Maternal bisphenols exposure and thyroid function in children: a systematic review and meta-analysis.

Frontiers in endocrinology. 2024;15:1420540
Full text from:

Plain language summary

Bisphenols (BPs) are integral to plasticizers in the synthesis of polycarbonate plastics and epoxy resins. These chemicals can disrupt endocrine function, raising concerns about their impact on thyroid health, especially in vulnerable populations like pregnant women and their children. The primary aim of this study was to systematically review and analyse the effects of maternal bisphenol exposure on thyroid function in children, focusing on thyroid hormone levels and potential developmental impacts. This research is a systematic review and meta-analysis, incorporating data from multiple observational studies. Results showed that: - prenatal exposure to bisphenols reduced TSH and increased total triiodothyronine (TT3) [thyroid hormone] levels in female offspring. - maternal BPA exposure showed an inverse relationship with TT3 levels in male offspring. - high concentrations of bisphenol exposure have also been found to decrease free triiodothyronine (FT3) levels in offspring. Authors concluded that it is critical to strengthen control over prenatal exposure to bisphenols to safeguard early childhood health.

Abstract

BACKGROUND Evidence from animal experiments and epidemiological studies has reported controversial results about the effects of prenatal bisphenols (BPs) exposure on childhood thyroid function. This study aims to explore the associations of prenatal exposure to BPs with thyroid-related hormones (THs) in newborns and early childhood, with a particular focus on the sex-dependent and exposure level effects. METHODS Correlated studies were systematically searched from PubMed, Web of Science, Medline, Cochrane, and Embase until February 21, 2024. The exposures assessed include bisphenol A (BPA), bisphenol F (BPF), bisphenol S (BPS), bisphenol AF (BPAF), and tetrachlorobisphenol A (TCBPA). THs measured were thyroid stimulating hormone (TSH), total tri-iodothyronine (TT3), total thyroxine (TT4), free tri-iothyronine (FT3), and free thyroxine (FT4). Effect estimates were quantified using coefficients from multivariable regression models. Statistical analyses were completed using Stata 16.0. The methodological quality of the included studies was evaluated using the Newcastle-Ottawa Scale (NOS). RESULTS Eleven cohort studies comprising 5,363 children were included in our meta-analysis. Prenatal bisphenol concentrations were statistically significant related to alterations in thyroid hormones in children, exclusively in female offspring, including reduced TSH (β = -0.020, 95% CI: -0.036, -0.005) and increased TT3 levels (β = 0.011, 95% CI: 0.001, 0.021), and exposure to high concentration of bisphenols (>1.5 ug/g creatinine) significantly reduced FT3 levels in children (β = -0.011, 95% CI: -0.020, -0.003). CONCLUSION Prenatal bisphenol exposure is linked to alterations in thyroid hormone levels in girls, necessitating enhanced measures to control bisphenol exposure levels during pregnancy for child health protection. SYSTEMATIC REVIEW REGISTRATION https://inplasy.com, identifier INPLASY202450129.

Lifestyle medicine

Fundamental Clinical Imbalances : Hormonal ; Immune and inflammation
Patient Centred Factors : Mediators/Thyroid function
Environmental Inputs : Xenobiotics
Personal Lifestyle Factors : Environment
Functional Laboratory Testing : Not applicable

Methodological quality

Jadad score : Not applicable
Allocation concealment : Not applicable

Metadata