Lessons learned for the National Children's Study from the National Institute of Environmental Health Sciences/U.S. Environmental Protection Agency Centers for Children's Environmental Health and Disease Prevention Research

Environmental Health Perspectives, Oct, 2005 by Carole A. Kimmel, Gwen W. Collman, Nigel Fields, Brenda Eskenazi

Plans for the National Children's Study are to enroll pregnant women as early in pregnancy as possible and to enroll a subset of the cohort before conception. Current plans are to follow 100,000 births to adulthood (21 years of age), with collection of data on exposures and outcomes at points throughout the study. Two major goals of the study are to use the longitudinal design as a way to link exposures with outcomes that occur at different points in time (i.e., exposure may precede the resulting outcome by months or years) and to explore interactions among various factors, including genetic traits. The general design and administrative structure are described by the National Children's Study Interagency Coordinating Committee (2003) and the Study Plan (National Children's Study 2005).

Planning for this large study began in mid-2000 with the initiation of a number of methods development studies, particularly the development of less burdensome and less costly exposure assessment methods (U.S. EPA 2004a). Other efforts have included laboratory studies on noninvasive procedures for analysis of biomarkers of exposures and outcomes (Rockett et al. 2002), development of comparable measures that could be administered in children and laboratory animal models enabling further exploration of exposure-outcome links in animal studies (Sharbaugh et al. 2003), and field studies using focus groups to explore recruitment and retention issues. A number of reviews and white papers have been developed, including an evaluation of advanced technology for capturing data, a review of the leading hypotheses of the effects of environmental factors on children's health outcomes, and a review of the leading sampling strategies for consideration in the study. In addition, a resource database on biomarkers of exposures and outcomes was developed (U.S. EPA 2004b). More recently, a number of workshops have been organized to explore and refine the measures that might be included in the protocol for the study. A complete listing of workshops, meetings, and reports can be found at the National Children's Study website (2005).

Because of the research being conducted by the Children's Centers, a good deal of expertise and specialized knowledge have already been developed that can be particularly valuable to the development of protocols for the National Children's Study. As detailed below, much of the work of the original eight centers was on pesticide exposures and neurodevelopment, and air pollution and asthma. The four additional Children's Centers are focusing on developmental disabilities, particularly autism spectrum disorders, and the impact of various environmental pollutants on learning and behavior.

These and other exposures and outcomes have been established as priorities for the National Children's Study (Table 1). Thus, the Children's Centers have experience in several of the priority focus areas that should provide valuable input to the design of the National Children's Study.