Epidemiology, Natural History, and Risk Stratification of Crohn's Disease.

Crohn's disease (CD) is a chronic condition that can result in significant morbidity and disability. By studying the association between demographics and initial clinical features and subsequent natural history, one may be able to stratify patients by their risks of clinical relapse, hospitalization, and surgery. Understanding the potential environmental risk factors and natural history of CD in a given patient guides the physician when counseling the patient and selecting a treatment strategy. In this review, updated data regarding the incidence and prevalence of CD, important environmental risk factors, natural history of the disease, and important prognostic factors are discussed.