BACKGROUND Comprehensive examinations of placental metal concentrations and correlations with infant parameters are under-investigated. Chattanooga, Tennessee's consistently high incidence of low birth weight and potential for metal exposure provides an ideal opportunity to investigate potential correlations. OBJECTIVES To investigate the associations between a wide variety of metals in placental tissue and multiple infant parameters. METHODS A total of 31 elements were screened via ICP-MS in 374 individual placental samples. Of those, 14 were quantifiable in > 86% of the samples. We examined correlations between metal concentrations and infant parameters (birth weight, gestational age, birth weight centile, placental weight, birth length and head circumference). We fit multivariable regression models to estimate the covariate-adjusted associations of birth weight with ln-transformed concentrations of each of the 14 metals and used generalized additive models to examine nonlinear relationships. RESULTS Some of the strongest relationships with infant parameters came from several lesser-studied metals. Placental rhodium concentrations were negatively correlated with almost all infant parameters. In the fully adjusted regression model, birth weight was significantly associated with several metals. On an IQR (25th to the 75th percentile) basis, estimated changes in birthweight were: for cobalt (82.5 g, IQR=6.05 µg/kg, p = 0.006), iron (-51.5 g, IQR = 171800 µg/kg, p = 0.030), manganese (-27.2 g, IQR=152.1 µg/kg, p = 0.017), lead (-72.7 g, IQR=16.55 µg/kg, p = 0.004) and rhodium (-1365.5 g, IQR = 0.33 µg/kg, p < 0.001). Finally, a generalized additive model showed significant nonlinear relationships between birth weight and concentrations of Co and Rh. CONCLUSIONS Our comprehensive examination of placental metals illustrate many strong associations between lesser-studied metals and infant parameters. These data, in combination with our correlations of well-studied metals, illustrate a need to consider in utero exposure to a broad array of metals when considering fetal development.

中文翻译：

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田纳西州查塔努加的胎盘中必需，有毒和未充分研究的金属浓度及其与出生结局的关系。

背景技术对胎盘金属浓度及其与婴儿参数的相关性的综合检查尚待研究。田纳西州查塔努加（Chattanooga）出生体重偏低和金属暴露的可能性一直很高，这为研究潜在的相关性提供了理想的机会。目的探讨胎盘组织中多种金属与多种婴儿参数之间的关系。方法通过ICP-MS对374个胎盘样品进行筛选，共筛选出31种元素。其中有14种样品在> 86％的样品中可定量。我们检查了金属浓度与婴儿参数（出生体重，胎龄，出生体重百分位数，胎盘重量，出生长度和头围）之间的相关性。我们拟合多元回归模型以估计出生体重与14种金属中每种元素的ln转化浓度的经协变量调整的关联，并使用广义加性模型检查非线性关系。结果与婴儿参数最紧密的关系来自几种研究较少的金属。胎盘铑的浓度与几乎所有婴儿参数均呈负相关。在完全调整的回归模型中，出生体重与几种金属显着相关。在IQR（第25至第75个百分位数）的基础上，估计的出生体重变化为：钴（82.5 g，IQR = 6.05 µg / kg，p = 0.006），铁（-51.5 g，IQR = 171800 µg / kg，p = 0.030），锰（-27.2 g，IQR = 152.1 µg / kg，p = 0.017），铅（-72.7 g，IQR = 16.55 µg / kg，p = 0.004）和铑（-1365.5 g，IQR = 0.33 µg） /公斤，p <0.001）。最后，广义加性模型显示出生体重与Co和Rh的浓度之间存在显着的非线性关系。结论我们对胎盘金属的综合检查表明，研究较少的金属与婴儿参数之间存在许多强关联。这些数据，加上我们对金属元素的深入研究，说明在考虑胎儿发育时需要考虑子宫内多种金属的暴露。