Funding for this research was provided by:
National Institutes of Health (R24TW008878)
Received: 27 September 2017
Accepted: 28 February 2018
First Online: 6 March 2018
Ethics approval and consent to participate
: Ethical approval for the study was obtained from the Health Research Ethics Committee of the University of Nigeria Teaching Hospital (NHREC/05/01/2008B-F-WA00002458-1RB00002323). Written assent was obtained from the students after a detailed explanation of the study objectives, procedures, risks and benefits. Written informed consent was also obtained from the principals of the selected schools, who acted as the legal guardians of the students, as was done in previous GYTS studies in Nigeria. The Ethics Committee approved consent from school principals on behalf of parents.
: Not applicable
: The authors declare that they have no competing interests.
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