title: Early life environment and natural history of inflammatory bowel diseases.
abstract: BACKGROUND
  Early life exposures may modify risk of inflammatory bowel diseases (IBD; Crohn's disease (CD), ulcerative colitis (UC)). However, the relationship between early life exposures and natural history of IBD has not been previously examined.
  
  
  METHODS
  This single center study included patients with CD or UC recruited in a prospective IBD registry. Enrolled patients completed a detailed environmental questionnaire that assessed various early life environmental exposures. Our primary outcome was requirement for disease-related surgery in CD and UC. Logistic regression models defined independent effect of early life exposures, adjusting for potential confounders.
  
  
  RESULTS
  Our study included 333 CD and 270 UC patients. Just over half were female with a median age at diagnosis of 25 years. One-third of the cohort had history of bowel surgery (31%) and nearly half had used at least one biologic agent (47%). Among those with CD, being breastfed was associated with reduced risk of CD-related surgery (34% vs. 55%), while childhood cigarette smoke exposure was associated with increased risk. On multivariate analysis, history of being breastfed (odds ratio (OR) 0.21, 95% confidence interval [CI] 0.09-0.46) and cigarette smoke exposure as a child (OR 2.17, 95% CI 1.10-4.29) remained independently associated with surgery. None of the early life variables influenced disease phenotype or outcome in UC.
  
  
  CONCLUSIONS
  A history of being breastfed was associated with a decreased risk while childhood cigarette smoke exposure was associated with an increased risk of surgery in patients with CD. Further investigation to examine biological mechanisms is warranted.
authors.affiliation: Division of Gastroenterology, Massachusetts General Hospital, Boston, MA, USA. aguo1@mgh.harvard.edu.
authors.forename: Abra Y
authors.initials: AY
authors.lastname: Guo
authors.affiliation: Division of Gastroenterology, Massachusetts General Hospital, Boston, MA, USA. bstevens1@partners.org.
authors.forename: Betsy W
authors.initials: BW
authors.lastname: Stevens
authors.affiliation: Division of Gastroenterology, Massachusetts General Hospital, Boston, MA, USA. rgwilson@mgh.harvard.edu.
authors.forename: Robin G
authors.initials: RG
authors.lastname: Wilson
authors.affiliation: Division of Gastroenterology, Massachusetts General Hospital, Boston, MA, USA. cnrussell@mgh.harvard.edu.
authors.forename: Caitlin N
authors.initials: CN
authors.lastname: Russell
authors.affiliation: Division of Gastroenterology, Massachusetts General Hospital, Boston, MA, USA. mcohen4@mgh.harvard.edu.
authors.forename: Melissa A
authors.initials: MA
authors.lastname: Cohen
authors.affiliation: Division of Gastroenterology, Massachusetts General Hospital, Boston, MA, USA. hsturgeon@mgh.harvard.edu.
authors.forename: Holly C
authors.initials: HC
authors.lastname: Sturgeon
authors.affiliation: Division of Gastroenterology, Massachusetts General Hospital, Boston, MA, USA. athornton4@mgh.harvard.edu.
authors.forename: Anna
authors.initials: A
authors.lastname: Thornton
authors.affiliation: Division of Gastroenterology, Massachusetts General Hospital, Boston, MA, USA. cgiallourakis@mgh.harvard.edu.|Harvard Medical School, Boston, MA, USA. cgiallourakis@mgh.harvard.edu.
authors.forename: Cosmas
authors.initials: C
authors.lastname: Giallourakis
authors.affiliation: Division of Gastroenterology, Massachusetts General Hospital, Boston, MA, USA. hkhalili@mgh.harvard.edu.|Harvard Medical School, Boston, MA, USA. hkhalili@mgh.harvard.edu.
authors.forename: Hamed
authors.initials: H
authors.lastname: Khalili
authors.affiliation: Division of Gastroenterology, Massachusetts General Hospital, Boston, MA, USA. deanna.nguyen@mgh.harvard.edu.|Harvard Medical School, Boston, MA, USA. deanna.nguyen@mgh.harvard.edu.
authors.forename: Deanna D
authors.initials: DD
authors.lastname: Nguyen
authors.affiliation: Division of Gastroenterology, Massachusetts General Hospital, Boston, MA, USA. jsauk@mgh.harvard.edu.|Harvard Medical School, Boston, MA, USA. jsauk@mgh.harvard.edu.
authors.forename: Jenny
authors.initials: J
authors.lastname: Sauk
authors.affiliation: Division of Gastroenterology, Massachusetts General Hospital, Boston, MA, USA. vyajnik@mgh.harvard.edu.|Harvard Medical School, Boston, MA, USA. vyajnik@mgh.harvard.edu.
authors.forename: Vijay
authors.initials: V
authors.lastname: Yajnik
authors.affiliation: Division of Gastroenterology, Massachusetts General Hospital, Boston, MA, USA. rxavier@mgh.harvard.edu.|Harvard Medical School, Boston, MA, USA. rxavier@mgh.harvard.edu.
authors.forename: Ramnik J
authors.initials: RJ
authors.lastname: Xavier
authors.affiliation: Division of Gastroenterology, Massachusetts General Hospital, Boston, MA, USA. aananthakrishnan@mgh.harvard.edu.|Massachusetts General Hospital Crohn's and Colitis Center, 165 Cambridge Street, 9th Floor, Boston, MA, 02114, USA. aananthakrishnan@mgh.harvard.edu.
authors.forename: Ashwin N
authors.initials: AN
authors.lastname: Ananthakrishnan
mesh_terms: D001942:Breast Feeding; D003093:Colitis, Ulcerative / Q000453:epidemiology* / Q000601:surgery; D003424:Crohn Disease / Q000453:epidemiology* / Q000601:surgery; D018450:Disease Progression; D004781:Environmental Exposure; D005260:Female; D006801:Humans; D008297:Male; D008404:Massachusetts / Q000453:epidemiology; D011446:Prospective Studies; D012042:Registries; D012307:Risk Factors; D011795:Surveys and Questionnaires; D014028:Tobacco Smoke Pollution / Q000009:adverse effects
chemical_list: D014028:Tobacco Smoke Pollution