Table 1.
Descriptive characteristics of participants.
| Full sample (n = 6,932) | Boys (n = 2,997) | Girls (n = 3,935) | |
|---|---|---|---|
| Age (years) | |||
| Mean (SD) | 15.2 (1.8) | 15.2 (1.6) | 15.2 (1.9) |
| Ethnic background | |||
| White | 50.9 | 49.9 | 52.0 |
| Black | 9.4 | 9.3 | 9.5 |
| East/South-East Asian | 14.0 | 15.3 | 12.6 |
| South Asian | 9.0 | 9.2 | 8.7 |
| Other | 16.7 | 16.3 | 17.1 |
| Subjective socioeconomic status | |||
| Mean (SD) | 6.9 (1.7) | 7.0 (1.6) | 6.9 (1.8) |
| Body mass index z-score | |||
| Mean (SD) | 0.3 (1.1) | 0.4 (1.0) | 0.3 (1.3) |
| Physical activity*** | |||
| Not meeting | 80.2 | 74.7 | 85.9 |
| Meeting | 19.8 | 25.3 | 14.1 |
| Screen time | |||
| Not meeting | 75.7 | 75.0 | 76.5 |
| Meeting | 24.3 | 25.0 | 23.5 |
| Sleep duration*** | |||
| Not meeting | 65.8 | 61.4 | 70.4 |
| Meeting | 34.2 | 38.6 | 29.6 |
| Combinations of movement recommendations*** | |||
| Meeting none | 44.5 | 39.3 | 49.8 |
| Physical activity only | 8.0 | 9.3 | 6.5 |
| Screen time only | 9.8 | 8.0 | 11.6 |
| Sleep duration only | 18.5 | 19.8 | 17.1 |
| Physical activity and screen time only | 3.6 | 4.7 | 2.5 |
| Physical activity and sleep only | 4.7 | 6.4 | 3.0 |
| Screen time and sleep duration only | 7.4 | 7.5 | 7.4 |
| Meeting all 3 recommendations | 3.5 | 4.8 | 2.1 |
| Life stress*** | |||
| Not at all | 14.3 | 19.9 | 8.5 |
| A little | 27.1 | 31.4 | 22.8 |
| Some | 25.3 | 24.8 | 25.9 |
| A lot | 22.1 | 16.4 | 27.9 |
| Almost more than I could take | 11.2 | 7.4 | 15.0 |
| Self-esteem (satisfied with myself)*** | |||
| Strongly agree | 29.1 | 37.8 | 20.1 |
| Somewhat agree | 43.6 | 43.0 | 44.3 |
| Somewhat disagree | 18.0 | 13.5 | 22.6 |
| Strongly disagree | 9.3 | 5.7 | 12.9 |
Data are shown as column %, unless otherwise indicated. SD, standard deviation.
***
p of differences between boys and girls <0.001.