title: Television watching and risk of colorectal adenoma.
abstract: BACKGROUND
  Prolonged TV watching, a major sedentary behaviour, is associated with increased risk of obesity and diabetes and may involve in colorectal carcinogenesis.
  
  
  METHODS
  We conducted a cross-sectional analysis among 31 065 men with ⩾1 endoscopy in the Health Professionals Follow-up Study (1988-2008) to evaluate sitting while watching TV and its joint influence with leisure-time physical activity on risk of colorectal adenoma. Logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs).
  
  
  RESULTS
  Prolonged sitting while watching TV was significantly associated with increased risk of colorectal adenoma (n=4280), and adjusting for physical activity or a potential mediator body mass index did not change the estimates. The ORs (95% CIs) across categories of TV watching (0-6, 7-13, 14-20, and 21+ h per week) were 1.00 (referent), 1.09 (1.01-1.17), 1.16 (1.06-1.27), and 1.10 (0.97-1.25) (OR per 14-h per week increment=1.11; 95% CI: 1.04-1.18; Ptrend=0.001). Compared with the least sedentary (0-6 h per week of TV) and most physically active (highest quintile) men, the most sedentary (14+ h per week) and least active (lowest quintile) men had a significant increased risk of adenoma (OR=1.25; 95% CI: 1.05-1.49), particularly for high-risk adenoma.
  
  
  CONCLUSIONS
  Prolonged TV viewing is associated with modest increased risk of colorectal adenoma independent of leisure-time physical activity and minimally mediated by obesity.
authors.affiliation: Department of Nutrition, Harvard School of Public Health, 665 Huntington Avenue, Boston, MA 02115, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Cao
authors.affiliation: Department of Nutrition, Harvard School of Public Health, 665 Huntington Avenue, Boston, MA 02115, USA.
authors.forename: N N
authors.initials: NN
authors.lastname: Keum
authors.affiliation: 1] Division of Gastroenterology, Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114, USA [2] Channing Division of Network Medicine, Brigham and Women's Hospital and Harvard Medical School, 181 Longwood Avenue, Boston, MA 02115, USA.
authors.forename: A T
authors.initials: AT
authors.lastname: Chan
authors.affiliation: 1] Channing Division of Network Medicine, Brigham and Women's Hospital and Harvard Medical School, 181 Longwood Avenue, Boston, MA 02115, USA [2] Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, 450 Brookline Avenue, Boston, MA 02115, USA.
authors.forename: C S
authors.initials: CS
authors.lastname: Fuchs
authors.affiliation: Department of Nutrition, Harvard School of Public Health, 665 Huntington Avenue, Boston, MA 02115, USA.
authors.forename: K
authors.initials: K
authors.lastname: Wu
authors.affiliation: 1] Department of Nutrition, Harvard School of Public Health, 665 Huntington Avenue, Boston, MA 02115, USA [2] Channing Division of Network Medicine, Brigham and Women's Hospital and Harvard Medical School, 181 Longwood Avenue, Boston, MA 02115, USA [3] Department of Epidemiology, Harvard School of Public Health, 677 Huntington Avenue, Boston, MA 02115, USA.
authors.forename: E L
authors.initials: EL
authors.lastname: Giovannucci
mesh_terms: D000236:Adenoma / Q000453:epidemiology* / Q000209:etiology* / Q000473:pathology; D000328:Adult; D000368:Aged; D015992:Body Mass Index; D015179:Colorectal Neoplasms / Q000453:epidemiology* / Q000209:etiology* / Q000473:pathology; D003430:Cross-Sectional Studies; D006801:Humans; D007899:Leisure Activities; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications; D012307:Risk Factors; D057185:Sedentary Behavior; D013690:Television