title: Current and past cigarette smoking significantly increase risk for microscopic colitis.
abstract: BACKGROUND
  Cigarette smoking is an important environmental factor affecting inflammatory bowel disease. The role of smoking has not been rigorously studied in microscopic colitis (MC). The aim of this study was to compare the association of cigarette smoking in individuals with MC compared to a control population without MC.
  
  
  METHODS
  We reviewed the records of patients with a clinical and histologic diagnosis of collagenous colitis (CC) or lymphocytic colitis (LC). Clinical history, including alcohol and smoking status at the time of diagnosis of MC, were reviewed. In this case-control study, age- and gender-matched patients without diarrhea presenting for outpatient colonoscopy served as the control population.
  
  
  RESULTS
  We analyzed a total of 340 patients with MC: 124 with CC and 216 with LC. Overall, any smoking status (former or current) was associated with MC (odds ratio [OR] 2.12, 95% confidence interval [CI]: 1.56-2.88). This risk was more prominent in current smokers (adjusted OR 5.36, 3.81, and 4.37 for CC, LC, and all MC, respectively, 95% CI all greater than 1). The association of smoking was not significantly affected by gender or average alcohol consumption.
  
  
  CONCLUSIONS
  In our study population, cigarette smoking is a risk factor for the development of both forms of microscopic colitis. There were no significant differences between LC and CC, and current smoking and the development of microscopic colitis affected men and women similarly. We feel that these data are sufficient to discuss the potential risks of tobacco use in patients with microscopic colitis.
authors.affiliation: Division of Gastroenterology, University of Chicago, Pritzker School of Medicine, NorthShore University HealthSystem, Evanston, Illinois 60201, USA. eyen@uchicago.edu
authors.forename: Eugene F
authors.initials: EF
authors.lastname: Yen
authors.forename: Bhupesh
authors.initials: B
authors.lastname: Pokhrel
authors.forename: Hongyan
authors.initials: H
authors.lastname: Du
authors.forename: Steven
authors.initials: S
authors.lastname: Nwe
authors.forename: Laura
authors.initials: L
authors.lastname: Bianchi
authors.forename: Benjamin
authors.initials: B
authors.lastname: Witt
authors.forename: Curtis
authors.initials: C
authors.lastname: Hall
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D046729:Colitis, Collagenous / Q000209:etiology* / Q000473:pathology; D046730:Colitis, Lymphocytic / Q000209:etiology* / Q000473:pathology; D046728:Colitis, Microscopic / Q000209:etiology* / Q000473:pathology; D003113:Colonoscopy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D011379:Prognosis; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects*