Funding for this research was provided by:
European Union Horizon 2020 research and innovation program (689043)
Received: 13 September 2021
Accepted: 4 January 2022
First Online: 8 February 2022
: The <scp>self</scp>BACK trial was approved by the Danish Data Protection Agency and regional ethics committees in Denmark and Norway. All potential participants provided written informed consent before enrolment into the trial.
: Not applicable.
: All authors declare no competing interests.