Association between PFAS exposure and thyroid health: A systematic review and meta-analysis for adolescents, pregnant women, adults and toxicological evidence

A burgeoning body of epidemiological and toxicological evidence suggests that thyroid health may be significantly impacted by exposure to both long- and short-chain perfluoroalkyl substances (PFAS) compounds. We conducted a meta-analysis to examine the association between 16 PFAS compounds and five thyroid hormones (TSH, TT3, TT4, FT3, and FT4) in the serum of a pregnant women, adolescents, and adults. The dose-response relationship between some PFAS and thyroid hormones in different population subpopulation was found and the model was fitted. We also amalgamated data from 18 animal experiments with previously published in vitro studies to elucidate the toxicological mechanisms underlying the impact of PFAS on the thyroid gland. The results of the study showed that (a) both conventional and emerging PFAS compounds were identified in human samples and exhibited associations with thyroid health outcomes; (b) in animal studies, PFAS have been found to impact thyroid gland health through two primary mechanisms: by influencing the hypothalamic-pituitary-thyroid axis and by binding to thyroid receptors. This study provides a systematic description of the health effects and risk assessment associated with PFAS exposure on the thyroid gland. Furthermore, dose-response relationships were established through the Hill model in python.