Holstein, Bjørn E.
Damsgaard, Mogens Trab
Madsen, Katrine Rich
Pedersen, Trine Pagh
Toftager, Mette
Article History
Received: 19 April 2021
Revised: 31 August 2021
Accepted: 1 September 2021
First Online: 16 September 2021
Declarations
:
: There is no formal agency for approval of questionnaire-based surveys in Denmark. Therefore, we asked the school board as the parents’ representative, the headmaster, and the students’ council in each of the participating schools to approve the study. The Danish Data Protection Authority has granted acceptance for the 2014 survey (Case No. 2013–54-0576) and the 2018 survey (Case 10 622, University of Southern Denmark).
: The participants received oral and written information that participation was voluntary, and that data were treated confidentially. The study complies with national standards for data protection.
: Not applicable.
: The authors declare no competing interests.