IN UTERO PCB, PESTICIDE & METAL EXPOSURE & CHILDHOOD COGNITION

本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。具体地说，将研究宫内暴露于常见环境污染物--多氯联苯(PCBS)、二氯二苯基二氯乙烯(DDE)、甲基汞(MeHg)和铅(Pb)--在一般环境中的水平对神经发育的影响。此外，还将研究出生后铅暴露的神经发育毒性。这项研究将受益于广泛的信息，这些信息可用于790名儿童的既定队列，这些儿童的母亲居住在马萨诸塞州多氯联苯污染的港口(和超级基金地点)附近的社区。这些孩子出生时就获得了多项宫内暴露措施的生物标记物，并在生命的前六个月进行了详细的发育评估。这项拟议的研究将通过三个主要假设对这些达到学龄的儿童进行后续评估。子宫内低水平的多氯联苯、DDE、甲基汞和铅暴露以及出生后铅暴露与：(1)对记忆和成功学习所需的其他技能的长期毒性。(2)学习成绩测验评估的学习受损，与一般认知能力相比，成绩是一个打击期望。(3)慢性行为障碍，特别是与注意力障碍有关的行为障碍。这项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布)与感兴趣的发展结果的关系。这一假设的一个推论是评估与多氯联苯污染地点的接近是否与不利的发育影响相关，而不依赖于个人暴露措施。作为这项研究的一部分，将对500名6至8岁的儿童进行记忆、学习、语言技能、一般认知和注意力的评估；标准化的成就测试；以及教师和父母的行为评估。这些评估的结果将与脐带血和/或母乳中的多氯联苯、滴滴涕和铅的水平、学龄前儿童的血铅水平和围产期母亲的头发汞水平进行比较。这项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的学习至关重要，并在当前美国人口特有的暴露水平上做到这一点。

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.