Emerging leadership lecture: Inflammatory bowel disease in A sia: Emergence of a “ W estern” disease

More than a decade ago, inflammatory bowel disease ( IBD ) is rare in A sia. Today, the importance of IBD in A sia is exemplified by its rapidly increasing incidence, complicated disease behavior, and substantial morbidity. In the first large‐scale population‐based epidemiologic study in A sia, the incidence of IBD varied from 0.60 to 3.44 per 100 000. There has been a twofold to threefold increase in the incidence of IBD in several countries in A sia. Ulcerative colitis ( UC ) is more prevalent than C rohn's disease ( CD ), although CD incidence is rapidly increasing. A positive family history is much less common than in the W est, as are extra‐intestinal disease manifestations. Complicated and penetrating CD are common in A sia. These epidemiologic changes may relate to increased contact with the W est, westernization of diet, improved hygiene, increasing antibiotics use, or changes in the gut microbiota. A sian patients with CD have altered gut microbiota compared with their healthy counterparts and C aucasian CD subjects. Mucosa‐associated microbiota in IBD may differ geographically. In a population‐based case–control study, breast‐feeding, having pets, and better sanitary conditions were protective of IBD , suggesting that childhood environment plays an important role in modulating disease development. Genetic factors also differ between A sians and C aucasians. Nucleotide oligomerization domain‐2 ( NOD2 ) and autophagy variants were not associated with CD , but tumor necrosis factor superfamily gene‐15 polymorphisms were strongly associated with CD in E ast A sians. Research in A sia, an area of rapidly changing IBD epidemiology, may lead to the discovery of critical etiologic factors that lead to the development of IBD .