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Article History

Received: 7 April 2021

Accepted: 11 August 2021

First Online: 18 October 2021

Change Date: 24 February 2022

Change Type: Update

Change Details: The OA funding note has been added. The article has been updated to rectify the error.

Declarations

:

: Informed consent was obtained from adolescents (≥ 12 years), and the assent was given from younger children, in addition to parental informed consent. Ethical approval was obtained from local ethic committees of each study center in accordance with the ethical standards of the Declaration of Helsinki (1964) and its later amendments as follows- Belgium: Ethics Committee of the Gent University Hospital, 15/10/2007, ref.: No. EC UZG 2007/243 and 19/02/2013, No. B670201316342; Cyprus: Cyprus National Bioethics Committee, 12/07/2007, ref.: No. EEBK/EM/2007/16 and 21/Feb/2013, No.EEBK/ETI/2012/33; Estonia: Tallinn Medical Research Ethics Committee (TMREC), 14/06/2007, ref.: No. 1093 and 17/January 2013, No. 128; Germany: Ethic Commission of the University of Bremen, 16/01/2007 and 11/12/2012; Hungary: Medical Research Council, 21/Jun/2007, ref.: 22–156/2007-1018EKU and 18/12/2012, 4536/2013/EKU; Italy: Ethics Committee of the Local Health Authority (ASL) in Avellino, 19/06/2007, ref.: No. 2/CE and 18/Sep/2012, No. 12/12; Spain: Ethics Committee for Clinical Research of Aragon (CEICA), 20/06/2007, ref.: No. PI07/13 and 13/Feb/2013, No. PI13/0012; Sweden: Regional Ethics Research Board in Gothenburg, 30/07/2007, ref.: No. 264–07 and 10/Jan/2013, No. 927–12).

: Not applicable.

: The authors declare that they have no competing interests.