Combined Measure of Pro- and Anti-Oxidant Exposures in Relation to Prostate Cancer and Colorectal Adenoma Risk: An Update

PURPOSE: We previously proposed an oxidative balance score (OBS) and illustrated its practical application by using data from previously completed case-control studies of two neoplasms sporadic colorectal adenoma and prostate cancer. In the present study we extend our analysis by substituting questionnaire-based measures with systemic biomarkers of pro- and anti-oxidant exposures. METHODS: Low, medium and high pro-oxidant exposures, and high, medium and low antioxidant exposures were assigned 0, 1 and 2 points, respectively and individual points for all exposures were then summed to calculate the overall score. Case and controls were compared using logistic regression analysis after adjusting for covariates. RESULTS: When OBS was treated as a continuous variable the adjusted odds ratios and 95% confidence intervals (CI) for each additional score point were the same: 0.90 (95% Cl: 0.83-0.97) for each study. When the OBS was divided into three approximately equal intervals, a comparison of the lowest to highest category showed similar adjusted ORs (95% CIs) of 0.34 (0.13-0.88) and 0.34 (0.14-0.86) for colorectal adenoma and prostate cancer, respectively. CONCLUSIONS: Our analyses provide support for the stated hypothesis that combined measures of pro- and anti-oxidant exposures may be associated with oxidative stress-related conditions. Ann Epidemiol 2010;20:955-957. (C) 2010 Elsevier Inc. All rights reserved.