Table 4. Associations between each factor and feeling happy/unhappy at senior high school.
| Feeling happy/unhappy at school | ||||||
| Happy at school | Neither/nor | Unhappy at school | ||||
| N | % | % | % | |||
| Total | 59,341 | 62.3 | 29.0 | 8.7 | ||
| Boys | * Intending to study at university | Yes | 17,173 | 63.5 | 28.7 | 7.8 |
| No | 9,125 | 58.9 | 31.1 | 10.0 | ||
| Not yet decided | 2,656 | 43.2 | 38.9 | 17.9 | ||
| * Participating in extracurricular activities | Yes | 19,157 | 65.7 | 27.2 | 7.1 | |
| No | 9,775 | 49.3 | 36.7 | 14.0 | ||
| * Having breakfast | Everyday | 23,362 | 63.1 | 29.0 | 7.9 | |
| Sometimes | 3,102 | 50.6 | 37.2 | 12.2 | ||
| Seldom | 2,545 | 45.1 | 35.3 | 19.6 | ||
| * Bedtimes | Before or at midnight | 13,073 | 64.2 | 28.4 | 7.4 | |
| After midnight | 15,861 | 56.9 | 32.0 | 11.1 | ||
| * Smoking (past 30 days) | No | 26,940 | 61.2 | 30.1 | 8.6 | |
| Yes | 2,039 | 46.4 | 34.0 | 19.6 | ||
| * Drinking (past 30 days) | No | 23,711 | 61.2 | 30.4 | 8.4 | |
| Yes | 5,153 | 55.3 | 30.5 | 14.2 | ||
| * Mental health status | Good | 16,412 | 69.7 | 25.9 | 4.3 | |
| Poor | 12,523 | 47.4 | 36.3 | 16.0 | ||
| Girls | * Intending to study at university | Yes | 16,607 | 69.8 | 24.5 | 5.8 |
| No | 11,167 | 60.6 | 30.2 | 9.2 | ||
| Not yet decided | 2,499 | 45.3 | 36.7 | 18.0 | ||
| * Participating in extracurricular activities | Yes | 18,614 | 69.9 | 24.6 | 5.5 | |
| No | 11,580 | 55.4 | 32.5 | 12.2 | ||
| * Having breakfast | Everyday | 25,821 | 66.8 | 26.5 | 6.8 | |
| Sometimes | 2,920 | 52.2 | 34.7 | 13.2 | ||
| Seldom | 1,580 | 47.8 | 32.7 | 19.6 | ||
| * Bedtimes | Before or at midnight | 12,305 | 67.3 | 26.3 | 6.4 | |
| After midnight | 17,950 | 62.3 | 28.5 | 9.2 | ||
| * Smoking (past 30 days) | No | 29,248 | 65.3 | 27.3 | 7.4 | |
| Yes | 1,042 | 38.3 | 35.6 | 26.1 | ||
| * Drinking (past 30 days) | No | 24,895 | 66.1 | 26.8 | 7.0 | |
| Yes | 5,282 | 56.1 | 31.1 | 12.8 | ||
| * Mental health status | Good | 12,465 | 77.9 | 19.7 | 2.3 | |
| Poor | 17,803 | 54.9 | 33.1 | 12.0 | ||
Subjects for whom data were missing were excluded from the analysis.
*P value was calculated by χ2-test, each factors(Intending to study at university, Participating in extracurricular activities, Having breakfast, Bedtimes, breakfast, Bedtimes, Smoking, Drinking, Mental health status), P<0.01.