Received: 25 April 2019
Accepted: 29 April 2019
First Online: 16 May 2019
Ethics approval and consent to participate
: The study protocol was submitted to the Danish Ethical Committee (case number: H-15000641). Protocols for survey studies are exempted from ethical approval in Denmark, but approval from the Danish Protection Agency was required and subsequently obtained (identification number: 2007-58-0015). The study was performed in accordance with the Declaration of Helsinki and written informed consent was obtained from participants.
: Not applicable.
: The authors declare that they have no competing interests.
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