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.
Article first published online 2 April 2013
1Department of Gastroenterology, Hospital Universitari Mutua Terrassa, Terrassa, Spain;
2Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Spain;
3Department of Gastroenterology, Hospital San Jorge, Huesca, Spain;
4Department of Pathology, Hospital Universitari Mutua Terrassa, Terrassa, Spain;
5Department of Gastroenterology, Hospital La Fe, Valencia, Spain;
6Department of Gastroenterology, Consorci Sanitari de Terrassa, Terrassa, Spain;
7Department of Gastroenterology, Hospital Reina Sofía, Córdoba, Spain;
8Department of Gastroenterology, Hospital La Princesa, Madrid, Spain;
9Department of Gastroenterology, Hospital Vall d'Hebron, Barcelona, Spain;
10Department of Gastroenterology, Hospital Parc Taulí, Sabadell, Spain;
11Department of Gastroenterology, Hospital Sant Pau, Barcelona, Spain;
12Department of Gastroenterology, Hospital Clinic, Barcelona, Spain;
13Department of Gastroenterology, Hospital del Mar, Barcelona, Spain; and
14Department of Gastroenterology, Hospital Infanta Cristina, Madrid, Spain.
Reprints: Fernando Fernández-Bañares, MD, PhD, Department of Gastroenterology, Hospital Universitari Mutua Terrassa, University of Barcelona, Plaza Dr Robert 5, Terrassa 08221, Spain (e-mail: firstname.lastname@example.org).
Supported by a grant from the Instituto de Salud Carlos III (PI061577, Spain), and by Dr Falk Pharma Spain and Faes Farma Spain. These sponsors had no role in the study design, in the acquisition, analysis, or interpretation of the data or the writing of the report.
The authors have no conflicts of interest to disclose.
Received October 03, 2012
Accepted October 04, 2012