title: Intake of meat, meat mutagens, and iron and the risk of breast cancer in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial.
abstract: BACKGROUND
  Epidemiological evidence on meat intake and breast cancer is inconsistent, with little research on potentially carcinogenic meat-related exposures. We investigated meat subtypes, cooking practices, meat mutagens, iron, and subsequent breast cancer risk.
  
  
  METHODS
  Among 52 158 women (aged 55-74 years) in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial, who completed a food frequency questionnaire, 1205 invasive breast cancer cases were identified. We estimated meat mutagen and haem iron intake with databases accounting for cooking practices. Using Cox proportional hazards regression, we calculated hazard ratios (HRs) and 95% confidence intervals (CIs) within quintiles of intake.
  
  
  RESULTS
  Comparing the fifth to the first quintile, red meat (HR=1.23; 95% CI=1.00-1.51, P trend=0.22), the heterocyclic amine (HCA), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), (HR=1.26; 95% CI=1.03-1.55; P trend=0.12), and dietary iron (HR=1.25; 95% CI=1.02-1.52; P trend=0.03) were positively associated with breast cancer. We observed elevated, though not statistically significant, risks with processed meat, the HCA 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (DiMeIQx), mutagenic activity, iron from meat, and haem iron from meat.
  
  
  CONCLUSIONS
  In this prospective study, red meat, MeIQx, and dietary iron elevated the risk of invasive breast cancer, but there was no linear trend in the association except for dietary iron.
authors.affiliation: Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, Rockville, MD 20852, USA. ferruccil@mail.nih.gov
authors.forename: L M
authors.initials: LM
authors.lastname: Ferrucci
authors.forename: A J
authors.initials: AJ
authors.lastname: Cross
authors.forename: B I
authors.initials: BI
authors.lastname: Graubard
authors.forename: L A
authors.initials: LA
authors.lastname: Brinton
authors.forename: C A
authors.initials: CA
authors.lastname: McCarty
authors.forename: R G
authors.initials: RG
authors.lastname: Ziegler
authors.forename: X
authors.initials: X
authors.lastname: Ma
authors.forename: S T
authors.initials: ST
authors.lastname: Mayne
authors.forename: R
authors.initials: R
authors.lastname: Sinha
mesh_terms: D000368:Aged; D001943:Breast Neoplasms / Q000453:epidemiology; D015179:Colorectal Neoplasms / Q000453:epidemiology; D003296:Cooking; D005260:Female; D006801:Humans; D019266:Iron, Dietary / Q000008:administration & dosage*; D008175:Lung Neoplasms / Q000453:epidemiology; D008297:Male; D008403:Mass Screening / Q000379:methods; D008460:Meat; D008875:Middle Aged; D009153:Mutagens / Q000008:administration & dosage*; D009369:Neoplasms / Q000453:epidemiology*; D010051:Ovarian Neoplasms / Q000453:epidemiology; D016016:Proportional Hazards Models; D011471:Prostatic Neoplasms / Q000453:epidemiology; D011795:Surveys and Questionnaires
chemical_list: D019266:Iron, Dietary; D009153:Mutagens