Table 2.
Baseline characteristics of the analysis sample
| Intervention | Comparison | Total | p a | |
|---|---|---|---|---|
| n = 1322 | n = 1308 | n = 2630 | ||
| Mean age (SD) | 12.1 (0.54) | 12.1 (0.54) | 12.1 (0.54) | 0.784 |
| Female gender (%) | 674 (51.1) | 636 (49.0) | 1310 (50.1) | 0.265 |
| High socioeconomic status (%)b | 472 (43.9) | 510 (45.5) | 982 (44.7) | 0.443 |
| Italian nationality (%) | 1253 (95.0) | 1250 (95.6) | 2503 (95.3) | 0.436 |
| WHO/Europe HBSC Symptom Checklist (SD) | 10.0 (3.56) | 9.9 (3.66) | 9.9 (3.60) | 0.445 |
| Classmate acceptance (SD) | 3.3 (0.85) | 3.3 (0.84) | 3.3 (0.85) | 0.344 |
| Getting along with classmates (SD) | 3.4 (0.76) | 3.5 (0.76) | 3.5 (0.76) | 0.667 |
| Satisfied with teachers (SD) | 3.1 (0.83) | 3.1 (0.83) | 3.1 (0.83) | 0.986 |
| Past 30-day smoking (%) | 30 (2.3) | 63 (4.8) | 93 (3.5) | < 0.001 |
| Past 30-day alcohol intoxication (%) | 33 (2.5) | 37 (2.8) | 70 (2.7) | 0.860 |
| Aggressive behavior (SD) | 18.3 (4.30) | 18.3 (4.41) | 18.3 (4.25) | 0.636 |
aComparison tests between intervention and comparison arms. Chi squared tests for gender, socioeconomic status, nationality, smoking, and alcohol intoxication; t tests for the other variables
bHigh socioeconomic status indicates families in which at least one parent had a university degree or a high-school qualification. Low socioeconomic status indicated families in which at least one parent had a middle-school or elementary qualification