The Effect of Smoking on the Crohn's Disease

Crohn's disease is a autoimmune,chronic and inflammatory bowel disease.In the past decade, the incidence of CD grew fast around the world including China. The precise etiology and the pathogenic mechanisms of CD remains obscure, however, it is considered to be induced by the environment factors and heritable factors together. Smoking is not only a risk factor for Crohn's disease, but ongoing smoking is associated with a poor disease course. Patients who smoke are likely to develop the complex complications, increase the dose and frequency of immune inhabitation , and have higher risk of postoperative recurrence. Smoking cessation is associated with a much reduction in the risk of relapse as compared with continued smokers, unequivocally improves the course of Crohn's disease. The article aims to offer the past two decades reviews of the effects of smoking on Crohn's disease, to make more people know the relationship between them, and to encourage the patients to try to quit smoking, improve the disease course.