Background

The infant microbiome contributes to health status across the lifespan, but environmental factors affecting microbial communities are poorly understood, particularly when toxic and essential elements interact.

Objective

We aimed to identify the associations between a spectrum of other early-postnatal nutrient or toxic elemental exposures measured and the infant gut microbiome.

Methods

Our analysis included 179 six-week-old infants from the New Hampshire Birth Cohort Study. Eleven elements were measured in infant toenail clippings. The gut microbiome was assessed using 16S rRNA V4-V5 hypervariable region targeted sequencing. Multivariable zero-inflated logistic normal regression (MZILN) was used to model the association between element concentrations and taxon relative abundance. To explore interactive and nonlinear associations between the exposures and specific taxa we employed Bayesian Kernel Machine Regression (BKMR). Effect modification by delivery mode, feeding mode, peripartum antibiotic exposure, and infant sex was assessed with stratified models.

Results

We found a negative association between arsenic and microbial diversity in the full population that was accentuated among infants exposed to peripartum antibiotics. Arsenic, cadmium, copper, iron, lead, manganese, nickel, selenium, tin, and zinc were each associated with differences in at least one taxon in the full study population, with most of the related taxa belonging to the Bacteroides and Lactobacillales. In stratified analyses, mercury, in addition to the other elements, was associated with specific taxa. Bifidobacterium, which associated negatively with zinc in MZILN and BKMR models, had a quadratic association with arsenic concentrations. These associations varied with the concentration of the other element.

Conclusions

Early postnatal toxic and nutrient elemental exposures are associated with differences in the infant microbiome. Further research is needed to clarify the whether these alterations are a biomarker of exposure or if they have implications for child and lifelong health.

中文翻译：

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美国纵向出生队列中的营养-有毒元素混合物和早期产后肠道微生物组。

背景

婴儿微生物群对整个生命周期的健康状况都有影响，但影响微生物群落的环境因素却知之甚少，特别是当有毒元素和必需元素相互作用时。

客观的

我们的目的是确定测量的一系列其他产后早期营养素或有毒元素暴露与婴儿肠道微生物群之间的关联。

方法

我们的分析包括来自新罕布什尔州出生队列研究的 179 名六周大婴儿。在婴儿剪下的脚趾甲中测量了十一种元素。使用 16S rRNA V4-V5 高变区靶向测序评估肠道微生物组。多变量零膨胀逻辑正态回归（MZILN）用于模拟元素浓度和分类单元相对丰度之间的关联。为了探索暴露与特定分类单元之间的交互和非线性关联，我们采用了贝叶斯核机器回归（BKMR）。使用分层模型评估分娩方式、喂养方式、围产期抗生素暴露和婴儿性别的效果修正。

结果

我们发现，在整个人群中，砷与微生物多样性之间存在负相关性，这种负相关性在暴露于围产期抗生素的婴儿中尤为突出。砷、镉、铜、铁、铅、锰、镍、硒、锡和锌均与整个研究群体中至少一种分类群的差异相关，其中大多数相关分类群属于拟杆菌属和乳酸杆菌目。在分层分析中，除了其他元素外，汞还与特定的分类群相关。双歧杆菌在 MZILN 和 BKMR 模型中与锌呈负相关，与砷浓度呈二次相关。这些关联随着其他元素的浓度而变化。

结论

产后早期有毒元素和营养元素的暴露与婴儿微生物组的差异有关。需要进一步的研究来澄清这些改变是否是暴露的生物标志物，或者它们是否对儿童和终生健康有影响。