Funding for this research was provided by:
Helse Sør-Øst RHF (2015090)
Helse Vest (911891, 911938)
Received: 20 February 2020
Accepted: 29 May 2020
First Online: 10 June 2020
Ethics approval and consent to participate
: All procedures performed on human participants were in accordance with the ethical standards of the institutional and national research committee (Regional Committees for Medical Research Ethics - South East Norway, 2014/158/REK sør-øst) and with the 1964 Helsinki declaration and its later amendments. All participants gave a written informed consent to take part in the study.
: Not applicable.
: Lars Christian Haugli Bråten, Elina Iordanova Schistad, Ansgar Espeland, Per Martin Kristoffersen, Anne Julsrud Haugen, Gunn Hege Marchand, Nils Vetti, Are Hugo Pripp, Thomas Istvan Kadar, Jan Sture Skouen, Margreth Grotle, Lars Grøvle, John-Anker Zwart, Jens Ivar Brox and Kjersti Storheim declare that they have no conflict of interest.