Received: 5 April 2019
Accepted: 16 July 2019
First Online: 17 August 2019
Ethics approval and consent to participate
: Ethics approval was sought for the COSNEON study from the Medical Ethics Review Committee of the University of Groningen (reference number METc 2018.624). No formal review of the protocol is deemed necessary. Participation in COSNEON is optional. The approach will be via social media, posters, and flyers, but active registration by the participants is necessary. Informed consent will be obtained from all study participants.
: Not applicable.
: The authors declare that they have no competing interests.