The epidemiology and phenotype of Crohn's disease in the Chinese population

Background: Inflammatory bowel disease is uncommon in Southeast Asia but is increasing in incidence. The epidemiology and phenotype of Crohn disease (CD) in the Chinese population is not well-known. The purpose of this study was to determine the incidence, temporal trend, clinical features, risk factors, extraintestinal manifestations, and the treatment of CD in the Chinese population of Hong Kong. Methods: We performed a single-center study of consecutive definite CD cases based on internationally accepted criteria, with strict exclusion of infective enterocolitis. Results: Eighty Chinese CD patients were recruited, characterized by male gender predominance (male:female ratio 2.5:1), no association with ever smoking (OR 1.02, 95% CI: 0.54-1.92), absence of familial clustering (0%), high proportion of upper gastrointestinal tract disease proximal to the terminal ileum (19%), and a low proportion of isolated terminal ileal disease (4%). The mean age at diagnosis was 33 years. Forty-five percent of patients had penetrating disease, 18% stricturing disease, and 37% bad nonstricturing, nonpenetrating disease. Twenty-five percent of patients had at least 1 extraintestinal manifestation, and there was a high rate of ankylosing spondylitis (9%). The incidence of CD was 1.0 per 100,000 and has increased by 3 fold during the past decade. The age-adjusted incidence was 3.0 per 100,000 (95% CI: 2.3-3.7 per 100,000). Conclusions: The incidence of CD in the Chinese is increasing. There are some notable epidemiological and phenotypic differences between Chinese CD with Caucasian CD including the lack of familial clustering, male predominance, and higher proportion of upper GIT involvement and lower frequency of isolated terminal ileal disease.