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Giant longitudinal child study put on hold

The National Children's Study (NCS), which aims to follow the health of 100,000 babies until they turn 21, is now on hold following an assessment by the Institute of Medicine (IOM) and National Research Council (NRC). The IOM/NRC report notes several flaws with the study's design and oversight. In response, National Institutes of Health (NIH) Director Francis Collins decided to halt the NCS until possible fixes can be evaluated.

The National Children's Study was authorized by Congress 14 years ago as part of the Children's Health Act of 2000. The goal of the NCS is to "examine the effects of the environment and genetics on child health and development." Environment is broadly defined in the study and includes a child's "physical, chemical, biological, and social and cultural environments." The study plans to include 100,000 children from across the United States. Having this many participants, who are selected to be representative of the entire country, will hopefully give the study enough statistical power to determine whether exposure to particular environmental features is associated with particular health outcomes.

Like the study itself, the IOM/NRC review of the study was congressionally mandated. The panel of experts that examined the plan approved of several aspects of the study, including the overall concept and hypotheses driving the study, the statistical method for recruiting a representative population of children, the inclusion of siblings born within four years, and the plan to collect various biological and environmental samples.

While supporting the overall ideas behind the study, the panel also found parts of the study plan problematic. One particular sticking point was the proposal to recruit half of the children prenatally and the other half after birth. The report suggests changing the study design so that as many children as possible enter the study before birth (and as early in pregnancy as possible). This is because of an abundance of data showing that the prenatal environment can have significant effects on child development. The report also suggests changes to the data collection schedule, how health disparities will be analyzed, and the study's cost structure.

The panel's largest concern, however, was insufficient information about the study's design and a "lack of scientific justification for many of the NCS design decisions." Without these details, the panel said it was unable to determine if the study was scientifically sound or cost-effective. Thus, the report recommends establishing an "authoritative multidisciplinary oversight structure to review the program office's decisions."

Collins' response to the report suggests that the NCS may be on thin ice. In his statement, he questioned the feasibility of the study "in the face of significant budget constraints" and even asked whether new methods could be used instead of the proposed large-scale longitudinal study.

The main NCS study had a tentative start date of 2015 (a smaller pilot study began last year). Given the skewering the study received in the IOM/NRC report and the subsequent response by Collins, it seems likely that the date will be pushed back, assuming the study is not canceled altogether.

Hopefully, the NCS—with help from external experts—will be quickly revamped. No other study currently underway in the United States or elsewhere has the potential to provide so much information about the role of the environment on child development and health. However, the fates of other longitudinal studies suggest that the NCS will need committed and long-term financial support (likely on the order of a few billion dollars) to track these babies until their 21st birthdays. In the current funding climate, that might be a hard sell.