Funding for this research was provided by:
Received: 20 February 2019
Accepted: 4 July 2019
First Online: 12 July 2019
Ethics approval and consent to participate
: The study protocol and data handling procedures were approved by the Regional Ethical Review Board of Northern Sweden, Umeå (Dnr 2013/332/31) and the Regional Ethics Examination Board in Gothenburg approved the current study in 2017 (Dnr 276–17). All study participants provided written informed consent, and the study was conducted in accordance with the Declaration of Helsinki.
: Not applicable.
: The authors declare that they have no competing interests.