IN UTERO PCB, PESTICIDE & METAL EXPOSURE & CHILDHOOD COGNITION

该项目的主要目的是研究低水平宫内毒素暴露对学龄儿童记忆和学习的影响。具体来说，宫内暴露于常见环境污染物——多氯联苯（PCBs）、二氯二苯二氯乙烯（DDE）、甲基汞（MeHg）和铅（Pb）——在一般环境中出现的水平的神经发育影响将被研究。出生后铅暴露的神经发育毒性也将被研究。这项研究将受益于广泛的信息，这些信息可用于已建立的队列，其中790名儿童的母亲居住在马萨诸塞州一个受多氯联苯污染的港口（和超级基金场址）附近的社区。在这些儿童出生时获得了多种子宫内暴露测量的生物标志物，并在生命的前六个月进行了详细的发育评估。本研究将根据三个主要假设，对这些达到学龄的儿童进行跟踪评估。子宫内低水平的PCB、DDE、MeHg和Pb暴露和产后Pb暴露与：(1)对记忆和其他成功学习所必需的技能的长期毒性有关。(2)成绩测试评估的学习障碍，与一般认知能力相比，成绩低于预期。(3)慢性行为障碍，特别是与注意力障碍有关的行为障碍。该研究的第二个假设将是评估社区和相关背景变量（例如，社区内的收入和种族分配）与感兴趣的发展结果的关系。这一假设的一个推论是评估靠近多氯联苯污染地点是否与独立于个人暴露措施的不良发育影响有关。作为这项研究的一部分，对记忆、学习、语言技能、一般认知和注意力的评估；标准化成绩测试；教师和家长对500名6到8岁儿童的行为进行评估。这些评估结果将与脐带血清和/或母乳中多氯联苯、二苯醚和铅的水平进行比较；学龄前血铅水平；以及围产期产妇头发中的汞含量。本研究的最终目标是解决这些暴露与儿童能力和行为之间关系的不确定性，这些能力和行为对成功学习至关重要，并以当前美国人口的暴露水平为特征进行研究。

The main objective of this project is to study the effects of low-level intrauterine toxin exposures on memory and learning in school age children. Specifically, the neurodevelopmental effects of intrauterine exposures to common environmental contaminants-polychlorinated biphenyls (PCBs), dichlorodiphenyl dichloroethene (DDE), methylmercury (MeHg), and lead (Pb)-- at levels occurring in the general environment will be studied. The neurodevelopmental toxicities of postnatal Pb exposure will also be studied. The study will benefit from extensive information that is available for an established cohort of 790 children born to mothers residing in communities adjacent to a PCB- contaminated harbor (and Superfund site) in Massachusetts. Biomarkers of multiple in utero exposure measures were obtained for these children at birth, and detailed developmental assessments were performed during the first six months of life. The proposed study will be conducted as a follow- up evaluation of these children as they achieve school age with three major hypotheses. Low-level in utero PCB, DDE, MeHg, and Pb exposures and postnatal Pb exposures are associated with: (1) Long-term toxicity to memory and other skills necessary for successful learning. (2) Impaired learning as assessed by achievement testing, and achievement that is blow expectation compared with general cognitive ability. (3) Chronic behavioral disturbances, in particular those associated with attention disorders. A secondary hypothesis of the study will be to assess the relationship of neighborhood and related contextual variables (e.g., income and racial distribution within neighborhoods) with the developmental outcomes of interest. A corollary to this hypothesis is assessment of whether proximity to the PCB-contaminated site is associated with adverse developmental effects independent of individual exposure measures. As part of this research, assessments of memory, learning, language skills, general cognition, and attentions; standardized achievement testing; and teacher and parental behavioral assessments will be obtained for 500 six-to eight-year olds. Results of these assessments will be compared with cord serum and/or breast milk levels of PCB, DDE, and Pb; preschool blood Pb levels; and peripartum maternal hair mercury levels. The ultimate goals of this study are to address uncertainties regarding the relationship of these exposures with childhood abilities and behaviors that are critical to successful learning and to do so at exposure levels characteristic of the current U.S. population.