title: Underestimation of Smoking Rates in an East Asian Population with Crohn's Disease.
abstract: OBJECTIVE
  The reported rates of current smoking at the time of Crohn's disease (CD) diagnosis tend to be low in East Asian studies. However, we hypothesized that East Asian patients may be reluctant to disclose their smoking history, likely because of the influence of the Confucian culture.
  
  
  METHODS
  We prospectively re-evaluated the smoking status at diagnosis in 1,437 Korean CD patients whose smoking status had been reported in our previous study.
  
  
  RESULTS
  After re-evaluation, the current smokers at diagnosis increased from 388 patients (27.0%) to 445 patients (31.0%), indicating that 12.8% (57 of 445 patients) of the current smokers at diagnosis did not disclose their smoking status at their initial evaluation. The proportion of current smokers at diagnosis who had initially concealed their smoking status was significantly higher among the female patients (29.7%, 11/37) compared with the male patients (11.3%, 46/408) (p<0.005) and among the patients who were ≤18 years old at diagnosis (56.4%, 22/39) compared with the patients >18 years old at diagnosis (8.6%, 35/406) (p<0.001).
  
  
  CONCLUSIONS
  Subgroups of Korean CD patients, particularly young patients and female patients, are reluctant to disclose their smoking history. Therefore, the suggestion that smoking is not a risk factor for the development of CD in East Asians should be made with caution.
authors.affiliation: Department of Gastroenterology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Sung Wook
authors.initials: SW
authors.lastname: Hwang
authors.affiliation: Department of Gastroenterology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Hyungil
authors.initials: H
authors.lastname: Seo
authors.affiliation: Department of Gastroenterology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Gwang-Un
authors.initials: GU
authors.lastname: Kim
authors.affiliation: Department of Gastroenterology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Eun Mi
authors.initials: EM
authors.lastname: Song
authors.affiliation: Department of Gastroenterology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Myeongsook
authors.initials: M
authors.lastname: Seo
authors.affiliation: Department of Gastroenterology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Sang Hyoung
authors.initials: SH
authors.lastname: Park
authors.affiliation: Department of Gastroenterology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Eunja
authors.initials: E
authors.lastname: Kwon
authors.affiliation: Health Screening and Promotion Center, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Ho-Su
authors.initials: HS
authors.lastname: Lee
authors.affiliation: Department of Gastroenterology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Dong-Hoon
authors.initials: DH
authors.lastname: Yang
authors.affiliation: Department of Gastroenterology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Kyung-Jo
authors.initials: KJ
authors.lastname: Kim
authors.affiliation: Department of Gastroenterology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Byong Duk
authors.initials: BD
authors.lastname: Ye
authors.affiliation: Department of Gastroenterology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Jeong-Sik
authors.initials: JS
authors.lastname: Byeon
authors.affiliation: Department of Gastroenterology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Seung-Jae
authors.initials: SJ
authors.lastname: Myung
authors.affiliation: Department of Gastroenterology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Jin-Ho
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Department of Gastroenterology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Suk-Kyun
authors.initials: SK
authors.lastname: Yang
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D003424:Crohn Disease / Q000453:epidemiology*; D030881:Disclosure; D005202:Asia, Eastern / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011446:Prospective Studies; D056910:Republic of Korea / Q000453:epidemiology; D012307:Risk Factors; D057566:Self Report; D012737:Sex Factors; D012907:Smoking / Q000453:epidemiology*; D055815:Young Adult
keywords: Age at diagnosis; Crohn disease; Sex; Smoking