title: Genetic and environmental factors as predictors of disease severity and extent at time of diagnosis in an inception cohort of inflammatory bowel disease, Copenhagen County and City 2003-2005.
abstract: OBJECTIVE
  The etiology of the inflammatory bowel diseases (IBD), Crohn's disease (CD) and ulcerative colitis (UC) remains unknown. We aimed to investigate the influence of genetic, serological, and environmental factors on phenotypic presentation of IBD at diagnosis in a population-based Danish inception cohort from 2003-2005.
  
  
  METHODS
  Three-hundred-forty-seven (62%) of 562 cohort patients were genotyped. ASCA and p/c-ANCA were determined and patients answered a questionnaire concerning environmental factors with possible influence on IBD.
  
  
  RESULTS
  Fourteen percent of CD patients vs. 11% of controls were positive for common CARD15 mutation (ns), whereas more CD patients than healthy controls were homozygous for the OCTN-TC haplotype (p=0.03). ASCA was more common in CD (22%) than UC (14%) (p=0.045) and was related to age and localization of CD. p-ANCA was more frequent in UC (p=0.00001) but was related to pure colonic CD (p=0.0001). Sugar consumption was significantly higher in CD patients than in UC patients (p=0.0001) and more CD patients than UC patients had undergone appendectomy prior to IBD diagnosis (p=0.03). A possible relation between tonsillectomy and disease severity in CD, and a relation between use of oral contraception and disease localization of UC to rectum/left-sided colon were found.
  
  
  CONCLUSIONS
  In this cohort of unselected IBD patients we found a very low frequency of mutations in IBD susceptibility genes and observed a greater impact of ASCA and ANCA than of genetic factors on disease phenotypes. In addition, several environmental factors seemed to influence disease occurrence and disease presentation in both UC and especially CD.
authors.affiliation: Department of Gastroenterology, Hvidovre Hospital, University of Copenhagen, Denmark.
authors.forename: Ida
authors.initials: I
authors.lastname: Vind
authors.forename: Lene
authors.initials: L
authors.lastname: Riis
authors.forename: Cathrine
authors.initials: C
authors.lastname: Jespersgaard
authors.forename: Tine
authors.initials: T
authors.lastname: Jess
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Knudsen
authors.forename: Natalia
authors.initials: N
authors.lastname: Pedersen
authors.forename: Margarita
authors.initials: M
authors.lastname: Elkjaere
authors.forename: Tanja Stenbaek
authors.initials: TS
authors.lastname: Hansen
authors.forename: Inger Bak
authors.initials: IB
authors.lastname: Andersen
authors.forename: Anders
authors.initials: A
authors.lastname: Paerregaard
authors.forename: Stig
authors.initials: S
authors.lastname: Bondesen
authors.forename: Henning
authors.initials: H
authors.lastname: Locht
authors.forename: Severin Olesen
authors.initials: SO
authors.lastname: Larsen
authors.forename: Flemming
authors.initials: F
authors.lastname: Moesgaard
authors.forename: Flemming
authors.initials: F
authors.lastname: Bendtsen
authors.forename: Paal Skytt
authors.initials: PS
authors.lastname: Andersen
authors.forename: Pia
authors.initials: P
authors.lastname: Munkholm