  As a part of the Swedish ICURE study where the epidemiological results of ulcerative colitis and microscopic colitis recently have been published, we hereby present the corresponding figures for Crohn's disease.
  
  
  METHODS
  All patients diagnosed with Crohn's disease in Uppsala County (305,381 inhabitants) were prospectively registered during 2005-2006 and the same for all new patients with Crohn's disease in Uppsala Region (642,117 inhabitants) during 2007-2009.
  
  
  RESULTS
  264 patients with Crohn's disease were included. The mean annual incidence was 9.9/100,000/year (95% CI: 7.1-12.6). Incidence among children <17 years was 10.0/100,000/year (95% CI: 3.8-16.3). 51% of the patients had ileal involvement (L1: n=73, 28%. L2: n=129, 49%. L3: n=62, 23%, L4: n=47, 18%) and 23% had a stricturing or penetrating disease (B1: n=204, 77%. B2: n=34, 13%. B3: n=26, 10%. p: n=27, 10%). Intestinal resection rate during the first year was 12.5%. Patients with complicated disease had longer symptom duration before diagnosis compared to patients with non-complicated disease (median months 12.0, IQR: 3.0-24.0 vs 4.0, IQR: 2.0-12.0, p=0.0032). Patients 40 years or older had an increased risk for surgery (HR: 2.03, 95% CI: 1.01-4.08, p=0.0457).
  
  
  CONCLUSIONS
  The incidence of Crohn's disease in a region of Sweden is one of the highest reported in Europe. Long symptom duration precedes stricturing or penetrating behaviour. Old age is an independent risk factor for surgery.
authors.affiliation: Department of Internal Medicine, Falu Hospital, Falun, Sweden. Electronic address: daniel.sjoberg@ltdalarna.se.
authors.forename: Daniel
authors.initials: D
authors.lastname: Sjöberg
authors.affiliation: Department of Internal Medicine, Mariehamn, Åland, Finland.
authors.forename: Tommy
authors.initials: T
authors.lastname: Holmström
authors.affiliation: Department of Internal Medicine, Mälar Hospital, Eskilstuna, Sweden.
authors.forename: Märit
authors.initials: M
authors.lastname: Larsson
authors.affiliation: Department of Internal Medicine, Mälar Hospital, Eskilstuna, Sweden.
authors.forename: Anne-Lie
authors.initials: AL
authors.lastname: Nielsen
authors.affiliation: Department of Pediatrics, Uppsala University, Uppsala, Sweden.
authors.forename: Lars
authors.initials: L
authors.lastname: Holmquist
authors.affiliation: Clinical Epidemiology Unit, Department of Medicine, Karolinska Institute, Stockholm, Sweden.
authors.forename: Anders
authors.initials: A
authors.lastname: Ekbom
authors.affiliation: Department of Medical Sciences, Uppsala University, Uppsala, Sweden.
authors.forename: Anders
authors.initials: A
authors.lastname: Rönnblom
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D003092:Colitis / Q000453:epidemiology* / Q000473:pathology / Q000601:surgery; D003251:Constriction, Pathologic / Q000209:etiology / Q000601:surgery; D003424:Crohn Disease / Q000453:epidemiology* / Q000473:pathology / Q000628:therapy; D005260:Female; D006801:Humans; D007079:Ileitis / Q000453:epidemiology* / Q000473:pathology / Q000601:surgery; D015994:Incidence; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D012307:Risk Factors; D013548:Sweden / Q000453:epidemiology; D055815:Young Adult
keywords: Crohn's disease; Epidemiology; Incidence; Inflammatory bowel disease; Surgery