Received: 11 October 2019
Accepted: 19 March 2020
First Online: 11 May 2020
Ethics approval and consent to participate
: The study was conducted in accordance with the Helsinki Declaration and approved by the Umeå Regional Ethics Board (Dnr 09-171 M). All participants provided written informed consent to participate.
: Not applicable.
: The authors declare that they have no competing interests.