title: Incidence and phenotype of inflammatory bowel disease based on results from the Asia-pacific Crohn's and colitis epidemiology study.
abstract: OBJECTIVE
  Inflammatory bowel diseases (IBD) are becoming more common in Asia, but epidemiologic data are lacking. The Asia-Pacific Crohn's and Colitis Epidemiology Study aimed to determine the incidence and phenotype of IBD in 8 countries across Asia and in Australia.
  
  
  METHODS
  We performed a prospective, population-based study of IBD incidence in predefined catchment areas, collecting data for 1 year, starting on April 1, 2011. New cases were ascertained from multiple overlapping sources and entered into a Web-based database. Cases were confirmed using standard criteria. Local endoscopy, pathology, and pharmacy records were searched to ensure completeness of case capture.
  
  
  RESULTS
  We identified 419 new cases of IBD (232 of ulcerative colitis [UC], 166 of Crohn's disease [CD], and 21 IBD-undetermined). The crude annual overall incidence values per 100,000 individuals were 1.37 for IBD in Asia (95% confidence interval: 1.25-1.51; 0.76 for UC, 0.54 for CD, and 0.07 for IBD-undetermined) and 23.67 in Australia (95% confidence interval: 18.46-29.85; 7.33 for UC, 14.00 for CD, and 2.33 for IBD-undetermined). China had the highest incidence of IBD in Asia (3.44 per 100,000 individuals). The ratios of UC to CD were 2.0 in Asia and 0.5 in Australia. Median time from symptom onset to diagnosis was 5.5 months (interquartile range, 1.4-15 months). Complicated CD (stricturing, penetrating, or perianal disease) was more common in Asia than Australia (52% vs 24%; P = .001), and a family history of IBD was less common in Asia (3% vs 17%; P < .001).
  
  
  CONCLUSIONS
  We performed a large-scale population-based study and found that although the incidence of IBD varies throughout Asia, it is still lower than in the West. IBD can be as severe or more severe in Asia than in the West. The emergence of IBD in Asia will result in the need for specific health care resources, and offers a unique opportunity to study etiologic factors in developing nations.
authors.affiliation: Institute of Digestive Disease, Department of Medicine and Therapeutics, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong, China. Electronic address: siewchienng@cuhk.edu.hk.
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authors.initials: SC
authors.lastname: Ng
authors.affiliation: Institute of Digestive Disease, Department of Medicine and Therapeutics, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong, China.
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authors.affiliation: Institute of Digestive Disease, Department of Medicine and Therapeutics, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong, China.
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authors.affiliation: Institute of Digestive Disease, Department of Medicine and Therapeutics, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong, China.
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authors.affiliation: Department of Pediatrics, Chinese University of Hong Kong, Hong Kong, China.
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authors.affiliation: Kiangwu Hospital, Macau, China.
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authors.affiliation: Kiangwu Hospital, Macau, China.
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authors.affiliation: Hospital Conde S Januario, Macau, China.
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authors.affiliation: St Vincent's Hospital and University of Melbourne, Melbourne, Australia.
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authors.affiliation: St Vincent's Hospital and University of Melbourne, Melbourne, Australia.
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authors.affiliation: St Vincent's Hospital and University of Melbourne, Melbourne, Australia.
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authors.affiliation: Faculty of Medicine, University of Kelaniya, Ragama, Sri Lanka.
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authors.affiliation: Faculty of Medicine, University of Kelaniya, Ragama, Sri Lanka.
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authors.affiliation: Faculty of Medicine, University of Kelaniya, Ragama, Sri Lanka.
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authors.affiliation: Singapore General Hospital, Singapore.
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authors.affiliation: Singapore General Hospital, Singapore.
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authors.affiliation: National University Hospital of Singapore, Singapore.
authors.forename: Poh Seng
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authors.lastname: Tan
authors.affiliation: National University Hospital of Singapore, Singapore.
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authors.lastname: Ong
authors.affiliation: University of Malaya Medical Centre, Kuala Lumpur, Malaysia.
authors.forename: Khean L
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authors.affiliation: University of Malaya Medical Centre, Kuala Lumpur, Malaysia.
authors.forename: Ida
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authors.affiliation: Maharaj Nakorn Chiangmai Hospital, Chiangmai, Thailand.
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authors.affiliation: Siriraj Hosptial, Bangkok, Thailand.
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authors.affiliation: King Chulalongkorn Memorial Hospital, Bangkok, Thailand.
authors.forename: Rungsun
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authors.affiliation: King Chulalongkorn Memorial Hospital, Bangkok, Thailand.
authors.forename: Satimai
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authors.lastname: Aniwan
authors.affiliation: West China Hospital, Sichuan University, Chengdu, China.
authors.forename: Yu Fang
authors.initials: YF
authors.lastname: Wang
authors.affiliation: West China Hospital, Sichuan University, Chengdu, China.
authors.forename: Qin
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authors.affiliation: The First Affiliated Hospital of San Yat Sen University, Guangzhou, China.
authors.forename: Zhirong
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authors.affiliation: The First Affiliated Hospital of San Yat Sen University, Guangzhou, China.
authors.forename: Zhenhua
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authors.lastname: Zhu
authors.affiliation: The First Affiliated Hospital of San Yat Sen University, Guangzhou, China.
authors.forename: Min Hu
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authors.lastname: Chen
authors.affiliation: The First Affiliated Hospital of San Yat Sen University, Guangzhou, China.
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authors.affiliation: Department of Gastroenterology, Xijing Hospital, Fourth Military Medical University, Shaanxi, China.
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authors.affiliation: Department of Gastroenterology, Xijing Hospital, Fourth Military Medical University, Shaanxi, China.
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authors.affiliation: University of Indonesia, Depok, Indonesia.
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authors.affiliation: University of Indonesia, Depok, Indonesia.
authors.forename: Murdani
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authors.affiliation: Institute of Digestive Disease, Department of Medicine and Therapeutics, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Justin Cy
authors.initials: JC
authors.lastname: Wu
authors.affiliation: Institute of Digestive Disease, Department of Medicine and Therapeutics, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Joseph J Y
authors.initials: JJY
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authors.affiliation: Institute of Digestive Disease, Department of Medicine and Therapeutics, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong, China.
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mesh_terms: D000328:Adult; D001208:Asia / Q000453:epidemiology; D001315:Australia / Q000453:epidemiology; D005260:Female; D006801:Humans; D015994:Incidence; D015212:Inflammatory Bowel Diseases / Q000175:diagnosis / Q000188:drug therapy / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D011446:Prospective Studies