Funding for this research was provided by:
Youth Team of Humanistic and Social Science of Shandong University (20820IFYT1902)
Received: 6 June 2022
Accepted: 14 November 2022
First Online: 25 November 2022
: Data from GYTS and NYTS are de-identified and publicly available. All GYTSs and NYTSs were approved by the corresponding National Ethics Committee, and all students/guardians provided verbal consent.
: Informed consent was obtained from all participants and data from the GYTS and the NYTS are de-identified.
: Bo Xi is a member of the BMC Medicine editorial board. None of the authors, including Bo Xi, had a role in the peer review or handling of this manuscript. The authors, other than Bo Xi, declare that they have no competing interests.