Funding for this research was provided by:
Helse Sør-Øst RHF (grant number 2015106)
First Online: 7 November 2019
Compliance with Ethical Standards
: The authors declare that they have no conflict of interest.
: All procedures performed in studies involving human participants were in accordance with the ethical standards of the national research committee (REK 2015/2169) and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
: Informed consent was obtained from all individual participants included in the study.