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 (HR1.23; 95% CI1.00-1.51, P trend0.22), the heterocyclic amine (HCA), 2-amino-3,8-dimethylimidazo4,5-fquinoxaline (MeIQx), (HR1.26; 95% CI1.03-1.55; P trend0.12), and dietary iron (HR1.25; 95% CI1.02-1.52; P trend0.03) were positively associated with breast cancer. We observed elevated, though not statistically significant, risks with processed meat, the HCA 2-amino-3,4,8-trimethylimidazo4,5-fquinoxaline (DiMeIQx), mutagenic activity, iron from meat, and haem iron from meat.Conclusion: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.
Bibliographical noteFunding Information:
This research was supported (in part) by the Intramural Research Program of the National Institutes of Health, National Cancer Institute, by grant TU2 CA105666 from the National Cancer Institute, and by contracts from the Division of Cancer Prevention, National Cancer Institute, National Institutes of Health. The authors thank Drs Christine Berg and Philip Prorok, the Screening Centre investigators and staff of the PLCO Cancer Screening Trial and, Information Management Services, Inc.
- Breast cancer