Context

Smoking is the most well-studied environmental risk factor of inflammatory bowel diseases (IBDs). Ulcerative colitis is less prevalent in smokers and the converse is true for Crohn's disease (CD). Smoking has a detrimental effect on the course of CD including worse disease course, increased need for surgery, more frequent need for maintenance medications and higher need for biological agents.1–3 Smokers were found to have a significantly decreased survival free of stricturing disease or perianal complications, and had a higher rate of thiopurine therapy requirement.4 The benefit of smoking cessation on CD was …