Funding for this research was provided by:
National Institutes of Health (R01HD086013, 2R01HD041702)
Health Resources and Services Administration (R40MC27443, UJ2MC31074)
National Institute of Environmental Health Sciences (R03ES029594)
Received: 11 June 2019
Accepted: 7 October 2019
First Online: 28 November 2019
Ethics approval and consent to participate
: The study has been approved by the Institutional Review Boards of Boston Medical Center and Johns Hopkins Bloomberg School of Public Health. Written informed consent was obtained from each study child’s biological mother and assent from the study child.
: Not applicable.
: The authors declare that they have no competing interests.