Received: 19 June 2019
Accepted: 3 January 2020
First Online: 14 January 2020
Ethics approval and consent to participate
: The study was approved by the Regional Ethical Review Board of Uppsala, Sweden (ref: 2016/191 [2019–02077]). The participants gave written informed consent, and were informed that participation was on a voluntary basis and that they could withdraw from the study at any time. Confidentiality was guaranteed.
: Not applicable.
: The authors declare that they have no competing interests.