Funding for this research was provided by:
Academy of Finland (285439, 287288, 288038, 315816)
The ministry of Education and Culture in Finland
The Ministry of Social Affaire and Health
The Juho Vainio foundation
Signe ja Ane Gyllenbergin Säätiö
Päivikki ja Sakari Sohlbergin Säätiö
Medicinska Understödsföreningen Liv och Hälsa
Received: 25 February 2020
Accepted: 26 November 2020
First Online: 9 January 2021
Ethics approval and consent to participate
: The adolescents’ participation in the study was voluntary and based on informed consent. Consent for publication was also obtained. In addition, each preschools headmaster independently decided whether to participate in the study.University of Helsinki Ethical Review Board in the Humanities and Social and Behavioural Sciences approved our study on 24th February 2015 (#6/2015).
: Authors declare that they have no conflict of interest.