Abstract

A lasting lesson for gastroenterologists was the failure of traditional epidemiologic approaches to raise the possibility of a transmissible agent as a cause of peptic ulcer disease. Another lesson was that the solution to some human disorders can never be found by reliance on research focused exclusively on the human host, without due reference to the interface with the microbial environment. In the case of inflammatory bowel diseases (IBD), excessive reliance on conventional risk factor epidemiology without adequate rapprochement with concepts of disease mechanisms is likely to provide more controversy, conflict and confusion than consensus. However, the changing epidemiology of IBD associated with societal transition from developing to developed status is of such consistency that it represents a model, and may facilitate reconciling disparate lifestyle and environmental factors with causal mechanisms.