title: High altitude journeys and flights are associated with an increased risk of flares in inflammatory bowel disease patients.
abstract: OBJECTIVE
  Hypoxia can induce inflammation in the gastrointestinal tract. However, the impact of hypoxia on the course of inflammatory bowel disease (IBD) is poorly understood. We aimed to evaluate whether flights and/or journeys to regions lying at an altitude of >2000 m above the sea level are associated with flare-ups within 4 weeks of the trip.
  
  
  METHODS
  IBD patients with at least one flare-up during a 12-month observation period were compared to a group of patients in remission. Both groups completed a questionnaire.
  
  
  RESULTS
  A total of 103 IBD patients were included (43 with Crohn's disease (CD): mean age 39.3 ± 14.6 years; 60 with ulcerative colitis (UC): mean age 40.4 ± 15.1 years). Fifty-two patients with flare-ups were matched to 51 patients in remission. IBD patients experiencing flare-ups had more frequently undertaken flights and/or journeys to regions >2000 m above sea level within four weeks of the flare-up when compared to patients in remission (21/52 [40.4%] vs. 8/51 [15.7%], p=0.005).
  
  
  CONCLUSIONS
  Journeys to high altitude regions and/or flights are a risk factor for IBD flare-ups occurring within 4 weeks of travel.
authors: Division of Gastroenterology and Hepatology, Stadtspital Triemli, Zurich, Switzerland; Division of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland. Electronic address: stephan.vavricka@usz.ch.
authors: Stephan R
authors: SR
authors: Vavricka
authors: Division of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland.
authors: Gerhard
authors: G
authors: Rogler
authors: Division of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland.
authors: Sandra
authors: S
authors: Maetzler
authors: Division of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland.
authors: Benjamin
authors: B
authors: Misselwitz
authors: Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland.
authors: Ekaterina
authors: E
authors: Safroneeva
authors: Division of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland.
authors: Pascal
authors: P
authors: Frei
authors: Division of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland.
authors: Christine N
authors: CN
authors: Manser
authors: Division of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland.
authors: Luc
authors: L
authors: Biedermann
authors: Division of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland.
authors: Michael
authors: M
authors: Fried
authors: Division of Gastroenterology, University of Michigan, Ann Arbor, MI, USA.
authors: Peter
authors: P
authors: Higgins
authors: Division of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland.
authors: Kacper A
authors: KA
authors: Wojtal
authors: Division of Gastroenterology and Hepatology, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland. Electronic address: alain.schoepfer@chuv.ch.
authors: Alain M
authors: AM
authors: Schoepfer
mesh_terms: D000328:Adult; D000337:Aerospace Medicine; D064870:Air Travel; D000531:Altitude; D003093:Colitis, Ulcerative / Q000209:etiology* / Q000503:physiopathology; D003424:Crohn Disease / Q000209:etiology* / Q000503:physiopathology; D018450:Disease Progression; D006801:Humans; D000860:Hypoxia / Q000150:complications*; D008875:Middle Aged; D012307:Risk Factors; D011795:Surveys and Questionnaires; D013997:Time Factors; D055815:Young Adult
keywords: Crohn's disease; Hypoxia; Hypoxic stress; Inflammatory bowel disease; Ulcerative colitis