Received: 11 December 2019
Accepted: 19 May 2020
First Online: 24 May 2020
Ethics approval and consent to participate
: The need for ethical approval of the study was waived by the Regional Ethics Committee of the South-East Health Region, Norway (REC no. 2013/602). Participants were given written and oral information about the study, and signed an informed consent form. No incentives were offered to participants.
: Not applicable.
: The authors declare that they have no competing interests.