The association of urinary phosphorous-containing flame retardant metabolites and oxidative stress among pregnant women in Puerto Rico

Abstract

PDS 71: Exposome, Johan Friso Foyer, Floor 1, August 27, 2019, 4:30 PM - 5:30 PM Background: Phosphorous-containing flame retardants (PFRs) are frequently used as flame retardants and plasticizers. Previous research has suggested oxidative stress, the imbalance of reactive oxygen species and antioxidants, is a possible mechanism for pollutant-induced health effects. Oxidative stress measured prenatally has been associated with adverse birth outcomes including preeclampsia and preterm birth. To our knowledge, only one human study has explored associations between PFRs and oxidative stress. Methods: Pregnant women 18-40 yrs. were recruited from two hospitals and five prenatal clinics in Northern Puerto Rico (n=47) between 2011 and 2015. Concentrations of: bis(2-chloroethyl) phosphate (BCEtP), bis(1-chloro-2-propyl) phosphate (BCPP), bis(1,3-dichloro-2-propyl) phosphate (BDCPP), and diphenyl phosphate (DPHP) were measured in urine up to two times during pregnancy. Biomarkers for oxidative stress, 8-hydroxydeoxyguanosine (8-OHdG) and 8-isoprostane, were also measured in urine up to two times during pregnancy. Associations between oxidative stress biomarkers and PFRs were assessed using linear mixed models adjusted for specific gravity, age, BMI, income, and season. Results: PFR metabolites were frequently detected (≥77%). All metabolites were associated with a statistically significant increase in 8-OHdG and 8-isoprostane levels (p<0.05). BDCPP was associated with the highest increase of 8-OHdG (β=0.29; p<0.0001) while BCEtP and BCPP had the lowest increase (β=0.15; p<0.01). Similarly, BCEtP was associated with the lowest increase of 8-isoprostane levels (β=0.13; p=0.04), while BCPP was associated with the largest increase (β=0.30; p<0.0001). Conclusion: PFR metabolites were frequently detected and although our sample size was modest, our results suggest that exposure to PFRs is associated with higher levels of oxidative stress. Further investigation into these relationships and birth outcomes is warranted.