Dietary and Lifestyle Oxidative Balance Scores and Incident Colorectal Cancer Risk among Older Women; the Iowa Women’s Health Study

Abstract

Background

Basic science literature strongly supports a role of oxidative stress in colorectal cancer (CRC) etiology, but in epidemiologic studies, associations of most individual exposures with CRC have been weak or inconsistent. However, recent epidemiologic evidence suggests that the collective effects of these exposures on oxidative balance and CRC risk may be substantial.

Methods

Using food frequency and lifestyle questionnaire data from the prospective Iowa Women’s Health Study (1986-2012), we investigated associations of 11-component dietary and 4-component lifestyle oxidative balance scores (OBS) with incident CRC using multivariable Cox proportional hazards regression.

Results

Of the 33,736 cancer-free women aged 55-69 years at baseline, 1,632 developed CRC during follow-up. Among participants in the highest relative to the lowest dietary and lifestyle OBS quintiles (higher anti-oxidant relative to pro-oxidant exposures), the adjusted hazard ratios (HRs) and their 95% confidence intervals (CI) were, respectively, 0.77 (0.63, 0.94) (P_trend=0.02) and 0.61 (0.52, 0.71) (P_trend<0.0001). Among those in the highest relative to the lowest joint lifestyle/dietary OBS quintile, the HR was 0.45 (95% CI 0.26, 0.77).

Conclusions

Our findings suggest that a predominance of antioxidant over pro-oxidant dietary and lifestyle exposures—separately and especially jointly—may be inversely associated with CRC risk among older women.

Disclosure Statement

None of the authors has a conflict of interest to disclose. The findings and conclusions contained within are those of the authors and do not necessarily reflect positions or policies of the National Cancer Institute or the Wilson P. and Anne W. Franklin Foundation. The National Cancer Institute and the Wilson P. and Anne W. Franklin Foundation had no influence on the analysis and interpretation of the data, the decision to submit the manuscript for publication, or the writing of the manuscript.

Authors’ Contributions

Conception and design: Z. Mao, R.M. Bostick

Development of methodology: Z. Mao, R.M. Bostick

Acquisition of data: A. E. Prizment, D. Lazovich

Analysis and interpretation of data: Z. Mao, D. C. Gibbs, A. E. Prizment, D. Lazovich, R.M. Bostick

Writing, review, and/or revision of the manuscript: Z. Mao, D. C. Gibbs, A. E. Prizment, D. Lazovich, R.M. Bostick

Administrative, technical, or material support: A. E. Prizment, D. Lazovich

Study supervision: R.M. Bostick

Additional information

Funding

This work was supported by the National Cancer Institute at the National Institutes of Health under Grant R01 CA039742, and the Wilson P. and Anne W. Franklin Foundation.