Dietary N-nitroso compounds and risk of colorectal cancer: a case-control study in Newfoundland and Labrador and Ontario, Canada

Several N-nitroso compounds (NOC) have been shown to be carcinogenic in a variety of laboratory animals, but evidence of their carcinogenicity in humans is lacking. We aimed to examine the association between NOC intake and colorectal cancer (CRC) risk and possible effect modification by vitamins C...

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Bibliographic Details
Published in:British Journal of Nutrition
Main Authors: Zhu, Yun, Wang, Peizhong Peter, Zhao, Jing, Green, Roger, Sun, Zhuoyu, Roebothan, Barbara, Squires, Josh, Buehler, Sharon, Dicks, Elizabeth, Zhao, Jinhui, Cotterchio, Michelle, Campbell, Peter T., Jain, Meera, Parfrey, Patrick S., Mclaughlin, John R.
Format: Text
Language:English
Published: 2013
Subjects:
Article
Canada
Newfoundland
Online Access:http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4339287
http://www.ncbi.nlm.nih.gov/pubmed/24160559
https://doi.org/10.1017/S0007114513003462
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Summary:Several N-nitroso compounds (NOC) have been shown to be carcinogenic in a variety of laboratory animals, but evidence of their carcinogenicity in humans is lacking. We aimed to examine the association between NOC intake and colorectal cancer (CRC) risk and possible effect modification by vitamins C and E and protein in a large case-control study carried out in Newfoundland and Labrador, and Ontario, Canada. A total of 1760 case patients with pathologically confirmed adenocarcinoma and 2481 population controls were asked to complete a self-administered FFQ to evaluate their dietary intakes 1 year before diagnosis (for cases) or interview (for controls). Adjusted OR and 95% CI were calculated across the quintiles of NOC (measured by N-nitrosodimethylamine (NDMA)) intake and relevant food items using unconditional logistic regression. NDMA intake was found to be associated with a higher risk of CRC (highest vs lowest quintiles, OR: 1.42; 95% CI: 1.03,1.96; p-trend=0.005), specifically for rectal carcinoma (OR: 1.61; 95% CI: 1.11,2.35; p-trend=0.01). CRC risk also increased with the consumption of NDMA-containing meats when the highest tertile was compared with the lowest tertile (OR: 1.47; 95% CI: 1.03,2.10; p-trend=0.20). There was evidence of effect modification between dietary vitamin E and NDMA. Individuals with high NDMA and low vitamin E intakes had a significantly increased risk than those with both low NDMA and vitamin E intakes (OR:3.01; 95% CI: 1.43,6.51; p-interaction=0.017). The present results support the hypothesis that NOC intake may be positively associated with CRC risk in humans. Vitamin E, which inhibits nitrosation, could modify the effect of NDMA on CRC risk.

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