National Children's Study

国家儿童研究（NCS）是一项前瞻性纵向队列研究，研究环境暴露和基因环境相互作用对儿童健康和发育的个体和综合影响，研究对象是在美国出生的约10万名儿童的代表性样本。这些孩子将从出生前一直被跟踪到21岁。这项研究的重要性和及时性基于许多因素，包括过去的经验表明，环境暴露（如怀孕期间接触酒精和幼儿期接触铅）对儿童健康和发育的深远影响；与成人相比，儿童对环境暴露的特殊脆弱性；已知的持续接触，如非持久性农药的普遍水平或幼儿每天接触媒体的时间；以及环境对这种高影响条件的贡献或原因的证据。全国健康调查的主要目的是调查环境暴露（化学、生物、物理、社会心理）以及基因-环境相互作用对妊娠结局、儿童健康和发育以及成人疾病前兆的单独和综合影响。这项研究的独特之处在于，它关注的是怀孕初期（以及之后）的环境暴露，以及计划暴露的广度和结果测量。NCS响应2000年儿童健康法案的国会授权，即NICHD和一个联邦机构联盟计划并开展一项关于环境暴露对儿童影响的纵向研究。国家信息中心将采用全国概率抽样方法来选择地点和参与者进行研究。抽样设计采用多阶段聚类方法。在第一阶段，从美国所有县中随机选择105个地点（一般对应单个县）。其中7个地点作为初始地点或先锋地点，参与NCS的试点阶段。由于研究的重点包括评估妊娠早期暴露的影响，孕妇及其伴侣和育龄妇女构成了最初的登记目标人群。数据收集将采用面对面接触和远程收集方法相结合的方式，例如电话、电脑或邮寄问卷。预期的接触频率（面对面或远程）大约是每三个月一次，直到一岁，每六个月一次，直到五岁，之后每年一次。对于参加研究的儿童样本，还将访问儿童保育和学校环境，以收集环境样本和观察数据。预期的生物标本包括母亲和儿童的血液、尿液、头发和指甲剪；父亲的血液，尿液和头发；分娩时/前后采集的脐带血、脐带和胎盘组织及胎便；阴道拭子和母亲的母乳。预期的环境样本包括空气、灰尘、土壤、食物和水。全国儿童研究已经在美国各地的30个研究地点开始招募。这项研究是美国有史以来对儿童健康进行的最大的长期研究。

The National Children's Study (NCS) is prospective longitudinal cohort study of the individual and combined effects of environmental exposures and gene environmental interactions on child health and development in a representative sample of approximately 100,000 children born in the United States. The children will be followed from before birth until age 21. The importance and timeliness of this study are based on many factors, including past experiences demonstrating profound effects of environmental exposures, such as exposures to alcohol during pregnancy and to lead in early childhood on child health and development; the special vulnerabilities of children to environmental exposures compared to adults; known ongoing exposures, such as prevalent levels of non-persistent pesticides or hours of media exposure per day in young children; and evidence for environmental contributions or causes to such high-impact conditions . The primary aim of the NCS is to investigate the separate and combined effects of environmental exposures (chemical, biological, physical, psychosocial) as well as gene-environment interactions on pregnancy outcomes, child health and development, and precursors of adult disease. Unique features of the study include its focus on environmental exposures at the earliest stages of pregnancy (as well as thereafter) and the breadth of planned exposure and outcome measurements. The NCS responds to the Congressional mandate of the Children's Health Act of 2000, that the NICHD and a consortium of federal agencies plan and conduct a longitudinal study of the impacts of environmental exposures on children. The NCS will employ a national probability sampling approach to select locations and participants for conduct of the study. The sampling design utilizes a multistage clustered approach. In the first stage, 105 locations (generally corresponding to single counties) were randomly selected from all U.S. counties. Seven of the locations serve as the initial or Vanguard Locations, participating in the pilot phase of the NCS. Because the focus of the study includes assessment of the impact of exposures that occur early in pregnancy, both pregnant women and their partners, and women of childbearing age, comprise the initial target population for enrollment. Data will be collected in combinations of face-to-face contacts and remote collection methods, e.g., telephone, computer, or mail-in questionnaires. The expected frequency of contact (face-to-face or remote) is approximately every three months through age one, every six months through age five years and annually thereafter. For a sample of children enrolled in the study, visits will also be made to child care and school settings for collection of environmental samples and observational data. Anticipated biologic specimens include blood, urine, hair, and nail clippings from mothers and children; blood, urine, and hair from fathers; cord blood, umbilical cord and placental tissues, and meconium collected at/around the time of delivery; vaginal swabs, and breast milk from mothers. Anticipated environmental samples include air, dust, soil, food, and water. The National Children's Study has initiated recruitment at 30 study locations around the United States. The Study is the largest long-term study of children's health ever conducted in the United States.