Antioxidant and pro-oxidant dietary consumption patterns and their association with prostate cancer: a case-control study from Mexico City.

To assess the association between dietary consumption patterns of antioxidant and pro-oxidant nutrients with prostate cancer (PC) and its histological differentiation, we analysed data from 394 histologically confirmed incident cases of PC and 793 age-matched population controls (±5 years), residents of Mexico City. Cases were classified by Gleason score into well-differentiated, moderately differentiated and poorly differentiated categories. Dietary nutrient intake over the 3 years preceding diagnosis for cases and before the interview for controls was estimated using a semi-quantitative FFQ. Using energy-adjusted residuals and a k-means approach, we identified three consumption patterns: (1) pro-oxidant, (2) moderate antioxidants/low pro-oxidants and (3) high antioxidants and pro-oxidants. Associations were evaluated using independent unconditional logistic regression models; stratified models were analysed based on smoking status. Although proportions differed, the main food contributors to the moderate antioxidants/low pro-oxidants and high antioxidants and pro-oxidants patterns included green vegetables, maize tortillas, seeds and fruits. Compared with the pro-oxidant pattern, the moderate antioxidants/low pro-oxidants (OR: 0·71; 95 % CI 0·53, 0·97) and high antioxidants and pro-oxidants (OR: 0·70; 95 % CI 0·50, 0·99) patterns were associated with lower odds of having PC. These associations were mainly observed with well-differentiated PC and among ever-smokers. Diets with a higher antioxidant content were associated with a reduced likelihood of PC. Further validation of these findings through prospective studies is needed.