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 (n17 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 (OR1.56, 95% CI1.04-2.36), well or very well-done meat (OR1.59, 95% CI1.05-2.43), 2-amino-1-methyl-6-phenyl-imidazo4,5-bpyridine (PhIP) (OR1.75, 95% CI1.17-2.64), benzoapyrene (OR1.53, 95% CI1.06-2.20), and total mutagenic activity (OR1.57, 95% CI1.03-2.40) were positively associated with rectal adenoma. Total iron (diet and supplements) (OR0.69, 95% CI0.56-0.86) and iron from supplements (OR0.65, 95% CI0.44-0.97) were inversely associated with any distal colorectal adenoma. Conclusion: 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. © 2012 Cancer Research UK.