Received: 22 January 2018
Accepted: 21 February 2019
First Online: 7 March 2019
Ethics approval and consent to participate
: Informed consent in writing was obtained from all participants in this study. Studies from which data have been included in the current study were approved by local medical ethics committees. The original study protocol for sample 1 was approved by the CMO Arnhem/Nijmegen (2013/368); and the protocol for studies involving sample 2 and 3 by the local ethics commission (ACPO 21.03/16) of the HAN University of Applied Sciences. The authors certify that they have no affiliation with or financial involvement in any organisation or entity with a direct financial interest in the subject matter or materials in the article.
: Not applicable.
: The author(s) declare that they have no competing interest. No external funding was received for this work.
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