The Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) served as the lead agency for the National Children's Study (NCS or Study), a longitudinal cohort study that was designed to examine the effects of environmental and genetic influences on the health and development of children. Environment was broadly defined to include biological, physical, chemical, and social/cultural influences on children's health and development. Priority outcomes included obesity, diabetes, and physical development; injuries; asthma; pregnancy-related outcomes; child development and mental health; the drivers of health disparities and identifying beneficial health effects. The goal of the Study was to provide information that would ultimately lead to improvements in the health, development, and well-being of children.
The National Children's Study Vanguard Study was a pilot study for a large-scale epidemiological cohort study of children and their mothers and fathers. Measures were to be taken from pre-pregnancy until the children reached adulthood. The Vanguard Study tested a variety of sampling schemes, measurement forms and protocols, and information management systems. At the recommendation of the National Institutes of Health Advisory Committee to the Director, the Study was closed on December 12, 2014. Nonetheless, data from the Vanguard Study can be used to address a number of research questions in pediatric and environmental health.
The Vanguard Study enrolled 5,726 participants at 40 locations around the country. It collected data in multiple phases: Initial Vanguard Study (2009-2010), Alternate Recruitment Substudy (Minimal and Expanded Visits; 2010-2012), Provider-Based Sampling Substudy (2012-2014), and Post-Recruitment Follow-Up (2014). It also evaluated five different recruitment strategies: one in the initial phase, three in the second phase, and one more in the third phase.
The initial phase of recruitment for the Vanguard Study (Initial Vanguard Study) began in 2009. Data collectors canvassed neighborhoods to locate and enroll women who were pregnant or were likely to become pregnant. After a year, fewer participants had been enrolled than was expected. The second phase of recruitment (Alternative Recruitment Substudy) began in 2010. This phase compared three recruitment strategies to assess their effectiveness. By 2012, one method (Provider-Based Recruitment) was clearly the most efficient. The third phase (Provider-Based Sampling) began in 2012. This phase used the most efficient recruitment strategy from the second phase and enhanced it through the use of an altered sampling strategy.
During the second and third recruitment phases, data were gathered using one of two methods: minimal data collection or expanded data collection. Minimal visits consisted solely of questionnaire administration. Expanded visits consisted of questionnaire administration and one or more of the following: physical measures, biospecimens, and environmental samples. In June 2014, NCS received approval to use expanded data collection for all remaining Study visits (Post-Recruitment Follow-Up) and continued to follow up with all participants eligible for a visit until the study closed in December 2014. Detailed participant information was collected in the first phase and between June and December 2014, but abbreviated versions of questionnaires were used during the second and third phase.
The applications created for exploration of the Vanguard Study data are described below. All data used in the applications are from data collected during 2012, including Vanguard Study data.
The summary application is a graphical tool that allows user to understand variable relationships within the 2012 NCS Vanguard Study dataset. The goal of this application is to be an entry point to the data at the county level. To explore these data, sort a variable by clicking on the category of interest in the legend above the variable plot.
The comparisons tool links additional 2012 data sources to the Vanguard Study data to enhance the insights gained from the study. This application graphically links information together from the Vanguard Study and other data sources that produce measures relevant to the NCS, i.e. measures that could describe a child's environment in its totality, including both the physical (e.g. air quality metrics, number of supermarkets in the vicinity) and social (e.g. percent of county in the Women, Infants, and Children (WIC) program) determinants of health. The main goal of this tool is to facilitate the uncovering of relationships between Vanguard Study variables and those from multiple extant datasets at the county level.
The extant sources used in Comparisons comes from Vanguard Study Center profiles develop by NORC. The User's Guide for the profiles is available. The file layout for the 2012 profile data is available.