Thomas Shari, Arbuckle Tye E, Fisher Mandy, Fraser William D, Ettinger Adrienne, King Will
Department of Public Health Sciences, Queen's University, Kingston, Ontario, Canada.
Population Studies Division, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Canada.
Environ Res. 2015 Jul;140:430-9. doi: 10.1016/j.envres.2015.04.018. Epub 2015 May 15.
Lead, mercury, cadmium and arsenic are some of the most common toxic metals to which Canadians are exposed. The effect of exposure to current low levels of toxic metals on fetal growth restriction is unknown.
The aim of this study was to examine relationships between exposure to lead, mercury, cadmium and arsenic during pregnancy, and risk of small for gestational age (SGA) birth.
Lead, mercury, cadmium and arsenic levels were measured in blood samples from the first and third trimesters in 1835 pregnant women from across Canada. Arsenic species in first trimester urine were also assessed. Relative risks and 95% confidence intervals were estimated using log binomial multivariate regression. Important covariates including maternal age, parity, pre-pregnancy BMI, and smoking, were considered in the analysis. An exploratory analysis was performed to examine potential effect modification of these relationships by single nucleotide polymorphisms (SNPs) in GSTP1 and GSTO1 genes.
No association was found between blood lead, cadmium or arsenic and risk for SGA. We observed an increased risk for SGA for the highest compared to the lowest tertile of exposure for mercury (>1.6 µg/L, RR=1.56.; 95% CI=1.04-2.58) and arsenobetaine (>2.25 µg/L, RR=1.65; 95% CI=1.10-2.47) after adjustment for the effects of parity and smoking. A statistically significant interaction was observed in the relationship between dimethylarsinic acid (DMA) levels in urinary arsenic and SGA between strata of GSTO1 A104A (p for interaction=0.02). A marginally significant interaction was observed in the relationship between blood lead and SGA between strata of GSTP1 A114V (p for interaction=0.06).
These results suggest a small increase in risk for SGA in infants born to women exposed to mercury and arsenic. Given the conflicting evidence in the literature this warrants further investigation in other pregnant populations.
铅、汞、镉和砷是加拿大人接触到的一些最常见的有毒金属。目前接触低水平有毒金属对胎儿生长受限的影响尚不清楚。
本研究的目的是探讨孕期接触铅、汞、镉和砷与小于胎龄儿（SGA）出生风险之间的关系。
对来自加拿大各地的1835名孕妇孕早期和孕晚期的血样中的铅、汞、镉和砷水平进行了测量。还评估了孕早期尿液中的砷形态。使用对数二项式多变量回归估计相对风险和95%置信区间。分析中考虑了包括产妇年龄、产次、孕前体重指数和吸烟等重要协变量。进行了一项探索性分析，以研究GSTP1和GSTO1基因中的单核苷酸多态性（SNP）对这些关系的潜在效应修正作用。
未发现血铅、镉或砷与SGA风险之间存在关联。在调整产次和吸烟的影响后，我们观察到汞暴露最高三分位数组（>1.6μg/L，RR=1.56；95%CI=1.04-2.58）和砷甜菜碱暴露最高三分位数组（>2.25μg/L，RR=1.65；95%CI=1.10-2.47）相比最低三分位数组，SGA风险增加。在GSTO1 A104A不同基因型组中，尿砷中的二甲基砷酸（DMA）水平与SGA之间的关系存在统计学显著的交互作用（交互作用p值=0.02）。在GSTP1 A114V不同基因型组中，血铅与SGA之间的关系存在边缘显著的交互作用（交互作用p值=0.06）。
这些结果表明，接触汞和砷的女性所生婴儿的SGA风险略有增加。鉴于文献中的证据相互矛盾，这值得在其他孕妇群体中进一步研究。
