Associations of dietary and lifestyle oxidative balance scores with mortality risk among older women: the Iowa Women’s Health Study

Purpose: Substantial basic science evidence suggests that oxidative stress may play a role in aging-related health outcomes, including cardiovascular diseases (CVD) and cancer, and oxidative stress markers were linked with all-cause and cause-specific mortality in epidemiologic studies. However, the associations of many individual dietary and lifestyle anti-/pro-oxidant exposures with mortality are inconsistent. Oxidative balance scores (OBS) that incorporated multiple dietary and lifestyle factors were previously developed and reported to reflect the collective oxidative effects of multiple exposures. Methods: We investigated associations of 11-component dietary and 4-component (physical activity, adiposity, alcohol, and smoking) lifestyle OBS (higher scores were considered more anti-oxidative) with all-cause and cause-specific mortality among women 55–69 years of age at baseline in the prospective Iowa Women’s Health Study (1986–2012). We assessed OBS-mortality associations using multivariable Cox proportional hazards regression. Results: Of the 34,137 cancer-free women included in the analytic cohort, 18,058 died (4521 from cancer, and 6825 from CVD) during a mean/median 22.0/26.1 person-years of follow-up. Among participants in the highest relative to the lowest lifestyle OBS quintiles, the adjusted hazards ratios and their 95% confidence intervals for all-cause, all-cancer, and all-CVD mortality were 0.50 (0.48, 0.53), 0.47 (0.43, 0.52), and 0.54 (0.50, 0.58) (all P_trend < 0.001), respectively. The associations of the dietary OBS with mortality were close to null. Conclusion: Our findings, combined with results from previous studies, suggest that a predominance of antioxidant over pro-oxidant lifestyle exposures may be associated with lower all-cause, all-CVD, and all-cancer mortality risk.