Smoking and IBD

Why is smoking considered bad for us?

During smoking tobacco breaks down and generates more than 7,000 toxic compounds and so far, more than 60 carcinogenic compounds have been identified in cigarette smoke (1).

In addition to the increase risk cancers and cardiovascular disease, smoking can directly impact the health of our digestive system by altering the mucus produced in our large intestine, altering the balance of bacteria – increasing some proinflammatory species and decreasing some healthful species, increasing the permeability of our intestinal lining, and changes in our immune system which can increase inflammation. It can also put extra stress and toxic load on our body that is already working very hard and often struggling anyway when we have IBD.

However, cigarette smoking can affect symptoms and disease course of Crohn’s Disease and Ulcerative Colitis very differently.

 

Crohn’s disease and smoking

Smoking can increase a person’s risk of developing Crohn’s disease (2) and when you have Crohn’s smoking can make the disease experience worse (1).

Smoking with Crohn’s may worsen symptoms, increase the number of flare-ups the person experiences, reduce response to treatment and decrease quality of life. In the longer term, it may lead to more complications like strictures (narrowing of the bowel), higher rate of hospitalisation and increase risk of surgery (1).

The good news is that the impact of cigarette smoking on Crohn’s Disease is temporary, and if you give up smoking, the course of the disease can improve and about 2 years after stopping the impact of smoking on the disease is the same as those with Crohn’s who have never smoked (3).

 

Ulcerative Colitis and smoking

In ulcerative colitis, smoking seems to have the opposite effect.

The risk of developing UC seems to be higher in non-smokers compared to people who smoke (2). Some research has shown that current smokers with UC may have milder symptoms, may require less steroid therapy than non-smokers and flare up (4). Although hospitalisation and colectomy rates seem to be similar in smokers versus non-smokers (5), and there is some evidence that eye, joint and skin problems may be worse in smokers with UC (6, 7).

It is not completely clear why smoking might have this impact in colitis but its been suggested that nicotine in cigarettes may alter the way genes are expressed, mucus production in the colon and could suppress immune function (1, 4).

There have been some trials in the use of nicotine in various forms (chewing gum, transdermal patches, and nicotine-based enemas) as a treatment for UC but results are inconclusive (1) and although nicotine patches may have shown some benefit for UC in trials, nicotine treatment has not been shown to be more effective than conventional drug treatment and it has limited use in patients due to its side effects such as acute pancreatitis, headache, nausea, tremor and sleep disturbance (8).

Take Away Points

  • Smoking seems to worsen Crohn’s Disease but giving up smoking can improve the symptoms worsened by smoking.

  • Smoking may be protective in UC but treatment of UC with cigarettes and nicotine is so far inconclusive and has not been shown to be more effective than conventional treatments. At the moment, the risks and side effects of smoking or nicotine treatment in UC seem to outweigh the benefits.

  • Given the huge number of other negative impacts smoking can have on our health (increased risk of cancer, including bowel, lung, stomach and ovarian, and 2-fold increased risk of heart attack), even if you have UC smoking cessation is advised. If you have colitis and want to give up smoking please speak with your IBD team so they can support you through it should you need it.

If you want to get help Crohn’s and Colitis UK have some great information here and the NHS here.

 

References

  1. Berkowitz, L., Schultz, B., Salazar, G., Pardo-Roa, C., Sebastián, V., Álvarez-Lobos, M., Bueno, S., (2018) Impact of Cigarette Smoking on the Gastrointestinal Tract Inflammation: Opposing Effects in Crohn’s Disease and Ulcerative Colitis. Frontiers in Immunology. 9. 74. https://www.frontiersin.org/article/10.3389/fimmu.2018.00074    

  2. Calkins BM. A meta-analysis of the role of smoking in inflammatory bowel disease. Dig Dis Sci (1989) 34:1841–54. doi:10.1007/BF01536701

  3. Cosnes J, Beaugerie L, Carbonnel F, Gendre JP. Smoking cessation and the course of Crohn’s disease: an intervention study. Gastroenterology (2001) 120:1093–9. doi:10.1053/gast.2001.23231

  4. Crohns and Colitis UK. 2021. Smoking and IBD. [ONLINE] Available at: https://www.crohnsandcolitis.org.uk/about-crohns-and colitis/publications/smoking-and ibd#:~:text=Many%20studies%20have%20shown%20that,carries%20many%20other%20health%20risks.. [Accessed 22 February 2021].

  5. Lunney P et al. Smoking prevalence and its influence on disease course and surgery in Crohn’s disease and ulcerative colitis. Alimentary Pharmacology and Therapeutics. 2015;42(1):61-70.

  6. AlQasrawi, Dania; Abdelli, Latifa S.; Naser, Saleh A. 2020. "Mystery Solved: Why Smoke Extract Worsens Disease in Smokers with Crohn’s Disease and Not Ulcerative Colitis? Gut MAP!" Microorganisms 8, no. 5: 666. https://doi.org/10.3390/microorganisms8050666

  7. Roberts H et al. Extraintestinal manifestations of inflammatory bowel disease and the influence of smoking. Digestion. 2014;90(2):122-129.

  8. Sandborn WJ, Tremaine WJ, Leighton JA, Lawson GM, Zins BJ, Compton RF, et al. Nicotine tartrate liquid enemas for mildly to moderately active left-sided ulcerative colitis unresponsive to first-line therapy: a pilot study. Aliment Pharmacol Ther (1997) 11:663–71.

 

Clemmie Macpherson