Background

The epidemiological evidence on the associations between prenatal exposure to perfluoroalkyl substances (PFAS) and thyroid hormones in newborns was inconclusive.

Objectives

We aimed to estimate associations of fetal exposure to PFAS individually and in mixtures with thyroid function of newborns.

Methods

A total of 490 mother-newborn pairs were included from Sheyang Mini Birth Cohort Study (SMBCS), a prospective cohort that recruited between June 2009 and January 2010. 12 PFAS and 7 thyroid function indicators were quantified in umbilical cord serum. We examined associations of prenatal exposure to individual and a mixture of PFAS with thyroid function indicators using multivariable linear regression and weighted quantile sum (WQS) regression models with adjustment for potential confounders, respectively.

Results

Higher cord serum concentrations of PFAS mixtures were related to increases in TT4 and FT4 levels, and reductions in TSH concentrations of newborns. Combining single-chemical models with multiple-chemical models, PFOS, PFNA and PFUnDA were associated with increased TT4 levels with contributing to the mixture effects of 46.4%, 22.8%, and 16.7%, respectively. PFOS exposure was in positive association with cord serum FT4 concentrations and contributed 28.9% to the joint effects of mixtures. PFNA and PFHpA were the most important contributors to the decreases of TSH levels of newborns with 46.3% and 45.0% among the mixtures, respectively.

Conclusions

The current findings indicated the thyroid disruption of individual PFAS and their mixtures in cord serum. Additional studies are warranted to explore the underlying biological mechanisms, particularly for PFAS mixtures.

中文翻译：

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脐带血全氟烷基物质混合物与新生儿甲状腺功能的关系：射阳微型出生队列研究的结果

背景

关于新生儿产前暴露于全氟烷基物质（PFAS）与甲状腺激素之间的关联的流行病学证据尚无定论。

目标

我们的目的是估计胎儿单独和与新生儿甲状腺功能混合时暴露于PFAS的关联。

方法

2009年6月至2010年1月间进行的一项前瞻性队列射阳微型出生队列研究（SMBCS）总共纳入了490对母婴。在脐带血清中定量了12种PFAS和7种甲状腺功能指标。我们分别通过多变量线性回归和加权分位数和（WQS）回归模型对潜在混杂因素进行了调整，检验了产前暴露于个体以及PFAS与甲状腺功能指标混合物的关联。

结果

PFAS混合物的脐带血浓度较高与新生儿TT4和FT4水平升高以及新生儿TSH浓度降低有关。将单一化学模型与多种化学模型结合使用时，PFOS，PFNA和PFUnDA与TT4水平升高相关，分别导致混合效应分别为46.4％，22.8％和16.7％。PFOS暴露与脐带血清FT4浓度呈正相关，对混合物的联合作用贡献28.9％。PFNA和PFHpA是导致新生儿TSH水平下降的最重要因素，分别占混合物的46.3％和45.0％。

结论

目前的发现表明脐带血清中单个PFAS及其混合物的甲状腺破坏。有必要进行额外的研究来探索潜在的生物学机制，尤其是对于PFAS混合物。