Date: June 16, 2014
FOR IMMEDIATE RELEASE
National Children’s Study Has Great Potential to Expand Understanding of Children’s Health and Well-Being, But Key Design Elements Need Further Development for Study to Be Successful
WASHINGTON -- While the National Children’s Study (NCS) could add immensely to knowledge about children’s health and development, and while the study’s proposed design has several strengths, the design needs stronger scientific rationale and further development of several key aspects such as sampling and measurement strategies, says a new congressionally mandated report from the National Research Council and Institute of Medicine.
The NCS was authorized by the Children’s Health Act of 2000 and is being implemented by a dedicated program office in the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD). The committee that wrote the report conducted a comprehensive review to assess whether the NCS, which would collect a broad range of environmental exposure data on about 100,000 children from birth or before birth to age 21, is likely to produce scientifically sound results that are applicable to the general U.S. population and appropriate subpopulations.
The committee endorsed a number of aspects of the proposed design, including:
· the use of a national equal probability sample for a large cohort of births;
· the concept of the study as a data collection platform with a focus on health and development guided by exemplar scientific hypotheses;
· the inclusion of siblings born within the four-year window; and
· the collection and storage of biological and environmental samples to permit subsequent analysis.
One important part of the design -- the plan to recruit half of the children in the probability sample prenatally and the other half at the time of birth -- was not endorsed by the committee. Due to the scientific importance of prenatal exposures on child development, the report recommends recruiting almost all of the births prenatally (except when mothers do not seek prenatal care) and as early in pregnancy as possible.
It is feasible to have close to 100 percent prenatal recruitment for about 95,000 children in the probability sample by dropping the planned 10,000 “convenience samples,” according to the committee’s cost analysis, as these samples would either increase costs substantially or be of less scientific value than the main sample. In the current design, half of the convenience sample births would come from first-time mothers recruited prior to their child’s conception, while the other half might come from populations exposed to natural disasters, siblings born outside the four-year recruitment window, and additional members of disadvantaged groups.
“Although other countries such as Japan, Norway, and the U.K. have performed large-scale national birth cohort studies, the U.S. National Children’s Study would be the most comprehensive study of child health and development in the world,” said committee chair Greg Duncan, distinguished professor of education at the University of California, Irvine. “If carried out successfully, the data collection program has the capacity to take advantage of emerging innovations in the biological, social-psychological, and environmental sciences, maximizing the chances for discoveries to address potentially preventable conditions that cause child morbidity.”
The report offers further recommendations regarding data collection measures and schedule, analysis of health disparities, and cost structure. Because of insufficient information, however, the committee could not assess several other aspects of the study design that were part of its charge, such as cost-effectiveness, the choice to use hospitals as primary sampling units instead of geographic areas as in early pilot testing, details of sampling and recruitment strategies, schedule and content of data collection in early waves, and extent of data collection burden on respondents, among others.
Due to this limited information and lack of scientific justification for many of the NCS design decisions, the report recommends that NICHD enhance the scientific expertise of the NCS program office, by recruiting and contracting with experts in relevant fields from within the National Institutes of Health, other federal agencies, and outside of government.
In addition, NICHD should establish an authoritative multidisciplinary oversight structure to review the program office’s decisions, as well as establish a mechanism for regular, independent outside review by a qualified organization or a study section like those in NIH.
The NCS, which is currently in pilot testing, has a tentative 2015 start date for the main study. If implemented, the recommendations to enhance the scientific expertise, oversight, and outside review of the NCS could result in delays; however, the committee stressed that the quality, utility, and cost-effectiveness of NCS will ultimately be enhanced.
The study was sponsored by the U.S. Department of Health and Human Services. The National Academy of Sciences, National Academy of Engineering, Institute of Medicine, and National Research Council make up the National Academies. They are private, independent nonprofit institutions that provide science, technology, and health policy advice under a congressional charter granted in 1863. The National Research Council is the principal operating arm of the National Academy of Sciences and the National Academy of Engineering. For more information, visit www.national-academies.org. A committee roster follows.
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Pre-publication copies of The National Children’s Study 2014: An Assessment are available from the National Academies Press on the Internet at http://www.nap.edu or by calling 202-334-3313 or 1-800-624-6242. Reporters may obtain a copy from the Office of News and Public Information (contacts listed above).
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NATIONAL RESEARCH COUNCIL
Division of Behavioral and Social Sciences and Education
Committee on National Statistics
INSTITUTE OF MEDICINE
Board on Children, Youth, and Families
Panel on the Design of the National Children’s Study and
Implications for the Generalizability of Results
Greg J. Duncan1 (chair)
Distinguished Professor of Education
School of Education
University of California
Dean B. Baker
Chief, Division of Occupational and Environmental Medicine
Center for Occupational and Environmental Health
University of California
Paul P. Biemer
Distinguished Fellow in Statistics
Research Triangle Park, N.C.
Barbara Lepidus Carlson
Associate Director of Statistics
Mathematica Policy Research Inc.
Ana V. Diez Roux2
Distinguished Professor of Epidemiology and Dean
Drexel University School of Public Health
Professor and Chair
Statistics Department, and
Director of Survey Research Center
Oregon State University
Marie C. McCormick2
Summer and Esther Feldberg Professor of Maternal and Child Health
Department of Social and Behavioral Sciences
Harvard School of Public Health
Sara S. McLanahan1
William S. Tod Professor of Sociology and Public Affairs
Office of Population Research
Professor of Obstetrics and Gynecology
University of Texas Medical Branch
S. Lynne Stokes
Professor of Statistical Science
Department of Statistical Science
Southern Methodist University
Pediatrics and Environmental Medicine
New York University School of Medicine
New York City
1Member, National Academy of Sciences
2Member, Institute of Medicine