Association of brominated flame retardant exposure with thyroid disease risk: A cross-sectional study of US adults

Brominated flame retardants (BFRs) are pervasive environmental contaminants with potential health risks. This study aimed to assess the impact of combined BFR exposure on thyroid function and identify key chemicals contributing to these effects. We analyzed data from 6763 participants in the National Health and Nutrition Examination Survey (NHANES) from 2005 to 2016. Logistic regression with weighted data and Restricted Cubic Splines (RCS) were used to examine the relationship between BFR exposure and thyroid disease (TD). To evaluate the impact of BFR mixtures on thyroid function, we employed weighted quantile sum (WQS) regression and Bayesian kernel machine regression (BKMR) models. We also explored subgroup variability. Logistic regression showed a significant positive correlation between TD and BFRs PBB153, PBDE28, and PBDE154 (P < .05), with a nonlinear relationship for PBB153 (P = .021). WQS analysis indicated a positive association between BFR mixtures and TD (OR > 1, P = .0146), supported by BKMR results. PBB153 was identified as the most influential chemical in both models. Subgroup analysis revealed a stronger link between BFR exposure and TD in females than males. The study demonstrated a positive correlation between adult TD and combined BFR exposure, with PBB153, PBDE153, and PBDE154 being particularly influential. Interestingly, serum BFR levels negatively predicted TD in males, suggesting gender-specific effects. This research highlights the importance of considering BFR mixtures in thyroid health assessments.