title: The association between childhood environmental exposures and the subsequent development of Crohn's disease in the Western Cape, South Africa.
abstract: BACKGROUND
  Environmental factors during childhood are thought to play a role in the aetiolgy of Crohn's Disease (CD). However the association between age at time of exposure and the subsequent development of CD in South Africa is unknown.
  
  
  METHODS
  A case control study of all consecutive CD patients seen at 2 large inflammatory bowel disease (IBD) referral centers in the Western Cape, South Africa between September 2011 and January 2013 was performed. Numerous environmental exposures during 3 age intervals; 0-5, 6-10 and 11-18 years were extracted using an investigator administered questionnaire. An agreement analysis was performed to determine the reliability of questionnaire data for all the relevant variables.
  
  
  RESULTS
  This study included 194 CD patients and 213 controls. On multiple logistic regression analysis, a number of childhood environmental exposures during the 3 age interval were significantly associated with the risk of developing CD. During the age interval 6-10 years, never having had consumed unpasteurized milk (OR = 5.84; 95% CI, 2.73-13.53) and never having a donkey, horse, sheep or cow on the property (OR = 2.48; 95% CI, 1.09-5.98) significantly increased the risk of developing future CD. During the age interval 11-18 years, an independent risk-association was identified for; never having consumed unpasteurized milk (OR = 2.60; 95% CI, 1.17-6.10) and second-hand cigarette smoke exposure (OR = 1.93; 95% CI, 1.13-3.35).
  
  
  CONCLUSIONS
  This study demonstrates that both limited microbial exposures and exposure to second-hand cigarette smoke during childhood is associated with future development of CD.
authors.affiliation: Dietetics Department, University of the Western Cape, Bellville, Western Cape, South Africa.
authors.forename: Abigail
authors.initials: A
authors.lastname: Basson
authors.affiliation: Dietetics Department, University of the Western Cape, Bellville, Western Cape, South Africa.
authors.forename: Rina
authors.initials: R
authors.lastname: Swart
authors.affiliation: Biostatistics Unit, Medical Research Council of South Africa, Parow, Western Cape, South Africa; Statistics and Population Studies Department, University of the Western Cape, Bellville, Western Cape, South Africa.
authors.forename: Esme
authors.initials: E
authors.lastname: Jordaan
authors.affiliation: Biostatistics Unit, Medical Research Council of South Africa, Parow, Western Cape, South Africa.
authors.forename: Mikateko
authors.initials: M
authors.lastname: Mazinu
authors.affiliation: Department of Gastroenterology, Groote Schuur Hospital, Cape Town, Western Cape, South Africa, and the Department of Medicine, University of Cape Town, Cape Town, Western Cape, South Africa.
authors.forename: Gillian
authors.initials: G
authors.lastname: Watermeyer
mesh_terms: D000293:Adolescent; D000818:Animals; D000829:Animals, Domestic / Q000276:immunology; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D003424:Crohn Disease / Q000453:epidemiology* / Q000209:etiology*; D004781:Environmental Exposure / Q000009:adverse effects*; D006801:Humans; D007223:Infant; D016015:Logistic Models; D008892:Milk / Q000009:adverse effects; D016017:Odds Ratio; D061352:Pasteurization; D013019:South Africa / Q000453:epidemiology; D011795:Surveys and Questionnaires; D014028:Tobacco Smoke Pollution / Q000009:adverse effects
chemical_list: D014028:Tobacco Smoke Pollution