Received: 24 April 2019
Accepted: 23 August 2019
First Online: 30 September 2019
Ethics approval and consent to participate
: The study protocol was approved by the Medical Ethics Committee of the University Medical Centre of Groningen (reference number NL48614.042.14). Written consent was obtained from all participants.
: Written consent to publish was obtained from all participants.
: Dagmar E. Wortmann, Carina G. Boven, Jurjen Schortinghuis, Arjan Vissink, and Gerry M. Raghoebar declare that they have no competing interests.