Received: 24 February 2021
Accepted: 29 August 2021
First Online: 5 September 2021
: The study was conducted in accordance with the guidelines established by the Declaration of Helsinki. Written informed consent was obtained from all participants prior to data collection. An information letter was sent to both parents and students at least 14 days before initiation of the data collection, and the schools were instructed to inform parents and adolescents about the study through established information channels. The information letter was approved by The Norwegian Centre for Research Data (NSD), which is the Data Protection Official for Research for all the Norwegian universities, university colleges and several hospitals and research institutes. Parents were given the opportunity to withdraw their children from participation. All data were collected anonymously and then analyzed by independent researchers who did not participate in the collection of the data. The overall legal responsibility for the Young Data survey is held by the NOVA research center of Norwegian Social Research, OsloMet, which provided ethical approval of the present study. This includes procedures for providing information about the study and collecting consent from participating adolescents and their parents. NOVA has also consulted the Regional Committee for medical and health research ethics and clarified the Young-Data was not obligated to seek approval from this committee.
: Not applicable.
: The authors have no conflicts of interest to declare.