Impact of Smoking Cessation on the Clinical Course of Crohn's Disease Under Current Therapeutic Algorithms: A Multicenter Prospective Study

Am J Gastroenterol. 2016 Mar;111(3):411-9. doi: 10.1038/ajg.2015.401. Epub 2016 Feb 9.


Objectives: Given the importance of tobacco smoking (TS) as the only environmental factor repeatedly linked to the development of the Crohn's disease (CD), it is surprising that very few prospective studies have assessed whether TS is associated with an increased frequency of clinical relapse. Our aim was to evaluate the current impact of TS on disease relapse and the clinical benefit of quitting smoking in the present era of widespread use of anti-TNF drugs and immunosuppressants.

Methods: This was a multicenter prospective cohort study, which included 573 CD patients in clinical remission with various smoking habits. All smokers were advised to quit. Patients not exposed to tobacco before inclusion (non- and former smokers), continuing smokers, and quitters were compared regarding differences in disease outcomes during a follow-up of 4 years.

Results: A total of 148 continuing smokers, 190 nonsmokers, 160 former smokers, and 75 quitters were included. In comparison with nonsmokers, continuing smokers relapsed more frequently with an incidence rate ratio of 1.53 (95% confidence interval (CI): 1.10-2.17). Former smokers and quitters had similar relapse incidences compared with nonsmokers. Smoking was an independent predictor for disease relapse in the multivariate analysis (hazard ratio: 1.58 (95% CI 1.20-2.09). In the time-dependent analysis, continuing smokers had earlier relapse, regardless of anti-TNF or immunosuppressant use.

Conclusions: Continuing smokers have more disease relapses, and patients who quit smoking have a similar relapse incidence compared with nonsmokers.

Publication types

  • Multicenter Study
  • Observational Study

MeSH terms

  • Adult
  • Algorithms
  • Anti-Inflammatory Agents / therapeutic use
  • Cohort Studies
  • Confidence Intervals
  • Crohn Disease* / drug therapy
  • Crohn Disease* / epidemiology
  • Crohn Disease* / psychology
  • Female
  • Humans
  • Immunosuppressive Agents / therapeutic use*
  • Male
  • Middle Aged
  • Prospective Studies
  • Recurrence
  • Risk Factors
  • Secondary Prevention / methods
  • Secondary Prevention / statistics & numerical data
  • Smoking Cessation / statistics & numerical data*
  • Smoking* / adverse effects
  • Smoking* / epidemiology
  • Smoking* / physiopathology
  • Spain / epidemiology
  • Tumor Necrosis Factor-alpha / antagonists & inhibitors*


  • Anti-Inflammatory Agents
  • Immunosuppressive Agents
  • Tumor Necrosis Factor-alpha