title: Meat consumption and the risk of incident distal colon and rectal adenoma.
abstract: BACKGROUND
  Most studies of meat and colorectal adenoma have investigated prevalent events from a single screening, thus limiting our understanding of the role of meat and meat-related exposures in early colorectal carcinogenesis.
  
  
  METHODS
  Among participants in the screening arm of the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial who underwent baseline and follow-up sigmoidoscopy (n=17,072), we identified 1008 individuals with incident distal colorectal adenoma. We calculated odds ratios (ORs) and 95% confidence intervals (95% CIs) for associations between meat and meat-related components and incident distal colorectal adenoma using multivariate logistic regression.
  
  
  RESULTS
  We observed suggestive positive associations for red meat, processed meat, haeme iron, and nitrate/nitrite with distal colorectal adenoma. Grilled meat (OR=1.56, 95% CI=1.04-2.36), well or very well-done meat (OR=1.59, 95% CI=1.05-2.43), 2-amino-1-methyl-6-phenyl-imidazo[4,5-b]pyridine (PhIP) (OR=1.75, 95% CI=1.17-2.64), benzo[a]pyrene (OR=1.53, 95% CI=1.06-2.20), and total mutagenic activity (OR=1.57, 95% CI=1.03-2.40) were positively associated with rectal adenoma. Total iron (diet and supplements) (OR=0.69, 95% CI=0.56-0.86) and iron from supplements (OR=0.65, 95% CI=0.44-0.97) were inversely associated with any distal colorectal adenoma.
  
  
  CONCLUSIONS
  Our findings indicate that several meat-related components may be most relevant to early neoplasia in the rectum. In contrast, total iron and iron from supplements were inversely associated with any distal colorectal adenoma.
authors.affiliation: Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, MD, USA.
authors.forename: L M
authors.initials: LM
authors.lastname: Ferrucci
authors.forename: R
authors.initials: R
authors.lastname: Sinha
authors.forename: W-Y
authors.initials: WY
authors.lastname: Huang
authors.forename: S I
authors.initials: SI
authors.lastname: Berndt
authors.forename: H A
authors.initials: HA
authors.lastname: Katki
authors.forename: R E
authors.initials: RE
authors.lastname: Schoen
authors.forename: R B
authors.initials: RB
authors.lastname: Hayes
authors.forename: A J
authors.initials: AJ
authors.lastname: Cross
mesh_terms: D000236:Adenoma / Q000453:epidemiology* / Q000209:etiology; D000368:Aged; D003106:Colon / Q000473:pathology; D015179:Colorectal Neoplasms / Q000453:epidemiology* / Q000209:etiology / Q000517:prevention & control; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008460:Meat; D008875:Middle Aged; D012307:Risk Factors; D012812:Sigmoidoscopy; D014481:United States / Q000453:epidemiology