Funding for this research was provided by:
National Institute on Drug Abuse (U01DA021525, R37 DA019829, R01DA031074, U01DA038886, DP2- DA040256-01)
Canadian Institutes of Health Research (MSH-141971)
Received: 2 August 2018
Accepted: 15 November 2018
First Online: 4 December 2018
Ethics approval and consent to participate
: All participants provided consent prior to enrollment, and all study sites received ethical approval from their local institutional review boards (IRBs) [CitationRef removed]. PRIMER was approved as previously described by the University of California, San Diego Human Research Protection Program, the University of British Columbia-Providence Health Care Research Ethics Board, and Universidad Xochicalco School of Medicine IRB.
: Not applicable.
: The authors declare that they have no competing interests.
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