Funding for this research was provided by:
Text and Data Mining valid from 2018-06-14
Received: 17 October 2017
Accepted: 1 June 2018
First Online: 14 June 2018
Ethics approval and consent to participate
: The study was approved by the Regional Committee for Medical and Health Research in Norway (REK) (approval no. 2014/647). Participants provided written informed consent.
: The authors declare that they have no competing interests.
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