Environmental As, pregnancy, and children's health

值得注意的是，很少有人知道慢性无机砷（InAs）暴露在孕妇和儿童的健康后果，通常被认为是最容易受到环境暴露。砷化铟是动物中已知的致畸剂，特别是在不能将其甲基化为甲基胂酸（MMA）和二甲基胂酸（DMA）的物种中。我们已经确定了一个地区的孟加拉国（Sonargaon）的饮用水含有独特的广泛的浓度的砷。我们建议进行这些研究，将测试有关的健康影响和代谢的InAs在孕妇和儿童的假设。在2001年，我们将通过回顾性研究过去的怀孕结果，在大约2000名妇女，研究砷InAs暴露之间的关系，通过测量饮用水和尿中的砷进行评估，后来自然流产和死产。在2002年和2003年，我们将招募大约100名妊娠12-20周的妇女，以检验这一假设，即通过给予多种维生素或多种维生素+叶酸可以促进As甲基化。这项随机试验将检查在提供这些补充剂之前和之后InAs，MMA和DMA的尿排泄。第三，在同一孕妇中，我们将描述分娩时母体和脐带InAs，MMA和DMA之间的关系，我们还将检查血浆同型半胱氨酸（叶酸和B12状态的标志物）与InAs，MMA和DMA之间的关系。最后，在2004年和2005年，我们将分别对6岁和10岁的儿童进行横断面研究，以检查InAs暴露与选定的健康结果生物标志物之间的关联。

Remarkably little is known about the health consequences of chronic inorganic arsenic (InAs) exposure in pregnant women and children, typically perceived to be the most vulnerable to environmental exposures. InAs is a known to teratogen in animals, particularly in species that are inefficient in methylating it to monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA). We have identified a region of Bangladesh (Sonargaon) where drinking water contains a uniquely wide range concentrations of InAs. We propose to conduct these studies which will test hypotheses concerning the health effects and metabolism of InAs in the pregnant women and children. In year -01, through a retrospective study of past pregnancy outcomes in approximately 2000 women, we will examine the relations between InAs exposure, assess through measurements of drinking water and urinary As, and later spontaneous abortion and stillbirth. In years -02 and -03, we will recruit approximately 100 women at 12-20 weeks of gestation to test the hypothesis that As methylation can be facilitated through the administration of multi-vitamins, or multi-vitamins + addition folate. This randomized trial will examine urinary excretion of InAs, MMA and DMA before and after the provision of such supplements. Third, among the same pregnant women, we will describe at delivery the relationships between maternal and umbilical cord InAs, MMA and DMA; we will also examine the relation between plasma homocyst(e)ine (a marker of folate and B12 status) and InAs, MMA and DMA. Finally, in years -04 and -05, we will conduct cross-sectional studies of children aged-6 and 10-years, respectively, to examine association between InAs exposure and selected biomarkers of health outcomes.