title: A large prospective study of meat consumption and colorectal cancer risk: an investigation of potential mechanisms underlying this association.
abstract: Although the relation between red and processed meat intake and colorectal cancer has been reported in several epidemiologic studies, very few investigated the potential mechanisms. This study examined multiple potential mechanisms in a large U.S. prospective cohort with a detailed questionnaire on meat type and meat cooking methods linked to databases for estimating intake of mutagens formed in meats cooked at high temperatures (heterocyclic amines, polycyclic aromatic hydrocarbons), heme iron, nitrate, and nitrite. During 7 years of follow-up, 2,719 colorectal cancer cases were ascertained from a cohort of 300,948 men and women. The hazard ratios (HR) and 95% confidence intervals (95% CI) comparing the fifth to the first quintile for both red (HR, 1.24; 95% CI, 1.09-1.42; P(trend) < 0.001) and processed meat (HR, 1.16; 95% CI, 1.01-1.32; P(trend) = 0.017) intakes indicated an elevated risk for colorectal cancer. The potential mechanisms for this relation include heme iron (HR, 1.13; 95% CI, 0.99-1.29; P(trend) = 0.022), nitrate from processed meats (HR, 1.16; 95% CI, 1.02-1.32; P(trend) = 0.001), and heterocyclic amine intake [HR, 1.19; 95% CI, 1.05-1.34; P(trend) < 0.001 for 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) and HR, 1.17; 95% CI, 1.05-1.29; P(trend) <0.001 for 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (DiMeIQx)]. In general, the elevated risks were higher for rectal cancer than for colon cancer, with the exception of MeIQx and DiMeIQx, which were only associated with colon cancer. In conclusion, we found a positive association for red and processed meat intake and colorectal cancer; heme iron, nitrate/nitrite, and heterocyclic amines from meat may explain these associations.
authors.affiliation: Nutritional Epidemiology Branch, Biostatistics Branch, Division of Cancer Epidemiology and Genetics, Department of Health and Human Services, National Cancer Institute, NIH, Rockville, Maryland, USA. crossa@mail.nih.gov
authors.forename: Amanda J
authors.initials: AJ
authors.lastname: Cross
authors.forename: Leah M
authors.initials: LM
authors.lastname: Ferrucci
authors.forename: Adam
authors.initials: A
authors.lastname: Risch
authors.forename: Barry I
authors.initials: BI
authors.lastname: Graubard
authors.forename: Mary H
authors.initials: MH
authors.lastname: Ward
authors.forename: Yikyung
authors.initials: Y
authors.lastname: Park
authors.forename: Albert R
authors.initials: AR
authors.lastname: Hollenbeck
authors.forename: Arthur
authors.initials: A
authors.lastname: Schatzkin
authors.forename: Rashmi
authors.initials: R
authors.lastname: Sinha
mesh_terms: D015331:Cohort Studies; D015179:Colorectal Neoplasms / Q000453:epidemiology* / Q000209:etiology; D003296:Cooking; D004032:Diet / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D007093:Imidazoles / Q000032:analysis; D008297:Male; D008460:Meat / Q000032:analysis / Q000706:statistics & numerical data*; D008875:Middle Aged; D011446:Prospective Studies; D011810:Quinoxalines / Q000032:analysis; D011795:Surveys and Questionnaires; D014481:United States / Q000453:epidemiology
chemical_list: D007093:Imidazoles; D011810:Quinoxalines; C036990:2-amino-3,8-dimethylimidazo(4,5-f)quinoxaline; C049584:2-amino-1-methyl-6-phenylimidazo(4,5-b)pyridine; C042052:2-amino-3,7,8-trimethylimidazo(4,5-f)quinoxaline