Demographic characteristics of the study population
| Variables | Overall (N=27 009) | Normal weight (N=19 776) | Overweight/obesity (N=7233) | P value |
| Age (years) | 0.067 | |||
| 7–12 | 7773 (28.8) | 5650 (28.6) | 2123 (29.4) | |
| 13–15 | 9185 (34.0) | 6805 (34.4) | 2380 (32.9) | |
| 16–18 | 10 051 (37.2) | 7321 (37.0) | 2730 (37.7) | |
| Gender | <0.001 | |||
| Boy | 18 191 (67.4) | 13 917 (70.4) | 4274 (59.1) | |
| Girl | 8818 (32.6) | 5959 (29.6) | 2959 (40.9) | |
| Residence region | <0.001 | |||
| Urban | 19 069 (70.6) | 13 406 (67.8) | 5663 (78.3) | |
| Rural | 7940 (29.4) | 6370 (32.2) | 1570 (21.7) | |
| Educational stages | <0.001 | |||
| Primary school | 7391 (27.4) | 5367 (27.1) | 2024 (28.0) | |
| Middle school | 9349 (34.6) | 7074 (35.8) | 2275 (31.4) | |
| High school | 10 269 (38.0) | 7335 (37.1) | 2934 (40.6) | |
| BMI (kg/m2) | 25.17±2.99 | 21.07±2.87 | 26.45±3.27 | <0.001 |
| Birth weight | ||||
| Low | 3522 (13.0) | 2306 (11.7) | 1216 (16.8) | |
| Normal | 14 172 (52.5) | 10 699 (54.1) | 3473 (48.0) | |
| High | 9315 (34.5) | 6771 (34.2) | 2544 (35.2) | |
| Delivery mode | <0.001 | |||
| Natural delivery | 15 275 (56.6) | 11 524 (58.3) | 3751 (51.9) | |
| Caesarean section | 11 734 (43.4) | 8252 (41.7) | 3482 (48.1) | |
| Paternal age | 41.20±2.02 | 41.21±2.03 | 41.18±1.99 | 0.326 |
| Paternal BMI | <0.001 | |||
| Normal | 15 659 (58.0) | 11 595 (58.6) | 4064 (56.2) | |
| Overweight | 7327 (27.1) | 5364 (27.1) | 1963 (27.1) | |
| Obesity | 4023 (14.9) | 2817 (14.3) | 1206 (16.7) | |
| Paternal education level | <0.001 | |||
| Middle school or below | 6969 (25.8) | 5636 (28.5) | 1333 (18.4) | |
| High school | 8137 (30.1) | 5736 (29.0) | 2401 (33.2) | |
| University or above | 11 903 (44.1) | 8404 (42.5) | 3499 (48.4) | |
| Maternal age | 40.12±3.06 | 40.18±2.01 | 40.22±2.97 | <0.001 |
| Maternal BMI | <0.001 | |||
| Normal | 12 795 (47.4) | 9837 (49.7) | 2958 (40.9) | |
| Overweight | 8506 (31.5) | 6151 (31.1) | 2355 (32.6) | |
| Obesity | 5708 (21.1) | 3788 (19.2) | 1920 (26.5) | |
| Maternal education level | <0.001 | |||
| Middle school or below | 7092 (26.3) | 5616 (28.4) | 1476 (20.4) | |
| High school | 8671 (32.1) | 6351 (32.1) | 2320 (32.1) | |
| University or above | 11 246 (41.6) | 7809 (39.5) | 3437 (47.5) | |
| Sleep duration | <0.001 | |||
| Very short | 8637 (32.0) | 5929 (30.0) | 2708 (37.4) | |
| Short | 8283 (30.7) | 6099 (30.8) | 2184 (30.2) | |
| Recommended | 7111 (26.3) | 5612 (28.4) | 1499 (20.7) | |
| Long | 2978 (11.0) | 2136 (10.8) | 842 (11.7) | |
| Physical activity time | <0.001 | |||
| ≤2 hours/day | 23 264 (87.5) | 17 436 (88.2) | 6188 (85.6) | |
| ＞2 hours/day | 3385 (12.5) | 2340 (11.8) | 1045 (14.4) | |
| Screen time | <0.001 | |||
| ≤2 hours/day | 19 720 (73.0) | 14 219 (71.9) | 5501 (76.1) | |
| ＞2 hours/day | 7289 (27.0) | 5557 (28.1) | 1732 (23.9) |
BMI, body mass index.