Funding for this research was provided by:
The Danish foundation TrygFonden
Received: 24 October 2018
Accepted: 21 January 2019
First Online: 31 January 2019
Ethics approval and consent to participate
: According to Danish law, questionnaire and register-based studies do not need approval by ethical and scientific committees, nor informed consent [CitationRef removed, CitationRef removed]. All data has been de-identified by Statistics Denmark, will remain on the server of Statistics Denmark, and will be analysed through remote access by the researchers.
: Not applicable
: The authors declare that they have no competing interests.
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