LEAD MOBILIZATION DURING PREGNANCY AND LACTATION

描述(取自应用程序) 来自病例报告和铅同位素比率研究的证据表明 储存在骨骼中的铅在怀孕和哺乳期被动员起来， 使母亲，特别是发育中的胎儿和婴儿处于危险之中 铅中毒。胎盘对铅是完全渗透的，而铅是 存在于母乳中。钙的摄入可以防止铅的吸收。 为了研究骨骼铅在体内被活化的假说 怀孕，也许更重要的是在哺乳期，我们建议 重复性血铅和骨铅测定的干预研究 墨西哥莫雷洛斯环境铅暴露水平较高的妇女人口。 妇女将随机接受钙和维生素补充剂，钙 没有维生素补充剂，或者只有维生素补充剂。我们会 同时跟踪一组未怀孕的女性。我们假设 当铅在怀孕和哺乳期间被动员时，母亲、胎儿和 婴儿的血铅水平将会增加，母亲的骨铅水平将会上升 减少。我们将比较骨铅和全血铅水平 怀孕后两周、六周从同一名妇女那里获得的测量数据 产后6个月和12个月。骨铅水平将通过X射线测量 荧光。我们将检测骨转换的分子生物标记物以 评估是否同时发生骨重建和铅动员。我们 假设怀孕期间骨铅水平将会下降，并进一步 在哺乳期，由于骨铅动员的结果。对照组大鼠 非妊娠妇女将使我们能够比较骨铅的自然历史 在没有怀孕和哺乳的情况下的变化。获得的血铅水平 在每一个孩子同时为母亲S产后进行评估 提供有关母亲将循环铅转移给孩子的信息。 为了评估基因与环境的相互作用，我们将检查多态 在ALA-D中，血色素沉着症基因和维生素D受体影响铅 从骨头里释放出来。我们假设接受钙补充剂的女性 将有较少的领导调动，从而较少转移到他们的发展 孩子。我们还将评估钙加维生素补充剂是否比 比单独的钙更有保护作用。这项研究将在莫雷洛斯进行， 墨西哥的人口有很高的环境铅暴露， 主要是通过使用铅釉陶瓷，在那里妇女有 母乳喂养率高。因此，我们将能够比较骨铅 哺乳期间的动员与怀孕期间的动员。这个 调查应该为潜在的健康提供重要的见解 慢性环境铅暴露对孕期和哺乳期的影响 妇女、发育中的胎儿和婴儿通过母乳喂养，以及 对预防方法的见解。

DESCRIPTION (Taken from application) Evidence from case reports and studies of lead isotope ratios suggest that lead stored in the skeleton is mobilized during pregnancy and lactation, placing the mother and, in particular, the developing fetus and infant at risk of lead poisoning. The placenta is fully permeable to lead, and lead is present in breast milk. Calcium intake may protect against lead absorption. To investigate the hypothesis that skeletal lead is mobilized during pregnancy, and perhaps more importantly during lactation, we propose an intervention study with repeated measures of blood and bone lead in a population of women in Morelos, Mexico with high environmental lead exposure. Women will be randomized to receive calcium and vitamin supplements, calcium without vitamin supplements, or vitamin supplements alone. We will simultaneously follow a control group of non-pregnant women. We hypothesize that as lead is mobilized during pregnancy and lactation, maternal, fetal and infant blood-lead levels will increase, and maternal bone-lead levels will decrease. We will compare bone- and whole blood-lead levels prior to pregnancy with measurements obtained from the same women at two weeks, six months and twelve months postpartum. Bone-lead levels will be measured by X-Ray Fluorescence. We will examine molecular biomarkers of bone turnover to assess whether concurrent bone remodeling and lead mobilization occurs. We hypothesize that bone-lead levels will decrease during pregnancy, and further during lactation as a result of bone-lead mobilization. The control group of non-pregnancy women will allow us to compare the natural history of bone-lead changes in the absence of pregnancy and lactation. Blood-lead levels obtained in each child at the same time as the mother s postpartum evaluations will provide information about maternal transfer of circulating lead to the child. To assess gene-environment interactions, we will examine whether polymorphisms in ALA-D, the hemochromatosis gene and the Vitamin D receptor influence lead release from bone. We hypothesize that women receiving calcium supplements will have less lead mobilization and thus less transfer to their developing child. We will also assess whether calcium plus vitamin supplements is more protective than calcium alone. This study will be undertaken in Morelos, Mexico where the population has high environmental lead exposure, predominantly through the use of lead-glazed ceramics, and where women have high rates of breast-feeding. Thus we will be able to compare bone-lead mobilization during lactation with that which occurs during pregnancy. The investigation should provide important insights into the potential health effects of chronic environmental lead exposure to pregnant and lactating women, developing fetuses, and infants through breast feeding, as well as insights into approaches for prevention.