title: Colorectal Neoplasm in Asymptomatic Average-risk Koreans: The KASID Prospective Multicenter Colonoscopy Survey.
abstract: OBJECTIVE
  The incidence of colorectal cancer is increasing in Korea, but the epidemiology of colorectal neoplasm is not clearly defined. We aimed to elucidate the prevalence of colorectal neoplasm in average-risk Koreans and explore the underlying risk factors.
  
  
  METHODS
  A large-scale, multicenter, prospective study was conducted. Of the 19,460 subjects who underwent colonoscopy at 11 university hospitals, we analyzed 3,951 consecutive asymptomatic adults with no risk factors for colorectal cancer.
  
  
  RESULTS
  The subjects were aged 52.1+/-11.6 years (mean+/-SD) and 60.1% of them were men. The prevalences of colorectal neoplasm and advanced neoplasm were 33.3% and 2.2%, respectively. The prevalence of a neoplasm increased with age (trend: p<0.001) and was higher in males (p<0.001). The prevalence of a proximal neoplasm was higher in subjects with a distal neoplasm than in those without a distal neoplasm (11.9% vs. 5.4%, p<0.001). However, 150 (52.1%) of the 288 subjects with a proximal neoplasm had no distal neoplasm.
  
  
  CONCLUSIONS
  The overall prevalence of colorectal neoplasm in asymptomatic average-risk Koreans is comparable with that in Western countries. Being male and older are associated with a higher risk of colorectal neoplasm. Over half of proximal neoplasms are not associated with any distal sentinel lesions.
authors.affiliation: Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Hye-Won
authors.initials: HW
authors.lastname: Park
authors.forename: Jeong-Sik
authors.initials: JS
authors.lastname: Byeon
authors.forename: Suk-Kyun
authors.initials: SK
authors.lastname: Yang
authors.forename: Hyun Soo
authors.initials: HS
authors.lastname: Kim
authors.forename: Won Ho
authors.initials: WH
authors.lastname: Kim
authors.forename: Tae Il
authors.initials: TI
authors.lastname: Kim
authors.forename: Dong Il
authors.initials: DI
authors.lastname: Park
authors.forename: Young-Ho
authors.initials: YH
authors.lastname: Kim
authors.forename: Hyo Jong
authors.initials: HJ
authors.lastname: Kim
authors.forename: Moon Sung
authors.initials: MS
authors.lastname: Lee
authors.forename: Il-Kwon
authors.initials: IK
authors.lastname: Chung
authors.forename: Sung-Ae
authors.initials: SA
authors.lastname: Jung
authors.forename: Yoon Tae
authors.initials: YT
authors.lastname: Jeen
authors.forename: Jai Hyun
authors.initials: JH
authors.lastname: Choi
authors.forename: Hwang
authors.initials: H
authors.lastname: Choi
authors.forename: Kyu Yong
authors.initials: KY
authors.lastname: Choi
authors.forename: Dong Soo
authors.initials: DS
authors.lastname: Han
authors.forename: Jae Suk
authors.initials: JS
authors.lastname: Song