Abstract 4645: Lifestyle and dietary oxidative balance scores and risk for incident colorectal cancer among older women: The Iowa Women's Health Study

Abstract

Abstract Background: Basic science literature strongly supports a role of oxidative stress in colorectal cancer (CRC) etiology; however, in epidemiologic studies, associations of individual lifestyle and dietary anti- and pro-oxidant exposures with CRC have been largely inconsistent. However, recent epidemiologic evidence suggests that the collective effects of these exposures on oxidative balance and CRC risk may be substantial. Methods: From lifestyle and food frequency questionnaire data from the prospective Iowa Women's Health Study (1986 - 2012), we calculated equal-weight, 4-component lifestyle and 11-component dietary oxidative balance scores (OBS), and investigated their separate and joint associations with incident CRC using multivariable Cox proportional hazards regression. Results: Of the 34,135 cancer-free women aged 55 to 69 at baseline, 1,635 developed CRC during follow-up. Among participants in the highest lifestyle and dietary OBS quintiles (higher anti-oxidant relative to pro-oxidant exposures) relative to the lowest, the multivariable-adjusted hazard ratios (HRs) were, respectively, 0.63 (95% confidence interval (CI), 0.54-0.73; Ptrend < 0.0001) and 0.77 (95% CI, 0.64-0.94; Ptrend = 0.01. The lowest risk was among those in the highest relative to the lowest joint lifestyle/dietary OBS quintile (HR = 0.47; 95% CI, 0.29-0.76). Conclusions: Our findings suggest that a predominance of antioxidant over pro-oxidant lifestyle and dietary exposures–especially lifestyle separately and jointly with dietary exposures–may be inversely associated with CRC risk among older women. Citation Format: Ziling Mao, Anna E. Prizment, DeAnn Lazovich, David C. Gibbs, Roberd M. Bostick. Lifestyle and dietary oxidative balance scores and risk for incident colorectal cancer among older women: The Iowa Women's Health Study [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4645.