This review aimed to summarize the epidemiology (incidence, prevalence and morality) and risk factors of inflammatory bowel disease (IBD). IBD is a chronic, relapsing, inflammatory disorder of the gastrointestinal tract and includes Crohn's Disease (CD) and ulcerative colitis (UC). IBD has increasing incidence and prevalence in most of countries and becomes a global emerging disease. A westernized lifestyle or habits and some environmental factors have been found to contribute to the pathogenesis of IBD. The relevant risk factors include Smoking, hygiene hypothesis, microorganisms, appendectomy, medication, nutrition, and stress have all been found to be associated with the modality of IBD, but results are inconsistent on this issue in available studies. Therefore, more studies are required to identify and understand the environmental determinants of IBD.
Keywords: Incidence; environmental factors; inflammatory bowel disease; morality; prevalence.