title: Emerging leadership lecture: Inflammatory bowel disease in Asia: emergence of a "Western" disease.
abstract: More than a decade ago, inflammatory bowel disease (IBD) is rare in Asia. Today, the importance of IBD in Asia is exemplified by its rapidly increasing incidence, complicated disease behavior, and substantial morbidity. In the first large-scale population-based epidemiologic study in Asia, 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 Asia. Ulcerative colitis (UC) is more prevalent than Crohn's disease (CD), although CD incidence is rapidly increasing. A positive family history is much less common than in the West, as are extra-intestinal disease manifestations. Complicated and penetrating CD are common in Asia. These epidemiologic changes may relate to increased contact with the West, westernization of diet, improved hygiene, increasing antibiotics use, or changes in the gut microbiota. Asian patients with CD have altered gut microbiota compared with their healthy counterparts and Caucasian 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 Asians and Caucasians. 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 East Asians. Research in Asia, an area of rapidly changing IBD epidemiology, may lead to the discovery of critical etiologic factors that lead to the development of IBD.
authors.affiliation: Department of Medicine and Therapeutics, Institute of Digestive Disease, State Key Laboratory of Digestive Diseases, Chinese University of Hong Kong, Hong Kong.
authors.forename: Siew C
authors.initials: SC
authors.lastname: Ng
mesh_terms: D001208:Asia / Q000453:epidemiology; D001343:Autophagy / Q000235:genetics; D001942:Breast Feeding; D016022:Case-Control Studies; D003093:Colitis, Ulcerative / Q000453:epidemiology / Q000209:etiology; D003424:Crohn Disease / Q000453:epidemiology / Q000209:etiology; D004073:Digitoxigenin / Q000031:analogs & derivatives; D004777:Environment; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000453:epidemiology* / Q000209:etiology; D007413:Intestinal Mucosa / Q000382:microbiology; D053473:Nod2 Signaling Adaptor Protein / Q000235:genetics; D057805:Pets; D011110:Polymorphism, Genetic; D053380:Tumor Necrosis Factor Ligand Superfamily Member 15 / Q000235:genetics
chemical_list: C504216:INCICH-D7; C429018:NOD2 protein, human; D053473:Nod2 Signaling Adaptor Protein; C117026:TNFSF15 protein, human; D053380:Tumor Necrosis Factor Ligand Superfamily Member 15; D004073:Digitoxigenin
keywords: IBD; epidemiology; genetics; risk factors