Exposure to Polybrominated Diphenyl Ethers and Thyroid Disease: a Systematic Review and Meta-analysis of Epidemiological Studies

Environmental endocrine disruptors, such as polybrominated diphenyl ethers (PBDEs), have been suggested to be a possible risk factor for thyroid disease, but the association is still inconclusive. This study performed a meta-analysis of epidemiological studies to investigate the relationship between PBDE exposure and the risk of thyroid disease.

A total of nine epidemiological studies (published by January 20, 2023) reporting the association of PBDEs with thyroid disease were included. These studies investigated the effects of eight PBDE congeners and the sum of all PBDE congeners (∑PBDEs) and reported effect sizes and confidence intervals.

The results showed that high levels of BDE-183 exposure were associated with an increased risk of thyroid disease (OR = 3.26; 95% CI = 2.14–4.98). The relationship between other PBDE congeners and thyroid disease was not statistically significant. Subgroup analysis by region found that BDE-047 (OR = 2.62, 95% CI = 1.34–3.91), BDE-183 (OR = 2.92, 95% CI = 1.56–4.28), and ∑PBDEs (OR = 2.42, 95% CI = 1.31–3.53) were only associated with thyroid disease in Asian populations. No publication bias was detected by Egger’s test, and sensitivity analysis indicated the stability of the results. The present study suggests that exposure levels of certain PBDE congeners are associated with an increased risk of thyroid disease, only in Asian populations. Further large-scale and high-quality studies are needed to confirm these findings.