Funding for this research was provided by:
Helse Sør-Øst RHF (2015056)
Received: 14 November 2017
Accepted: 31 January 2018
First Online: 27 March 2018
Ethics approval and consent to participate
: Approved by the Norwegian Regional Committees for Medical and Health Research Ethics, reference number 2014/1989. We obtained informed, written consent from all participants in the study.
: Not applicable.
: The authors declare that they have no competing interests.
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