Received: 6 July 2018
Accepted: 22 March 2019
First Online: 15 April 2019
Ethics approval and consent to participate
: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Ethical approval was obtained from the Medical Ethical Committee of VU University Medical Center Amsterdam (Twisk: 12/151).All parents and guardians of children in the sample provided a written informed consent.
: Participants consented to have all anonymised data available for publication.
: The authors declare that they have no competing interests.
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