Inflammatory bowel disease and environmental influences

The dramatic emergence of IBD over the past century, particularly in the industrialized countries of Europe and North America, implicates a strong environmental influence in the development of Crohn's disease and ulcerative colitis. An extensive array of factors has been investigated, ranging from diet and tobacco to occupation and toothpaste. In recent years, the peculiar relationship between smoking and IBD has been clarified with divergent influences in the two diseases: protective in ulcerative colitis, while harmful in Crohn's disease. New research has established appendectomy as a potent protective factor against the development of ulcerative colitis. Numerous other issues, such as breast feeding, sanitation, oral contraceptives, and refined sugar intake, remain less well defined and controversial. This article summarizes the extensive investigation of complex interactions between the environment and IBD.