RESULTS
The study obtained a total of 8317 questionnaires from students in Grades 3–8 at baseline; the average ages [standard deviation (SD)] were 12.5 (1.9; Baseline characteristics of students in the two groupsFor the final evaluation survey, the study obtained a total of 9757 responses from students in Grades 3–9 (control group: 3663; intervention group: 6094). The average ages (SD) of intervention and control groups were 12.2 (1.9) and 12.2 (2.0) years, respectively. The study observed no difference in the basic demographic characteristics between the two groups (