Reviewed by: HU Medical Review Board | Last Reviewed: January 2018.

Inflammatory bowel disease (IBD), which encompasses both Crohn’s disease (CD) and ulcerative colitis (UC), is a condition in which inflammation of the digestive tract causes a range of different symptoms and complications, such as diarrhea, abdominal pain and fatigue.

What is the relationship between smoking and inflammatory bowel disease?

Smoking is one of the most well studied environmental trigger in IBD. There is a large amount of scientific evidence to suggest that there is a relationship between smoking and CD.1-3 For example, studies have shown that:

  • Current smokers are twice as likely to develop CD as people who have never smoked
  • Smoking increases the frequency of symptom flare ups
  • Some CD medications become less effective if a patient continues smoking
  • Smoking can increase the likelihood of need for surgical treatment for CD

However, there seems to be an inverse relationship between smoking and UC. That is, smoking is associated with a lower risk and less severe disease in people with UC. Several studies have found that active smokers are less likely to have ulcerative colitis than people who have never smoked, but the exact mechanism of how smoking affects the development of IBD isn’t clear.1,4,5

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Most people are aware of the many health consequences of smoking and the many benefits of quitting, whether or not you have IBD. Research has shown that people with CD who stop smoking tend to experience fewer flare-ups and are less likely to need treatment with corticosteroids. For those with UC, while it may be tempting to continue smoking to reduce the severity of the disease, smoking increases the risk of several other diseases, including heart disease, lung cancer, and other cancers.2

What are some strategies to help people with IBD to quit smoking?

Quitting smoking can be a very difficult process, because cigarettes contain a highly addictive chemical called nicotine. For people with IBD, quitting smoking can be particularly difficult: abruptly quitting smoking may cause a flare up in symptoms. The stress of symptom flare ups can then make a patient want to reach for a cigarette as a way to relieve the symptom-related stress. This is why it is important to consult your healthcare provider before deciding to quit smoking “cold-turkey,” or all at once.3

Even though it may be difficult, quitting smoking is a critically important step to take. Some doctors may prescribe people with IBD with a medication called Zyban to help them quit smoking. Zyban contains bupropion, an antidepressant that has proven to help some patients give up smoking. Some side effects of bupropion include:

  • Dry mouth
  • Nausea
  • Weight loss

Before taking any medications, it is best to discuss with your doctor any possible side effects or drug interactions. Your doctor may recommend you to see a smoking cessation specialist, or someone who specializes in helping people quit smoking.

The health issues caused by smoking have been common knowledge in recent decades. Quitting smoking may be difficult but it will greatly improve quality of life in the long term. Don’t be afraid to ask for help and support from family and friends.