Funding for this research was provided by:
Folkhälsomyndigheten (SU FV-6.1.2-1511-19)
Received: 8 March 2021
Accepted: 8 July 2021
First Online: 26 July 2021
: The Swedish Health Behaviour in School-aged Children (HBSC) data contain no information on personal identification and the questionnaire is completed anonymously by the students. Therefore, no formal approval from an ethical review board was required. Informed consent was obtained from the students who participated. Due to the procedure of anonymous completion of the questionnaire, active written or oral consent was not applicable. Parents/guardians were informed by schools that the study was going to take place and those who did not want their children to participate were asked to inform the school to opt out.
: Not applicable.
: The authors declare that they have no competing interests.