Funding for this research was provided by:
EkstraStiftelsen Helse og Rehabilitering (2012/2/0048 - 1220048001)
Text and Data Mining valid from 2018-10-01
Received: 15 November 2017
Accepted: 25 September 2018
First Online: 1 October 2018
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 institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.