Funding for this research was provided by:
Universitetet i Tromsø (250110)
Text and Data Mining valid from 2018-04-25
Received: 6 May 2016
Accepted: 8 April 2018
First Online: 25 April 2018
Change Date: 14 March 2019
Change Type: Correction
Change Details: .
Ethics approval and consent to participate
: The Norwegian Social Science Data Services (NSD) gave their approval (Reference number 34221), while the Regional Committee for Medical Research Ethics judged that the project did not require approval (REK North Reference number 2013/131), corresponding to the Norwegian regulations for ethical research practice and ethical principles stated in the Helsinki declaration. After receiving oral and written information about the design and goals of the study, all participants gave their voluntary approval for participation by signing an informed consent form.
: The authors declare that they have no competing interests.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.