<p>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.</p>

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