Département de Santé Environnementale et Santé au Travail, Chaire d'analyse et de Gestion des Risques Toxicologiques and Institut de Recherche en Santé Publique de l'Université de Montréal (IRSPUM), Faculty of Medicine, Université de Montréal, P.O. Box 6128, Main Station, Montreal, Quebec H3C 3J7, Canada.
Département de Santé Environnementale et Santé au Travail, Chaire d'analyse et de Gestion des Risques Toxicologiques and Institut de Recherche en Santé Publique de l'Université de Montréal (IRSPUM), Faculty of Medicine, Université de Montréal, P.O. Box 6128, Main Station, Montreal, Quebec H3C 3J7, Canada.
Chemosphere. 2014 Mar;98:1-17. doi: 10.1016/j.chemosphere.2013.10.006. Epub 2013 Nov 5.
The impact polychlorinated biphenyl (PCB) exposure on thyroid status in pregnant women and newborns was investigated in various epidemiological studies, but findings show inconsistencies, and differences in biological indicators of exposure between studies limits comparison of results. The aim of this research was to use a procedure previously developed to standardize PCB biological concentration data between published studies to perform a systematic analysis of associations between PCB exposure and thyroid hormones (THs) (total and free T3 and T4) or thyroid stimulating hormone (TSH) in pregnant women and newborns. Biological concentrations from nineteen studies were expressed in total PCB equivalent per kg of lipids in maternal plasma (μg PCBMPEQ kg(-1) lipids). Systematic analysis of the "standardized biological concentration-thyroid parameters" relationship was conducted through the application of methodological criteria in both pregnant women and newborns. Standardization of PCB levels and application of methodological criteria led to assign higher confidence to ten of the reviewed studies. Among the retained studies in pregnant women, only one reported a significant association between PCBs and total T3 levels, but no association were observed when circulating TSH and free T4 levels were used to assess thyroid function. Regarding the association between prenatal PCB exposure and thyroid status in newborns, a lack of significant association was consistently obtained in the retained studies assigned an overall high confidence. The weight of evidence of a significant impact of PCB exposure on TSH and TH levels at the described biological levels in pregnant women and newborns (mean<1000 μg PCBMPEQ kg(-1) lipids) appears low according to this systematical analysis.
多氯联苯（PCB）暴露对孕妇和新生儿甲状腺功能的影响在各种流行病学研究中得到了调查，但研究结果显示存在不一致性，并且研究之间生物暴露指标的差异限制了结果的比较。本研究的目的是使用先前开发的一种程序来标准化发表研究之间的 PCB 生物浓度数据，以对 PCB 暴露与孕妇和新生儿甲状腺激素（THs）（总 T3 和 T4 以及促甲状腺激素（TSH））之间的关联进行系统分析。19 项研究的生物浓度以母体血浆中总 PCB 等效物（μg PCBMPEQ kg(-1) 脂质）表示。通过在孕妇和新生儿中应用方法学标准，对“标准化生物浓度-甲状腺参数”关系进行了系统分析。PCB 水平的标准化和方法学标准的应用使得对审查的研究中有 10 项研究的可信度更高。在孕妇中保留的研究中，只有一项研究报告了 PCBs 与总 T3 水平之间存在显著相关性，但当使用循环 TSH 和游离 T4 水平评估甲状腺功能时，没有观察到相关性。关于产前 PCB 暴露与新生儿甲状腺功能的关联，在保留的研究中，一致获得了缺乏显著相关性的结果，这些研究被赋予了总体高可信度。根据这一系统分析，在描述的生物水平（平均<1000μg PCBMPEQ kg(-1) 脂质）下，PCB 暴露对 TSH 和 TH 水平有显著影响的证据权重似乎较低。
