Funding for this research was provided by:
Received: 29 October 2018
Accepted: 20 December 2018
First Online: 9 January 2019
Ethics approval and consent to participate
: Approval from the Danish Data Protection Agency (2007-58-0015) was obtained. Approval from the regional ethics committee was not required (H-4-2014-FSP).
: Not applicable.
: The authors declare that they have no competing interests.
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