Funding for this research was provided by:
The Danish Research council
The Faculty of Health at Aarhus University
Received: 25 April 2019
Accepted: 10 October 2019
First Online: 2 December 2019
Ethics approval and consent to participate
: Samples were obtained under protocols approved by the Stanford University Institutional Review Board. All study participants gave written consent to participate.
: All study participants gave verbal consent for publication.
: The authors declare that they have no competing interests.