Funding for this research was provided by:
Health and Care Research Wales (HF-2016-1164)
Medical Research Council (MC/PC/17211, MC/PC/17212)
Received: 13 January 2020
Accepted: 25 June 2020
First Online: 2 July 2020
Ethics approval and consent to participate
: Ethical approval for this study was obtained from Cardiff University’s School of Social Sciences Research Ethics committee (SREC/2190). This study was approved by the Health Information Research Unit’s independent Information Governance Review Panel (project 0808). School level written consent was first obtained from schools who wished to participate; parents/guardians were then informed about the survey via two standard school communication channels (i.e. letter, email or text message), where they were given the opportunity to withdraw their child via a process of ‘opt-out’ consent; and student written consent to take part in the survey was provided at the start of the survey and consent for data linkage was provided at the end.
: Not applicable.
: The authors declare that they have no competing interests.