A longitudinal study of atrazine and 2,4-D exposure and oxidative stress markers among iowa corn farmers

Reactive oxygen species, potentially formed through environmental exposures, can overwhelm an organism's antioxidant capabilities resulting in oxidative stress. Long‐term oxidative stress is linked with chronic diseases. Pesticide exposures have been shown to cause oxidative stress in vivo. We utilized a longitudinal study of corn farmers and non‐farming controls in Iowa to examine the impact of exposure to the widely used herbicides atrazine and 2,4‐dichlorophenoxyacetic acid (2,4‐D) on markers of oxidative stress. 225 urine samples were collected during five agricultural time periods (pre‐planting, planting, growing, harvest, off‐season) for 30 farmers who applied pesticides occupationally and 10 controls who did not; all were non‐smoking men ages 40–60. Atrazine mercapturate (atrazine metabolite), 2,4‐D, and oxidative stress markers (malondialdehyde [MDA], 8‐hydroxy‐2′‐deoxyguanosine [8‐OHdG], and 8‐isoprostaglandin‐F2α [8‐isoPGF]) were measured in urine. We calculated β estimates and 95% confidence intervals (95%CI) for each pesticide‐oxidative stress marker combination using multivariate linear mixed‐effect models for repeated measures. Farmers had higher urinary atrazine mercapturate and 2,4‐D levels compared with controls. In regression models, after natural log transformation, 2,4‐D was associated with elevated levels of 8‐OHdG (β = 0.066, 95%CI = 0.008–0.124) and 8‐isoPGF (β = 0.088, 95%CI = 0.004–0.172). 2,4‐D may be associated with oxidative stress because of modest increases in 8‐OHdG, a marker of oxidative DNA damage,...