Table 3. Associations between each factor and feeling happy/unhappy at junior high school.
| Feeling happy/unhappy at school | ||||||
| Happy at school | Neither/nor | Unhappy at school | ||||
| N | % | % | % | |||
| Total | 37,991 | 67.2 | 26.1 | 6.6 | ||
| Boys | * Intending to study at university | Yes | 2,888 | 70.3 | 23.0 | 6.7 |
| No | 12,232 | 69.4 | 24.9 | 5.7 | ||
| Not yet decided | 3,565 | 56.7 | 32.9 | 10.4 | ||
| * Participating in extracurricular activities | Yes | 15,498 | 69.6 | 24.7 | 5.7 | |
| No | 3,102 | 55.2 | 32.9 | 11.9 | ||
| * Having breakfast | Everyday | 16,677 | 69.5 | 24.8 | 5.6 | |
| Sometimes | 1,334 | 50.7 | 36.7 | 12.6 | ||
| Seldom | 762 | 42.8 | 36.1 | 21.1 | ||
| * Bedtimes | Before or at midnight | 13,758 | 70.3 | 24.5 | 5.2 | |
| After midnight | 4,901 | 58.5 | 30.4 | 11.1 | ||
| * Smoking (past 30 days) | No | 18,298 | 67.6 | 26.1 | 6.3 | |
| Yes | 457 | 47.7 | 26.3 | 26.0 | ||
| * Drinking (past 30 days) | No | 16,963 | 68.0 | 25.9 | 6.1 | |
| Yes | 1,630 | 59.8 | 27.6 | 13.6 | ||
| * Mental health status | Good | 12,948 | 75.2 | 22.1 | 2.7 | |
| Poor | 5,759 | 49.0 | 35.1 | 15.9 | ||
| Girls | * Intending to study at university | Yes | 2,545 | 72.6 | 22.4 | 5.0 |
| No | 13,778 | 68.3 | 25.7 | 6.0 | ||
| Not yet decided | 2,811 | 58.0 | 31.7 | 10.2 | ||
| * Participating in extracurricular activities | Yes | 14,995 | 65.7 | 27.2 | 7.1 | |
| No | 3,975 | 58.6 | 30.5 | 10.9 | ||
| * Having breakfast | Everyday | 17,214 | 69.4 | 25.0 | 5.6 | |
| Sometimes | 1,377 | 50.5 | 37.5 | 12.0 | ||
| Seldom | 616 | 49.0 | 31.5 | 19.5 | ||
| * Bedtimes | Before or at midnight | 12,526 | 70.5 | 24.7 | 4.8 | |
| After midnight | 6,600 | 61.4 | 28.9 | 9.7 | ||
| * Smoking (past 30 days) | No | 18,917 | 67.8 | 26.0 | 6.2 | |
| Yes | 273 | 39.9 | 36.3 | 23.8 | ||
| * Drinking (past 30 days) | No | 17,251 | 68.6 | 25.5 | 5.9 | |
| Yes | 1,776 | 56.8 | 30.9 | 12.4 | ||
| * Mental health status | Good | 10,452 | 79.6 | 18.8 | 1.6 | |
| Poor | 8,705 | 52.8 | 34.9 | 12.3 | ||
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.