title: Environmental factors in inflammatory bowel disease: a case-control study based on a Danish inception cohort.
abstract: BACKGROUND
  The role of environmental factors in development of inflammatory bowel disease (IBD) remains uncertain. The aim of the present study was to assess a number of formerly suggested environmental factors in a case-control study of an unselected and recently diagnosed group of patients with IBD and a control group of orthopaedic patients.
  
  
  METHODS
  A total of 123 patients diagnosed with Crohn's disease (CD) and 144 with ulcerative colitis (UC) in Copenhagen (2003-2004) were matched 1:1 on age and gender to 267 orthopaedic controls. Participants received a questionnaire with 87 questions concerning environmental factors prior to IBD/orthopaedic admission. Odds ratios (OR) were calculated by logistic regression.
  
  
  RESULTS
  Being breastfed >6 months (OR, 0.50; 95% CI, 0.23-1.11) and undergoing tonsillectomy (OR, 0.49; 95% CI, 0.31-0.78) decreased the odds for IBD, whereas appendectomy decreased the odds for UC only (OR, 0.29; 95% CI, 0.12-0.71). Vaccination against pertussis (OR, 2.08; 95% CI, 1.07-4.03) and polio (OR, 2.38; 95% CI, 1.04-5.43) increased the odds for IBD, whereas measles infection increased the odds for UC (OR, 3.50; 95% CI, 1.15-10.6). Low consumption of fibres and high consumption of sugar were significantly associated with development of CD and UC. Smoking increased the risk for CD and protected against UC.
  
  
  CONCLUSIONS
  Among Danish patients with CD and UC belonging to an unselected cohort, disease occurrence was found to be associated both with well-known factors such as smoking and appendectomy, and with more debated factors including breastfeeding, tonsillectomy, childhood vaccinations, childhood infections, and dietary intake of fibres and sugar.
authors: Gastrointestinal Unit, Medical Section, Herlev University Hospital, Statens Serum Institut, Copenhagen, Denmark.
authors: Tanja Stenbaek
authors: TS
authors: Hansen
authors: Tine
authors: T
authors: Jess
authors: Ida
authors: I
authors: Vind
authors: Margarita
authors: M
authors: Elkjaer
authors: Malene Fey
authors: MF
authors: Nielsen
authors: Michael
authors: M
authors: Gamborg
authors: Pia
authors: P
authors: Munkholm
mesh_terms: D001062:Appendectomy / Q000009:adverse effects; D001942:Breast Feeding / Q000009:adverse effects; D016022:Case-Control Studies; D015331:Cohort Studies; D003093:Colitis, Ulcerative / Q000453:epidemiology / Q000209:etiology*; D003424:Crohn Disease / Q000453:epidemiology / Q000209:etiology*; D003718:Denmark / Q000453:epidemiology; D004043:Dietary Fiber / Q000009:adverse effects; D019422:Dietary Sucrose / Q000009:adverse effects; D004777:Environment; D006801:Humans; D016015:Logistic Models; D008457:Measles / Q000453:epidemiology; D016017:Odds Ratio; D010567:Pertussis Vaccine / Q000009:adverse effects; D023321:Poliovirus Vaccines / Q000009:adverse effects; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects; D011795:Surveys and Questionnaires; D014068:Tonsillectomy / Q000009:adverse effects
chemical_list: D004043:Dietary Fiber; D019422:Dietary Sucrose; D010567:Pertussis Vaccine; D023321:Poliovirus Vaccines