Text and Data Mining valid from 2020-04-16
Received: 2 January 2019
Accepted: 11 March 2020
First Online: 16 April 2020
Ethics approval and consent to participate
: The study was carried out according to the Declaration of Helsinki. According to Danish law, approval by the Ethics Committee and written informed consent are not required in questionnaire-based projects. Participating schools were informed and advised to inform the parents about the data collection. It was stated clearly that participation was voluntarily. Additional information is available at the National Committee on Health Research Ethics’ webpage in the “Act on Research Ethics Review of Health Research Projects” § 14,2. Here the rules regarding consent are stated, and only trials are mandatory to collect parental consent, not questionnaire-based studies like this. Available from ExternalRef removed.
: Not applicable.
: The authors declare that they have no competing interests.