Text and Data Mining valid from 2018-08-13
Received: 5 March 2018
Accepted: 31 July 2018
First Online: 13 August 2018
Ethics approval and consent to participate
: The study has been approved by the Regional Committee for Medical and Health Research Ethics (REK 2009/2536). Written informed consent to participate was obtained from all participants.
: Not applicable.
: The authors declare that they have no competing interests.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.