Fig. 1: Trial profile.

A total of 2297 subjects were screened. 1151 students were recruited for intervention group sequence and 1146 students were recruited for control group sequence. Some students have dropped out during the study for the indicated reasons. Finally, the analysis included 794 participants (387 boys and 407 girls) in the intervention group, and 592 participants (299 boys and 293 girls) in the control group.