Inflammatory bowel disease: Epidemiology, pathogenesis, and therapeutic opportunities

Ulcerative colitis (UC) and Crohn's disease (CD), the primary constituents of inflammatory bowel disease (IBD), are precipitated by a complex interaction of environmental, genetic, and immunoregulatory factors. Higher rates of IBD are seen in northern, industrialized countries, with greater prevalence among Caucasians and Ashkenazic Jews. Racial gaps are closing, indicating that environmental factors may play a role. IBD is multigenic, with the most clearly established genetic link between certain NOD2 variants and CD. Regardless of the underlying genetic predisposition, a growing body of data implicates a dysfunctional mucosal immune response to commensal bacteria in the pathogenesis of IBD, especially CD.…