title: Crohn's disease in mainland China: a systematic analysis of 50 years of research.
abstract: BACKGROUND
  Crohn's disease appears to be increasing in frequency in many areas of the world. However, little information with regard to disease incidence, prevalence and temporal trends has been published in China.
  
  
  OBJECTIVE
  The aim of this review is to better understand the occurrence of Crohn's disease in mainland China, and to give an overview of the current status of the disease.
  
  
  METHODS
  We used a computer-based literature search using 50-years of records from the Chinese Database of Biology and Medicine (CBM, 1979-2002), combined with a manual year-by-year search of the literature from 1950 to 1979. Each article was double-reviewed, and all descriptive epidemiological data were recorded, pooled and statistically analyzed.
  
  
  RESULTS
  In total, 1526 cases of Crohn's disease since 1950 have been reported by more than 50 hospitals from 22 provinces and cities in mainland China, comprising 884 male and 642 female patients, with a 1.38:1 male predominance. More than 70% of patients were aged 20 to 50 years old, with a mean age of 37.2 +/- 2.68 (ranging from 1 to 83) years. The extrapolated disease incidence and prevalence rates are 0.28/100,000 person years and 1.38/100,000 persons, respectively.
  
  
  CONCLUSIONS
  The incidence and prevalence rates of Crohn's disease are still lower than those in Western and other Asian countries, but these rates have been increasing rapidly, and the disease is no longer uncommon. An underestimation may occur because the patients who were misdiagnosed or did not seek medical advice could not be included in the study. A future population-based survey is warranted.
authors.affiliation: Suzhou Institute for Digestive Disease and Nutrition, Suzhou University, Suzhou, China. zhengjj2218@163.com
authors.forename: Jia Ju
authors.initials: JJ
authors.lastname: Zheng
authors.forename: Xia Shuang
authors.initials: XS
authors.lastname: Zhu
authors.forename: Zhao
authors.initials: Z
authors.lastname: Huangfu
authors.forename: Zhi Xin
authors.initials: ZX
authors.lastname: Gao
authors.forename: Zhi Rong
authors.initials: ZR
authors.lastname: Guo
authors.forename: Zhen
authors.initials: Z
authors.lastname: Wang
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D002681:China / Q000453:epidemiology; D003424:Crohn Disease / Q000453:epidemiology*; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D008297:Male; D008875:Middle Aged; D015995:Prevalence