title: Tobacco smoking: a factor of early onset of colorectal cancer.
abstract: OBJECTIVE
  Tobacco smoking is associated with a higher risk of developing colorectal cancer. This study was designed to assess the role of smoking in early onset of colorectal pathology.
  
  
  METHODS
  This was a prospective cross-sectional study of 997 patients with colorectal cancer. Age of colorectal cancer diagnosis was studied in two groups of patients, i.e., smokers (>10 pack-years) and nonsmokers. Confounding factors, such as alcohol drinking, obesity, and gender, also were studied using a correlation analysis and multivariate logistic regression analysis.
  
  
  RESULTS
  Of the 997 patients, 852 had sufficient data for analysis and were included. Baseline analysis showed that excluded patients had similar demographic characteristics. Smokers (n=108) reported symptoms related to colorectal cancer at an earlier mean age (64.1 (standard deviation, 11.7) years) than nonsmokers (69.6 (standard deviation, 12.6) years; mean difference, 5.5 (standard deviation, 1.2 years); P<0.001). Impact of smoking according to the bowel segment involved was significant for slow-transit segments (transverse and sigmoid colon and rectum). Multivariate analysis revealed that tobacco smoking was the only independent risk factor of early onset of colorectal cancers.
  
  
  CONCLUSIONS
  Tobacco smoking could be a factor of early onset of colorectal cancers especially for slow-transit bowel segments. If these findings are confirmed in larger studies, screening for colorectal cancer should not involve a simple sigmoidoscopy but also an exploration of transverse colon in smokers.
authors.affiliation: Department of General and Digestive Surgery, Hôtel-Dieu, Boulevard Leon Malfreyt, F-63058, Clermont-Ferrand, France.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Buc
authors.forename: Fabrice
authors.initials: F
authors.lastname: Kwiatkowski
authors.forename: Arnaud
authors.initials: A
authors.lastname: Alves
authors.forename: Yves
authors.initials: Y
authors.lastname: Panis
authors.forename: Georges
authors.initials: G
authors.lastname: Mantion
authors.forename: Karem
authors.initials: K
authors.lastname: Slim
mesh_terms: D017668:Age of Onset; D000368:Aged; D012809:Colon, Sigmoid / Q000473:pathology; D044684:Colon, Transverse / Q000473:pathology; D015179:Colorectal Neoplasms / Q000175:diagnosis / Q000453:epidemiology*; D003430:Cross-Sectional Studies; D005260:Female; D005602:France / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011446:Prospective Studies; D012007:Rectum / Q000473:pathology; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects*