title: Impact of current smoking on the clinical course of microscopic colitis.
abstract: BACKGROUND
  Whether current smoking worsens the clinical course of microscopic colitis (MC) is unknown. The aim was to evaluate the impact of smoking on the clinical course of MC.
  
  
  METHODS
  One hundred and eighty-four patients (72% women; age, 62.4 ± 1.1 years) with MC (118 collagenous colitis (CC) and 66 lymphocytic colitis (LC) were evaluated (39 of them were current smokers). In all the patients, smoking habits and clinical data at presentation, response to therapy, and clinical relapses during follow-up were prospectively recorded. Risk factors for clinical relapse were studied in 160 patients after a mean follow-up of 28 ± 1 months. Cox regression analysis was used to adjust for confounding variables.
  
  
  RESULTS
  Age at diarrhea onset was 63.0 ± 1.4 years in nonsmokers and 50.4 ± 2.1 years in current smokers (P < 0.001). There was no significant influence of smoking habit on either clinical symptoms at diagnosis or clinical remission rate. Clinical relapse rate was 25.5% for CC and 29.6% for LC, with the mean relapse-free time 28.8 months (95% confidence interval, 26.3-31.4) for CC and 26.9 months (95% confidence interval, 26-30.3) for LC (P = 0.5). Multivariate analysis showed that age at diagnosis (<50 years versus others; adjusted hazard ratio, 2.8; 95% confidence interval, 1.3-6; P = 0.01) was associated with risk of relapse of CC but not LC. Current smoking was not an independent risk factor for either CC or LC relapse.
  
  
  CONCLUSIONS
  Active smokers developed MC more than a decade before nonsmokers. Age at diagnosis, but not smoking, was an independent risk factor of relapse in patients with CC.
authors.affiliation: Department of Gastroenterology, Hospital Universitari Mutua Terrassa, Terrassa, Spain. ffbanares@mutuaterrassa.es
authors.forename: Fernando
authors.initials: F
authors.lastname: Fernández-Bañares
authors.forename: Monia R
authors.initials: MR
authors.lastname: de Sousa
authors.forename: Antonio
authors.initials: A
authors.lastname: Salas
authors.forename: Belén
authors.initials: B
authors.lastname: Beltrán
authors.forename: Marta
authors.initials: M
authors.lastname: Piqueras
authors.forename: Eva
authors.initials: E
authors.lastname: Iglesias
authors.forename: Javier P
authors.initials: JP
authors.lastname: Gisbert
authors.forename: Beatriz
authors.initials: B
authors.lastname: Lobo
authors.forename: Valentí
authors.initials: V
authors.lastname: Puig-Diví
authors.forename: Esther
authors.initials: E
authors.lastname: García-Planella
authors.forename: Ingrid
authors.initials: I
authors.lastname: Ordás
authors.forename: Montserrat
authors.initials: M
authors.lastname: Andreu
authors.forename: Marta
authors.initials: M
authors.lastname: Calvo
authors.forename: Miguel
authors.initials: M
authors.lastname: Montoro
authors.forename: Maria
authors.initials: M
authors.lastname: Esteve
authors.forename: Josep M
authors.initials: JM
authors.lastname: Viver
mesh_terms: D000368:Aged; D046729:Colitis, Collagenous / Q000209:etiology* / Q000473:pathology / Q000628:therapy; D046730:Colitis, Lymphocytic / Q000209:etiology* / Q000473:pathology / Q000628:therapy; D046728:Colitis, Microscopic / Q000209:etiology* / Q000473:pathology / Q000628:therapy; D003113:Colonoscopy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies; D012008:Recurrence; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects*