title: Modifiable Environmental Factors in Inflammatory Bowel Disease.
abstract: OBJECTIVE
  Environmental factors may influence predisposition to develop inflammatory bowel diseases (Crohn's disease, ulcerative colitis) or alter its natural history by modification of both the host immune response and intestinal microbial composition. The purpose of this review is to translate such evidence into clinical practice by a focus on interventional studies that have modified such environmental influences to improve disease outcomes.
  
  
  RESULTS
  Several environmental influences have been identified in the recent literature including tobacco use, diet, antibiotics, vitamin D deficiency, stress, appendectomy, and oral contraceptive use. Some risk factors have similar influences on both Crohn's disease and ulcerative colitis while others are disease-specific or have divergent effects. Emerging epidemiologic evidence has confirmed the association of many of these factors with incident disease using prospective data. In addition, laboratory data has supported their mechanistic plausibility and relevance to intestinal inflammation.
authors.affiliation: Division of Gastroenterology, Massachusetts General Hospital, Boston, USA.
authors.forename: Kristin E
authors.initials: KE
authors.lastname: Burke
authors.affiliation: Division of Gastroenterology, University of Missouri-Columbia, Columbia, USA.
authors.forename: Christine
authors.initials: C
authors.lastname: Boumitri
authors.affiliation: Division of Gastroenterology, Massachusetts General Hospital, Boston, 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: D004032:Diet / Q000009:adverse effects; D019587:Dietary Supplements; D004750:Enteral Nutrition / Q000379:methods; D004777:Environment; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000209:etiology* / Q000628:therapy; D012307:Risk Factors; D012893:Sleep Wake Disorders / Q000150:complications; D012907:Smoking / Q000009:adverse effects; D013315:Stress, Psychological / Q000150:complications
keywords: Crohn’s disease; Diet; Environment; Smoking; Ulcerative colitis