Text and Data Mining valid from 2018-07-18
Received: 6 April 2017
Accepted: 20 June 2018
First Online: 18 July 2018
Ethics approval and consent to participate
: All subjects had been selected consecutively; written informed consent from participants, the ethical approval was obtained from the regional ethics committee in Göteborg, Sweden (697–11) and conducted according to the Declaration of Helsinki.
: 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.