title: Five-year risk of colorectal neoplasia after normal baseline colonoscopy in asymptomatic Chinese Mongolian over 50 years of age.
abstract: BACKGROUND
  After normal colonoscopy, the 5-year risk of colorectal neoplasia is sufficiently low for asymptomatic people over 50 years of age. In China, the incidence of colorectal carcinoma of Mongolian people is higher than that of Han people. The aim of this study was to assess the 5-year risk of colorectal neoplasia after normal colonoscopy in asymptomatic Chinese Mongolian population.
  
  
  METHODS
  A cohort of asymptomatic Chinese Mongolian people (≥50 years old) were recruited and followed up with colonoscopy 5 years after colonoscopy. Baseline colonoscopy and follow-up colonoscopy findings were categorized based on the most advanced lesions: no adenoma, nonadvanced adenoma, and advanced adenoma. Five-year risk of colorectal neoplasia in these people was assessed according to the rates of no baseline adenoma and advanced adenoma at the end of 5 years.
  
  
  RESULTS
  A total of 480 of the 538 recruited people underwent follow-up colonoscopy at the end of 5 years. In people with no baseline adenoma, 27.3 % (82/301) was found to have any adenoma, and 1.7 % had advanced adenoma at follow-up colonoscopy. The risk of an advanced adenoma did not differ significantly between people with no adenoma at baseline and those with nonadvanced adenoma (relative risk (RR), 1.06; 95 % confidence interval (CI), 0.19-6.07). Advanced adenoma at baseline colonoscopy was the independent risk factor for advanced adenoma recurrence, compared with no adenoma at baseline (RR, 8.25; 95 % CI, 1.90-35.77).
  
  
  CONCLUSIONS
  The risk of advanced adenoma is low 5 years after the normal baseline colonoscopy, even in asymptomatic Chinese Mongolian population over 50 years of age.
authors: Department of Gastroenterology, Affiliated Hospital of Inner Mongolia Medical College, Huhhot, Inner Mongolia Autonomous Region, 010050, People's Republic of China. hylmr@163.com
authors: Yinglong
authors: Y
authors: Huang
authors: Xiaohua
authors: X
authors: Li
authors: Zhaoyang
authors: Z
authors: Wang
authors: Bingzhong
authors: B
authors: Su
mesh_terms: D000236:Adenoma / Q000453:epidemiology; D044466:Asian People / Q000706:statistics & numerical data*; D002681:China / Q000453:epidemiology; D003113:Colonoscopy / Q000706:statistics & numerical data*; D015179:Colorectal Neoplasms / Q000453:epidemiology*; D005006:Ethnicity; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D012307:Risk Factors