Funding for this research was provided by:
Universitetet i Bergen
Helse Vest Regionalt Helseføretak
Received: 25 June 2018
Accepted: 28 February 2019
First Online: 18 March 2019
Change Date: 6 April 2020
Change Type: Correction
Change Details: Following the publication of our article , we have become aware of one error in the exclusion criteria, inconsistencies in Figure 1 and Figure 2, and a typo in the reference list.
Ethics approval and consent to participate
: The Regional Committee for Medical and Health Research Ethics, region North, has approved the study, reference number 2015/2189. All the important protocol modifications are reported to the Regional Committee for Medical and Health Research Ethics for approval, and will be reflected in the scientific reporting of results. The project coordinators provide participants with written and oral information about the study before enrolment. All participants have signed informed consent before enrolment in the study, and the Regional Committee for Medical and Health Research Ethics regulates the use of all data.
: Not applicable.
: The authors declare that they have no competing interests.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.