Received: 14 April 2020
Accepted: 9 June 2020
First Online: 9 July 2020
Ethics approval and consent to participate
: This study was approved by the Norwegian Regional Committee for Medical and Health Research Ethics (ref. 2017/8130) and the Norwegian Data Protection Authority at Oslo University Hospital. All participants provided written consent to participate in the study.
: Not applicable.
: The authors declare that they have no competing interests.