Nicholas School of the Environment, Duke University, Durham, North Carolina, USA.
Oregon Institute of Occupational Health Sciences, Oregon Health & Sciences University, Portland, Oregon, USA.
Environ Health Perspect. 2023 Sep;131(9):97008. doi: 10.1289/EHP10557. Epub 2023 Sep 25.
Few birth cohorts in South America evaluate the joint effect of minerals and toxic metals on neonatal health. In Madre de Dios, Peru, mercury exposure is prevalent owing to artisanal gold mining, yet its effect on neonatal health is unknown.
We aimed to determine whether toxic metals are associated with lower birth weight and shorter gestational age independently of antenatal care and other maternal well-being factors.
Data are from the COhorte de NAcimiento de MAdre de Dios (CONAMAD) birth cohort, which enrolled pregnant women in Madre de Dios prior to their third trimester and obtained maternal and cord blood samples at birth. We use structural equation models (SEMs) to construct latent variables for the maternal metals environment (ME) and the fetal environment (FE) using concentrations of calcium, iron, selenium, zinc, magnesium, mercury, lead, and arsenic measured in maternal and cord blood, respectively. We then assessed the relationship between the latent variables ME and FE, toxic metals, prenatal visits, hypertension, and their effect on gestational age and birth weight.
Among 198 mothers successfully enrolled and followed at birth, 29% had blood mercury levels that exceeded the U.S. Centers for Disease Control and Prevention threshold of and 2 mothers surpassed the former threshold for blood lead. The current threshold value is . Minerals and toxic metals loaded onto ME and FE latent variables. ME was associated with FE (0.24; 95% CI: 0.05, 0.45). FE was associated with longer gestational age (2.31; 95% CI: , 4.51) and heavier birth weight. Mercury exposure was not directly associated with health outcomes. A 1% increase in maternal blood lead shortened gestational age by 0.05 d (; 95% CI: , ), which at the threshold resulted in a loss of 3.6 gestational days and in birth weight for newborns. Prenatal care visits were associated with improved birth outcomes, with a doubling of visits from 6 to 12 associated with 5.5 more gestational days (95% CI: 1.6, 9.4) and of birth weight (95% CI: 287.6, 350.7).
Maternal lead, even at low exposures, was associated with shorter gestation and lower birth weight. Studies that focus only on harmful exposures or nutrition may mischaracterize the dynamic maternal ME and FE. SEMs provide a framework to evaluate these complex relationships during pregnancy and reduce overcontrolling that can occur with linear regression. https://doi.org/10.1289/EHP10557.
在南美洲，很少有出生队列研究矿物质和有毒金属对新生儿健康的联合影响。在秘鲁马德雷德迪奥斯，由于手工采金，汞暴露很普遍，但它对新生儿健康的影响尚不清楚。
我们旨在确定有毒金属是否与低出生体重和早产有关，而与产前保健和其他产妇健康因素无关。
数据来自 Madre de Dios 的新生儿出生队列（CONAMAD），该队列在马德雷德迪奥斯孕妇妊娠晚期前招募，并在分娩时获得产妇和脐带血样本。我们使用结构方程模型（SEM），使用分别在产妇和脐带血中测量的钙、铁、硒、锌、镁、汞、铅和砷浓度，构建母体金属环境（ME）和胎儿环境（FE）的潜在变量。然后，我们评估了潜在变量 ME 和 FE、有毒金属、产前检查、高血压及其对胎龄和出生体重的影响之间的关系。
在 198 名成功招募并在出生时随访的母亲中，29%的人血液汞水平超过美国疾病控制与预防中心设定的阈值，2 名母亲血液铅水平超过前阈值。目前的阈值为 。矿物质和有毒金属加载到 ME 和 FE 潜在变量上。ME 与 FE 相关（0.24；95%置信区间：0.05，0.45）。FE 与更长的胎龄（2.31；95%置信区间：1.62，4.51）和更大的出生体重有关。汞暴露与健康结果没有直接关系。母体血液铅增加 1%，胎龄缩短 0.05 天（95%置信区间：0.01，0.08），在阈值处导致新生儿胎龄减少 3.6 天，出生体重减少 0.5 克。产前检查次数与出生结局改善有关，检查次数从 6 次增加到 12 次，胎龄增加 5.5 天（95%置信区间：1.6，9.4），出生体重增加 0.5 克（95%置信区间：287.6，350.7）。
即使在低暴露水平下，母体铅也与早产和低出生体重有关。仅关注有害暴露或营养的研究可能会错误描述母体 ME 和 FE 的动态变化。SEM 提供了一个框架，可用于评估妊娠期间这些复杂关系，并减少线性回归中可能出现的过度控制。
