Article History
Received: 26 November 2018
Accepted: 30 January 2019
First Online: 26 February 2019
Ethics approval and consent to participate
: Informed consent was obtained from all individual participants included in the study. The Data Protection Officer at Oslo University Hospital, Norway, gave their recommendation in processing health information for the study (#17/21472).
: Not applicable.
: The authors declare that they have no competing interests.
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