Received: 11 February 2020
Revised: 28 April 2020
Accepted: 20 May 2020
First Online: 20 June 2020
Compliance with ethical standards
: The authors declare that they have no conflict of interest.
: We use pre-existing data (scientific use files of the “German Health Interview and Examination Survey for Children and Adolescents” KiGGS study). This research involved human participants. All procedures were in accordance with the ethical standards of the institutional and/or national research committee.
: Informed consent was obtained from all participants included in the study.