Document is current

Article History

Received: 10 February 2020

Revised: 9 September 2020

Accepted: 11 September 2020

First Online: 6 October 2020

Compliance with ethical standards

:

: The authors declare that there is no conflict of interest regarding the publication of this article.

: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee (Ethical Committee of the University of São Paulo (Protocol Number: 1.719.856); Ethical Committee of Ministry of Health in Brazil (Protocol Number 2.014.816)) and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. Informed consent was obtained from all individual participants included in the study.

: All participating schools took part voluntarily. At each school, a meeting was required with parents of students of the selected class, in order to present the project and obtain their consent. Furthermore, a letter and a folder with information on the project were sent to the principals of the schools to be delivered to the parents. Parents’ refusal could be informed to the school board, or to the coordination, or yet to the research team, either by phone, e-mail or in person, during the meeting. For those adolescents whose parents did not refuse participation, a questionnaire was delivered in class for them to fill in individually. Only students whose parents did not refuse the participation and who additionally did agree themselves participated. No information that could identify the student or the school was retained. In the questionnaire, schools and students are identified by a number, so that anonymity cannot be disrespected.