IBD and Smoking

Plenty of research studies show the connections between cigarette smoking and inflammatory bowel disease, but a key mystery has yet to be solved. Among Crohn's disease patients, smokers have a poorer disease course than those who don't smoke (1, 2). Yet, with ulcerative colitis, smoking seems somehow protective (1). Surprisingly, the ulcerative colitis patients with more complaints and more relapses are the non-smokers (2). These opposite effects can cause confusion when it comes to advising patients about quitting.

Smoking and Crohn's Disease

Smokers have at least twice the risk of developing Crohn's disease as non-smokers (2, 3). Once they have it, patients who smoke usually have a more severe form of Crohn's (2).

  • In a 6-month study, the relapse rate for smokers was 34% higher than for non-smoking patients (2).
  • Another study showed that of 174 patients, smokers needed repeat surgery more often than non-smokers (4).
  • Smokers are more likely than non-smokers to need steroids and immunosuppressive therapy (1, 5).

A study of 59 smokers with Crohn's disease shows that quitting can indeed make a difference. Those who stopped for more than a year had 65% lower risk of flare-up than continued smokers (6). Smoking cessation should clearly be a primary therapeutic goal in the treatment of Crohn's disease (6).

Smoking and Ulcerative Colitis

For patients with ulcerative colitis, smoking has quite the opposite effect. Many studies show that this is largely a disease of non-smokers (2).

  • Patients who never smoked, or who quit, have a greater risk of developing ulcerative colitis than current smokers do (2);
  • Patients who never smoked, but then start smoking after diagnosis, have less frequent clinical relapses (2, 7);
  • Smokers who quit are later twice as likely as current smokers to require colectomy (1).

Physicians should educate patients about the association between smoking and smoking cessation and ulcerative colitis to help them make an informed decision in the management of their disease and other health concerns (2).

This information is intended for healthcare professionals only.


References

  1. Hanauer, S. (2006). Inflammatory Bowel Disease: Epidemiology, Pathogenesis, and Therapeutic Opportunities. Inflammatory Bowel Disease 12: S3-S9. Available at: http://www.ccfaprofessionals.org/atf/cf/%7B9BC60EE0-BE90-4E6E-8FAF-801B99E0F97F%7D/
    IBD%20-%20Epidemiology,%20Pathogenesis,%20and%20Therapeutic%20Opportunites.pdf. Accessed June 23, 2006.
  2. Thomas, G., Rhodes, J., Green, J. & Richardson, C. (2000). Role of smoking in inflammatory bowel disease: implications for therapy. Postgraduate Medical Journal. 2000; 76; 273-279. Available at: http://pmj.bmjjournals.com/cgi/reprint/76/895/273. Accessed June 24, 2006.
  3. National Association for Colitis and Crohn's Disease (November 2005). Smoking and IBD Information Sheet. Available at: http://www.nacc.org.uk/content/services/infoSheets.asp. Accessed June 23, 2006.
  4. Sutherland, L.R., Ramcharan, S., Bryant, H., & Fick, G. (1990). Effect of cigarette smoking on recurrence of Crohn's disease. Gastroenterology 98: 1123-8. Available at: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi? db=pubmed&cmd=Retrieve&
    dopt=Abstract&list_uids=2323505&query_hl=4&itool=pubmed_docsum. Accessed June 25, 2006.
  5. Cosnes, J., Beaugerie, L., Carbonnel, F., and Gendre, J. (2000). Smoking cessation and the course of Crohn's disease: An intervention study. Gastroenterology, 120(5), 1093-1099. Available at: http://www.gastrojournal.org/article/PIIS0016508501577690/abstract. Accessed August 10, 2006.
  6. Johnson, G. J., Cosnes, J., & Mansfield, J. C. (2005). Review article: smoking cessation as primary therapy to modify the course of Crohn's disease. Alimentary Pharmacology & Therapeutics 21 (8) 921-931. Available at: http://www.blackwell-synergy.com/doi/abs/10.1111/j.
    1365-2036.2005.02424.x. Accessed June 23, 2006.
  7. Fraga, X.F., Vergara, M., Medina, C., Casellas, F., Bermejo, B., & Malagelada, M.R. (1997). Effects of smoking on the presentation and clinical course of inflammatory bowel disease. European Journal of Gastroenterology & Hepatology, 9 (7):683-7. Available at: http://www.ncbi.nlm.nih.gov/
    entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9262977&dopt=Abstract. Accessed June 21, 2006.
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