Associations of oxidative balance-related exposures with incident, sporadic colorectal adenoma according to antioxidant enzyme genotypes

• Type of Material: Article
• Authors: Julia Labadie, Emory University; Michael Goodman, Emory University; Bharat Thyagarajan, University of Minnesota; Myron Gross, University of Minnesota; Yan Sun, Emory University; Veronika Fedirko, Emory University; Roberd M Bostick, Emory University
• Language: English
• Date: 2013-04
• Publisher: Elsevier: 12 months
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2012 Elsevier Inc. All rights reserved
• License: Creative Commons Attribution-NonCommerical-NoDerivs 3.0 Unported
• Final Published Version (URL): http://dx.doi.org/10.1016/j.annepidem.2012.12.001
• Title of Journal or Parent Work: Annals of Epidemiology
• ISSN: 1047-2797
• Volume: 23
• Issue: 4
• Start Page: 223
• End Page: 226
• Grant/Funding Information: Supported by National Cancer Institute, National Institutes of Health grants P01 CA50305, R01 CA66539, and R01 CA116795; Fullerton Foundation; Georgia Cancer Coalition Distinguished Scholar award (to R.M.B.); and the Franklin Foundation.
• Keywords: Antioxidant enzymes; Diet; Colorectal adenoma
• Research Categories: Health Sciences, Epidemiology; Health Sciences, Public Health; Health Sciences, General

Abstract

PURPOSE Previous research found inverse associations between oxidative balance and risk of colorectal adenoma. However, these measures were limited to extrinsic (dietary and lifestyle) exposures and did not account for intrinsic factors, specifically antioxidant enzymes responsible for cellular defense against oxidative stress. We investigated whether the association between an oxidative balance score (OBS) and colorectal adenoma may vary according to polymorphisms in genes that encode three antioxidant enzymes: manganese superoxide dismutase (SOD2), catalase (CAT), and glutathione-S-transferase P1 (GSTP1). METHODS Using data pooled from three colonoscopy-based case-control studies of incident, sporadic colorectal adenoma, we constructed an OBS reflecting pro- and anti-oxidant exposures. We used multivariable logistic regression to assess whether the association between the OBS and colorectal adenoma differed according to polymorphisms in the genes encoding the antioxidant enzymes. RESULTS The OBS was inversely associated with colorectal adenoma, adenoma risk was not associated with the genetic polymorphisms, and there was no consistent pattern of effect modification by individual genotypes or combined gene scores. CONCLUSIONS Variations in the antioxidant enzyme genes SOD2, CAT, and GSTP1 do not appear to substantially modify associations of environmental exposures related to oxidative balance with risk for sporadic colorectal adenoma.