Background

The relationship between mercury (Hg) exposure and thyroid hormones (THs) levels in the general population has been inconclusive. We conducted a random effects model meta-analysis to identify the association between Hg exposure and THs levels in the general population.

Methods

This meta-analysis were performed based on the PECO questions (P = general population; E =1ug/L Hg in blood and urine; C =1ug/L incremental increase on; and O = variation of THs levels). We searched four electronic databases including PubMed, Web of Science, Embase, and Cochrane Library for studies published on or before 20th July 2020. Prospective and cross-sectional studies that evaluated the association between Hg exposure and the levels of thyroid stimulating hormone (TSH), triiodothyronine (T3), thyroxine (T4), free triiodothyronine (FT3), and free thyroxine (FT4) were included. We also assessed aggregate risks for the reliability of the included studies.

Results

Initially, we retrieved 4889 articles. 18 studies met our inclusion criteria after screening and 13 articles were eligible to be included in the meta-analysis. The meta-analysis results suggest that blood Hg may be significantly associated with THs levels. The presence of Hg in blood may significantly increase the levels of TSH (β=0.55; 95%CI: 0.20,0.90; p < 0.001) and FT4 (β=0.47; 95%CI: 0.11,0.82; p < 0.001), with the opposite association in T4 (β=−0.02; 95%CI: 0.02, −0.01; p < 0.001). For the subgroup analysis, blood Hg was positively correlated with TSH levels in children and adolescents (β=0.62; 95%CI: 0.09, 1.15; p < 0.001) and FT4 levels in pregnant women (β=1.00; 95%CI: 0.99, 1.00; p < 0.001) respectively.

Conclusions

This meta-analysis indicates that exposure to Hg in blood could significantly corrrelate with the levels of TSH, T4, and FT4 in the general population. Therefore, it is crucial to control the use of Hg and strengthen protection of the thyroid.

中文翻译：

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汞暴露与甲状腺激素水平之间的关联：一项荟萃分析

背景

普通人群中汞（Hg）暴露与甲状腺激素（THs）水平之间的关系尚无定论。我们进行了一项随机效应模型的荟萃分析，以确定人群中汞暴露与THs水平之间的关联。

方法

这项荟萃分析是根据PECO问题进行的（P =普通人群； E = 1ug / L汞在血液和尿液中； C = 1ug / L的增量增加； O = THs水平的变化）。我们搜索了四个电子数据库，包括PubMed，Web of Science，Embase和Cochrane图书馆，以研究2020年7月20日或之前发表的研究。前瞻性和横断面研究评估了汞暴露与甲状腺刺激激素（TSH）水平之间的关联包括三碘甲状腺素（T3），甲状腺素（T4），游离三碘甲状腺素（FT3）和游离甲状腺素（FT4）。我们还评估了纳入研究的可靠性的总体风险。

结果

最初，我们检索了4889篇文章。筛选后有18项研究符合我们的纳入标准，有13篇文章符合纳入荟萃分析的条件。荟萃分析结果表明，血液中的汞可能与THs水平显着相关。血液中Hg的存在可能会显着增加TSH（β= 0.55; 95％CI：0.20,0.90; p  <0.001）和FT4（β= 0.47; 95％CI：0.11,0.82; p  <0.001）的水平，在T4中具有相反的关联（β= -0.02; 95％CI：0.02，-0.01; p  <0.001）。对于亚组分析，儿童和青少年的血液汞与TSH水平呈正相关（β= 0.62； 95％CI：0.09，1.15；p  <0.001），孕妇的FT4水平呈正相关（β= 1.00； 95％CI：0.99）。 ，1.00; p <0.001）。

结论

这项荟萃分析表明，血液中汞的暴露可能与普通人群中TSH，T4和FT4的水平显着相关。因此，控制汞的使用并加强对甲状腺的保护至关重要。