Text and Data Mining valid from 2020-02-18
Received: 4 July 2019
Accepted: 21 January 2020
First Online: 18 February 2020
Ethics approval and consent to participate
: All participants provided written informed consent. For those participants who were aged below 18 years, their parents/caretakers signed additional written consent. The local ethics committee (KU Leuven, Nr. B32220107766) approved the study.
: Not applicable.
: The authors declare that they have no competing interests.