Funding for this research was provided by:
Centers for Disease Control and Prevention (U01DP006266)
National Institute on Aging (5-T35-AG038047-07)
National Institute of Arthritis and Musculoskeletal and Skin Diseases (P60 AR062760)
Received: 17 July 2018
Accepted: 19 October 2018
First Online: 10 November 2018
Ethics approval and consent to participate
: The study was approved by the Institutional Review Board of the University of North Carolina at Chapel Hill and the Centers for Disease Control and Prevention. All study participants provided written informed consent.
: Not applicable
: The authors declare that they have no competing interests.
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