Article History
Received: 14 September 2020
Accepted: 30 November 2020
First Online: 14 December 2020
Ethics approval and consent to participate
: The regional ethical review board in Gothenburg, Sweden, approved the study (Dnr 009–04 and Dnr T240–08 for the amendment concerning the extension of the cohort). All participants gave there written consent to take part in the study.
: Not applicable.
: The authors declare that they have no competing interests.