Dietary Fat Subgroups, Zinc, and Vegetable Components Are Related to Urine F₂a-Isoprostane Concentration, a Measure of Oxidative Stress, in Midlife Women

Smoking, diet, and physical activity may impact chronic diseases in part by promoting or attenuating oxidative stress. We evaluated associations between lifestyle factors and urine F₂a-isoprostanes, a marker of oxidative stress in 1610 participants of the Study of Women's Health Across the Nation (SWAN). Dietary intake and physical activity were assessed at baseline and the 5th year 05 (Y05). These data were related to Y05 urinary F₂a-isoprostane concentration with regression analyses. Median urine F₂a-isoprostane concentration was 433 ng/L overall, 917 ng/L in smokers [inter-quartile range (IQR): 467, 1832 ng/L], and 403 ng/L in nonsmokers (IQR: 228, 709 ng/L; P < 0.0001 for difference). Higher trans fat intake was associated with higher urine F₂a-isoprostane concentration; partial Spearman correlations (ρx|y) between Y05 urine F₂a-isoprostane concentration and trans fatty acids was 0.19 (P = 0.03) in smokers and 0.13 (P < 0.0001) in nonsmokers. Increased log trans fat intake from baseline to Y05 was associated with higher concentration of log urine F₂a-isoprostanes in nonsmokers (β = 0.131, SE = 0.04, P = 0.0003). In nonsmokers, the partial correlation (ρx|y) between lutein and urine F₂a-isoprostane concentration was -0.13 (P < 0.0001). Increased intake of log lutein from baseline to Y05 was also associated with lower log urine F₂a-isoprostane concentration (β = -0.096, SE = 0.03, P = 0.0005) in nonsmokers. Increased zinc intake from baseline to Y05 was associated with lower log urine F₂a-isoprostane concentration in smokers and nonsmokers (β = -0.346, SE = 0.14, P = 0.01), and -0.117, 0.04 (P = 0.001), respectively]. In conclusion, diet (fat subtypes, zinc, and vegetable components) and smoking were associated with urine F₂a-isoprostanes, a marker of oxidative stress.