Text and Data Mining valid from 2020-01-30
Received: 16 May 2019
Accepted: 15 January 2020
First Online: 30 January 2020
Ethics approval and consent to participate
: The participants received oral and written information and provided written informed consent before participating in the study. The study was approved by the Norwegian Regional Committee for Medical Research Ethics South-East-B (REK reference 2017/350).
: Not applicable.
: The authors declare that they have no competing interests.