Emergence of inflammatory bowel disease 'beyond the West': do prosperity and improved hygiene have a role?

Inflammatory bowel disease (IBD) is increasing in many countries 'beyond the West'. This increase may be due to an increased rate of diagnosis but might also represent a true increase in incidence. Economic development, leading to improved hygiene and other changes in lifestyle, may play a role in the increase in IBD. However, the marked difference in prevalence between ethnic groups suggests that the genetic background of populations may also be relevant and supports the current hypothesis that IBD represents an interaction between environmental factors and a genetically susceptible host. Investigating the early stages of IBD as it emerges in new populations may provide new clues to its pathophysiology.