Funding for this research was provided by:
U.S. National Library of Medicine (LM012849)
Received: 4 November 2019
Accepted: 29 January 2020
First Online: 12 February 2020
Ethics approval and consent to participate
: This study was approved by the University of Maryland Institutional Review Board. All data used in the analysis were publicly available, and all data related to individual persons were in aggregate.
: Not applicable.
: The authors declare that they have no competing interests.