Biological markers of fetal lead exposure at each stage of pregnancy
Biological markers of fetal lead exposure at each stage of pregnancy
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DOI：
10.1080/15287390600630195
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发表时间：
2006-10-01
影响因子：
2.6
通讯作者：
Hu, Howard
中科院分区：
文献类型：
--
作者：
Lamadrid-Figueroa, Hector;Tellez-Rojo, Martha Maria;Hu, Howard
有人认为血浆铅（Pb）代表通过胎盘的循环铅的比例。全血铅水平，传统的测量循环铅的方法，可能不能充分反映血浆铅水平。本研究的目的是评估一组孕妇全血和血浆铅之间的关系。研究人员从1997年到1999年在墨西哥城招募了237名孕妇。采用电感耦合等离子体质谱法测定妊娠12、24和34周全血和血浆铅浓度。数据分析采用混合效应回归模型。发现血浆和全血铅水平呈指数关系，并随妊娠阶段的变化而显著改变。这种关联在妊娠中期比妊娠早期更强，在妊娠晚期进一步增强。该模型预测，在给定全血铅值的情况下，随着妊娠进展，全血铅水平大于110 μ g/L时血浆铅水平升高，而血铅水平小于100 μ g/L时血浆铅水平不升高。这些发现可能是由于妊娠期间的生理变化，如血细胞比容降低、红细胞铅结合能力饱和、骨吸收或肠道吸收增加。总的来说，这些数据表明，在母亲血铅水平升高的情况下，发育中的胎儿因母亲血浆铅水平升高而暴露于铅的风险可能比从全血铅水平预测的要大。
It has been suggested that plasma lead (Pb) represents the fraction of circulating Pb that crosses the placenta. Whole-blood Pb levels, the conventional method for measuring circulating Pb, may not adequately reflect plasma Pb levels. The objective of this study was to assess the relationship between whole-blood and plasma Pb in a cohort of pregnant women. A group of 237 pregnant women, recruited in Mexico City from 1997 to 1999, was studied. whole-blood and plasma lead concentrations were evaluated at 12, 24, and 34 wk of gestation by inductively coupled plasma-mass spectrometry. Data were analyzed using a mixed-effects regression model. An exponential relationship was found between plasma and whole-blood Pb levels and significant modification of the association by stage of pregnancy. The association was stronger in the second trimester relative to the first, and it further increased in the third trimester. The model predicts increased plasma Pb levels for a given whole-blood Pb value as pregnancy advances for whole-blood Pb levels greater than similar to 110 mu g/L, but not for blood Pb levels less than 100 mu gL. These findings could be due to physiologic changes during pregnancy, such as decreasing hematocrit, saturation of red cell Pb binding capacity, and increased bone resorption or intestinal absorption. Collectively, these data suggest that at elevated maternal blood Pb levels the developing fetus may be at greater risk of Pb exposure from increased maternal plasma Pb than otherwise predicted from whole-blood Pb levels.