Funding for this research was provided by:
Stiftelsen för Kunskaps- och Kompetensutveckling (20160040)
Received: 26 September 2018
Accepted: 17 December 2018
First Online: 5 January 2019
Ethical approval and consent to participate
: The data in this study were retrieved from two larger projects with cross-sectional and cohort designs, respectively. The Stockholm regional ethics committee approved both projects, Dnr 2016/796–31 and Dnr 2014/1526–32, respectively. All participants signed a written informed consent form prior to participating.
: Not applicable.
: The author(s) declare(s) that they have no competing interests.
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