Association between brominated flame retardants exposure and markers of oxidative stress in US adults: An analysis based on the National Health and Nutrition Examination Survey 2007–2016

We aimed to investigate the relationship between oxidative stress indicators and brominated flame retardant (BFR) levels in US adults. Using data from the NHANES (National Health and Nutrition Examination Survey) from 2007 to 2016, 8028 participants aged 18 and over were enrolled in this study. PBDE28, PBDE47, PBDE85, PBDE99, PBDE100, PBDE153, PBDE154, PBDE209, and PBB153, with over 75 % detection rates, were extracted in this study. Survey-weighted linear regression model, weighted quantile sum (WQS) model, and quantile-based g calculation (QGC) model were used to assess the correlation between serum BFRs levels and oxidative stress indicators (serum bilirubin and gamma-glutamyl transferase [GGT]). Besides, the nonlinear association was explored using restricted cubic splines (RCS). Each of the BFRs was confirmed by the survey-weighted linear regression model to be positively associated with GGT after controlling for variables, and BFRs except for PBDE153 were positively associated with serum bilirubin. Except for PBDE153, serum bilirubin in the highest quartile of BFRs was significantly higher than in the lowest high quartile. Additionally, except for PBDE85, serum GGT in the highest quartile of BFRs was higher than in the lowest high quartile. A significant nonlinear association between all BFRs with bilirubin and the PBDE153, PBDE209, and PBB153 with GGT was identified by RCS analysis. By WQS analysis, combined BFR exposure was associated with serum GGT (β: 0.093; 95 % CI = 0.066-0.121; P < 0.0001) and bilirubin (β: 0.090; 95 % CI = 0.068-0.113; P < 0.0001). QGC analysis found a similar correlation between BFR mixtures with serum GGT (β: 0.098; 95 % CI = 0.075-0.120; P < 0.0001) and bilirubin (β: 0.073; 95 % CI = 0.048-0.097; P < 0.0001). Exposure to BFRs is positively associated with markers of oxidative stress (serum bilirubin and GGT) in US adults, which needs further exploration by a large-scale cohort study.