Dietary and Lifestyle Oxidative Balance Scores and Incident Colorectal Cancer Risk among Older Women; the Iowa Women’s Health Study
Menée aux Etats-Unis à partir de données de questionnaires 1986-2012 portant sur 33 736 femmes (âge : 55-69 ans ; durée médiane de suivi : 24,2 personnes-années), cette étude analyse l'association entre des indicateurs caractérisant l'équilibre oxydant-antioxydant lié à l'alimentation ou au mode de vie et le risque de cancer colorectal (1 632 cas)
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) (Ptrend =0.02) and 0.61 (0.52, 0.71) (Ptrend <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.