Table 1.
Sample Characteristics
| Variables | Total sample (n = 1629) n (%)/mean (SD, range) |
|---|---|
| Grade (n = 1629)a | |
| 7 | 389 (23.9) |
| 8 | 444 (27.3) |
| 9 | 368 (22.6) |
| 10 | 302 (18.5) |
| 12 | 126 (7.7) |
| School bandb (n = 1629) | |
| 1 | 688 (42.2) |
| 2 | 465 (28.5) |
| 3 | 476 (29.2) |
| Female gender (n = 1619) | 816 (50.4) |
| Age, yr (n = 1590) | 14.8 (1.7, 12-19) |
| 12-13 | 380 (23.9) |
| 14 | 371 (23.3) |
| 15 | 307 (19.3) |
| 16 | 277 (17.0) |
| 17-19 | 255 (16.1) |
| Parents martial status (n = 1589) | |
| Married/cohabiting | 1478 (93.0) |
| Divorced/widowed | 111 (7.0) |
| Father's occupation (n = 1538) | |
| Managers, administrators, and professionals | 159 (10.3) |
| Associate professionals | 199 (12.9) |
| Clerks, service workers, skilled and semi-skilled manual workers | 600 (39.0) |
| Unskilled manual workers | 347 (22.6) |
| Retired | 91 (5.9) |
| Unemployed/homemakers | 142 (9.2) |
| Body mass index, kg/m2 (n = 1502) | 19.0 (3.3, 9.9-42.2) |
| Overweightc (n = 1502) | 120 (8.0) |
| Had smoking habit (n = 1617) | 50 (3.1) |
| Alcohol used (n = 1610) | 26 (1.6) |
| Coffee used (n = 1616) | 102 (6.3) |
| Exercise ≥3 times/weeke (n = 1616) | 488 (30.2) |
| Part-time work ≥5 hr/week (n = 1608) | 95 (5.9) |
| Self-reported academic performancef (n = 1377) | |
| Excellent | 449 (32.6) |
| Good | 694 (50.4) |
| Marginal | 234 (17.0) |
a
Difference from total n reflects omissions on reporting forms. bLower band indicates higher school academic ranking. cInternational Task Force on Obesity overweight reference, sex-age-specific BMI cut-offs that correspond to BMI = 25 at age 18 yr. dOften or almost always. e Each time ≥30 min. f Based on ranking in class, average mark or overall grade.