Table 1.
Participants’ sociodemographic characteristics (N = 6894)
| Sociodemographic characteristics | Sample | |
|---|---|---|
| n | % | |
| Gender | ||
| Male | 3248 | 47.1 |
| Female | 3644 | 52.9 |
| Age groups | ||
| 13 years | 1051 | 15.2 |
| 14 years | 1231 | 17.9 |
| 15 years | 1494 | 21.7 |
| 16 years | 1230 | 17.8 |
| 17 years | 924 | 13.4 |
| ≥18 years | 964 | 14 |
| School yeara | ||
| 6th grade (11 years old) | 46 | 0.7 |
| 7th grade (12 years old) | 1517 | 22 |
| 8th grade (13 years old) | 1451 | 21 |
| 9th grade (14 years old) | 1708 | 24.8 |
| 10th grade (15 years old) | 1000 | 14.5 |
| 11th grade (16 years old) | 680 | 9.9 |
| 12th grade (17 years old) | 492 | 7.1 |
| Ever failed a school year | ||
| Yes | 2406 | 34.9 |
| No | 4485 | 65.1 |
aThe ages most commonly associated with each Portuguese school year are presented in parentheses