Table 2.
Baseline characteristics according to sleep duration among normal weight children aged 6–17 years
| Characteristic | > 9 h | 7–9 h | < 7 h | P for difference |
|---|---|---|---|---|
| Age group | ||||
| Before adolescents (male: 6–11 years, female:6–10 years) | 2947 | 4293 | 551 | < 0.001 |
| Young adolescents (male: 12–15 years, Female: 11–14 years) | 643 | 3044 | 823 | |
| Elder adolescents (male: 15–17 years, Female: 16–17 years) | 76 | 1285 | 1382 | |
| Demographics | ||||
| No. of participants | 3666 | 8622 | 2756 | |
| Male (%) | 48.0 | 46.4 | 42.2 | < 0.001 |
| Age (years) | 9.64(0.06) | 11.37(0.04) | 13.53(0.07) | < 0.001 |
| From Northern area (%) | 36.8 | 37.2 | 39.7 | < 0.001 |
| Monthly income of Family (%) | < 0.001 | |||
| ≤ 5000 yuan | 24.0 | 60.1 | 15.9 | |
| > 5000 yuan | 26.7 | 58.9 | 14.5 | |
| Not willing to answer | 23.9 | 55.0 | 21.0 | |
| Mother’s education year (%) | < 0.001 | |||
| ≤ 9 | 24.4 | 59.1 | 16.5 | |
| 10–12 | 25.5 | 59.5 | 15.0 | |
| 13–16 | 27.6 | 58.9 | 13.4 | |
| ≥ 16 | 29.2 | 56.1 | 14.7 | |
| Puberty on-set (%) | 8.0 | 27.5 | 59.0 | < 0.001 |
| Lifestyle | ||||
| Physical activity(PA) | ||||
| High-level PA (hour/day) | 0.56(0.14) | 0.52(0.01) | 0.52(0.02) | < 0.001 |
| Middle-level PA (hour/day) | 0.56(0.02) | 0.47(0.01) | 0.46(0.02) | < 0.001 |
| Walking (hour/day) | 0.80(0.02) | 0.76(0.02) | 0.83(0.03) | < 0.001 |
| Sedentary (hour/week) | 34.70(0.52) | 40.03(0.33) | 45.42(0.62) | < 0.001 |
| Dietary intake(serve/day) | ||||
| Meat | 1.14(0.02) | 1.17(0.02) | 1.25(0.03) | < 0.001 |
| Sugar beverage | 0.29(0.02) | 0.41(0.01) | 0.56(0.02) | < 0.001 |
| Fruit | 1.43(0.02) | 1.26(0.01) | 1.21(0.03) | < 0.001 |
| Vegetable | 1.94(0.03) | 1.79(0.02) | 1.71(0.03) | < 0.001 |
| Anthropometry | ||||
| Height (cm) | 139.77(0.31) | 148.07(0.20) | 156.82(0.363) | < 0.001 |
| Weight (kg) | 33.22(0.24) | 39.93(0.15) | 47.43(0.28) | < 0.001 |
| BMI | 16.65(0.05) | 17.70(0.03) | 18.86(0.05) | < 0.001 |
Continuous variables are displayed as mean (standard error), categorical variables are displayed as proportion
P values are from T-tests (continuous variables) and chi-square tests (categorical variables) between boys and girls
BMI body mass index, PA physical activity, HLPA high level physical activity, MLPA middle level activity