National Children's Study Vanguard Study Formative Research Study (NCS)

The National Children's Study (NCS) is a multi-year prospective epidemiological study tasked with identifying a nationally representative sample of 100,000 children and following them from pregnancy through age 21 to study environmental impacts on growth, development, and health. Determination of NCS enrollee ancestry is important for assessing the diversity of study enrollees and for examining the effect of ancestry on various health outcomes. We estimated the genetic ancestry of a convenience sample of 641 parents enrolled at the 7 original NCS Vanguard sites by analyzing 29,972 markers on exome arrays, using the participants of the 1000 Genomes Project (1KG) super populations (e.g. European, East Asian) as reference populations, and compared this to self-reported ethnicity and race. Self-reported ethnicity and race agreed with predicted super population in 98.9% of individuals. NCS individuals identified as Asian by self-report had genetic ancestry of either South Asian or Asian groups, while those reporting as either Hispanic White or Hispanic Other had similar genetic ancestry. Of the 33 individuals who self-reported as Multiracial or Non-Hispanic Other, 11 (33%) matched the South Asian and Asian groups, while these groups were less represented in the other reported categories (27/609, 4.4%). Our data suggest that self-reported ethnicity and race categories have some limitations in accurately capturing this information for Hispanic and South Asian populations. Overall, our data indicate that despite the complexity of the U.S. population, individuals know their ancestral origins and that self-reported ethnicity and race is a reliable indicator of genetic ancestry.]]>
T1 Mother InterviewT1 Father Interview646 blood samples from parents enrolled in the NCS were obtained from the NCS biorepository. The samples were collected from 7 different NCS Vanguard Centers across the United States, including Brookings County, SD (which also enrolled participants from Yellow Medicine County, MN, Pipestone County, MN and Lincoln County, MN), Duplin County, NC, Montgomery County, PA, Orange County, CA, Queens, NY, Salt Lake County, UT and Waukesha County, WI. Of the 646 samples, 346 were from mothers and 300 were from fathers; 360 individuals were paired enrollees (mother and father), and the remaining individuals were a single enrolled parent (166 mothers, 120 fathers). There was one sample (mother) for which no DNA was isolated, resulting in 645 of 646 samples from which DNA could successfully be isolated. Of these, 642 were successfully run on the HumanExome BeadChip. One individual was subsequently removed due to high genome-wide similarity to another sample, for a total of 641 samples.]]>
The major goal of the NCS, authorized by the U.S. Congress through the Child Health Act of 2000, is to discover and characterize environmental exposures that contribute to causation of disease or, conversely, that enhance children's health (Children's Health Act of 2000, Public Law 106-310 Sec. 1004). The pilot phase of the NCS, known as The Vanguard Study, is a small scale study, using convenience sampling, being conducted to evaluate the feasibility, acceptability, and costs of the methods that will be used to carry out the main study. The Vanguard study began in 2009 with a total of 7 locations, or Vanguard Centers, and grew to include 40 sites. In this study, we examined whether self-reported ethnicity and race accurately assesses the genetic ancestry of participants in The National Children's Study. DNA from 641 NCS-enrolled parents from 7 Vanguard sites was assayed using exome arrays and 29,972 markers were used for ancestry estimation.]]>