Inflammatory Bowel Disease: Epidemiology

Inflammatory bowel disease (IBD) is characterized by two partially distinct alimentary disease processes, namely Crohn’s disease (CD) and ulcerative colitis (UC), affecting genetically predisposed individuals. CD and UC were first described in 1932 and 1859, respectively. It is estimated that 1.5 million in North America and 2.5 million persons in Europe have IBD. The peak incidence of CD and UC is between 20–30 years and 30–40 years of age, respectively. Both incidence and prevalence of CD and UC are similar across males and females. However, several studies suggest a female predominance in CD and a male predominance in UC. The pathogenesis of IBD is attributed to an uncontrolled immune-mediated inflammatory response to an unrecognized environmental trigger that interacts with the intestinal flora. Various determinants of IBD include the following: peculiar environmental triggers, intestinal immune mechanisms, heritable factors, gut flora, diet, mesenteric fat, medications, nicotine, infectious agents, immunization, hygiene, pregnancy, breastfeeding, stress and lifestyle. Predominant complications in IBD are surgery, malnutrition, disease exacerbations and cancer. Patients with CD have a higher mortality compared to general population. Epidemiological studies continue to expand our understanding of the distribution, determinants and mechanisms of IBD. This has enabled us to recognize safer and effective approaches to management.