Hagen, Knut http://orcid.org/0000-0003-2111-8895
Stovner, Lars Jacob
Nilsen, Kristian Bernhard
Kristoffersen, Espen Saxhaug
Winsvold, Bendik Slagsvold
Article History
Received: 12 June 2019
Accepted: 11 September 2019
First Online: 26 September 2019
Ethics approval and consent to participate
: This study was approved by the Regional Committee for Medical and Health Research Ethics, the Faculty of medicine, mailbox 8905, 7491 Trondheim. The approval number was #2018/2422/Rek Midt. The participants have given written informed consent.
: Not applicable.
: The authors declare that they have no competing interests.