Funding for this research was provided by:
National Institutes of Health (N01-AG-1-2100, HHSN27120120022C, ZIAEY00401, R01 AG027012, R01 EY017362)
Received: 5 December 2018
Accepted: 20 December 2018
First Online: 8 January 2019
Ethics approval and consent to participate
: Written informed consent was obtained from all participants. The study was approved by the Icelandic National Bioethics Committee and the Institutional Review Boards for the National Institute on Aging and the Johns Hopkins School of Medicine.
: Not applicable.
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