Funding for this research was provided by:
Dutch Organization of Health Research (525001005.)
Received: 26 November 2017
Accepted: 27 July 2018
First Online: 15 August 2018
Ethics approval and consent to participate
: The studies were approved by the Medical Ethics Committee of the University Medical Center Utrecht, the Netherlands. (METC number: 14–332/c and 14–118/m). All participants and the parents of participants under 18 years of age provided their informed written consent. Studies were conducted in accordance with the Helsinki Declaration.
: Not applicable
: Saskia J te Velde, Kristel Lankhorst, Maremka Zwinkels, Olaf Verschuren, Tim Takken and Janke de Groot have no competing interests.
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