title: The effect of cigarette smoking on the clinical course of inflammatory bowel disease.
abstract: BACKGROUND
  Cigarette smoking is considered an important risk factor for developing Crohn's disease (CD), contributing to a more severe course of the disease. Conversely, smoking is believed to have a beneficial effect on the course of ulcerative colitis (UC), a second major condition of inflammatory bowel disease (IBD).
  
  
  OBJECTIVE
  To investigate the effect of tobacco use on the clinical course of IBD.
  
  
  METHODS
  A group of 95 adults with IBD were enrolled to the study. Demographic and clinical data of patients as well as their smoking status were analysed based on their medical history. Values were considered significant when p ≤ 0.05.
  
  
  RESULTS
  Current smokers constituted the majority of CD patients. They tended to develop a more severe course of the disease, compared to former smokers and non-smokers. Current smokers suffered a moderate-to-severe form of the disease and required immunosuppressive therapy more frequently. They were also hospitalised and underwent surgeries more frequently than patients from other investigated subgroups. The study failed, however, to fully confirm the beneficial effect of smoking on the clinical outcome of UC. The investigated non-smokers and former smokers suffered a more severe disease, but the analysis did not find any statistical differences in the frequencies of hospitalisations nor immunosuppressant usage among the investigated subgroups.
  
  
  CONCLUSIONS
  The study confirmed a detrimental effect of smoking on the outcome of CD, but failed to fully confirm its beneficial effect on UC.
authors.affiliation: Department of Biology and Environmental Sciences, Laboratory of Transplant Immunology, Poznan University of Medical Sciences, Poznan, Poland.
authors.forename: Jacek
authors.initials: J
authors.lastname: Karczewski
authors.affiliation: Department of Biology and Environmental Sciences, Laboratory of Transplant Immunology, Poznan University of Medical Sciences, Poznan, Poland.
authors.forename: Barbara
authors.initials: B
authors.lastname: Poniedziałek
authors.affiliation: Department of Biology and Environmental Sciences, Laboratory of Transplant Immunology, Poznan University of Medical Sciences, Poznan, Poland.
authors.forename: Piotr
authors.initials: P
authors.lastname: Rzymski
authors.affiliation: Department of Biology and Environmental Sciences, Laboratory of Transplant Immunology, Poznan University of Medical Sciences, Poznan, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Rychlewska-Hańczewska
authors.affiliation: Department of Biology and Environmental Sciences, Laboratory of Transplant Immunology, Poznan University of Medical Sciences, Poznan, Poland.
authors.forename: Zygmunt
authors.initials: Z
authors.lastname: Adamski
authors.affiliation: Department of Biology and Environmental Sciences, Laboratory of Transplant Immunology, Poznan University of Medical Sciences, Poznan, Poland.
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Wiktorowicz
keywords: Crohn's disease; inflammatory bowel disease; smoking; ulcerative colitis
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