Table 1.
Summary of study sample characteristics
| Variable | Boys | Girls | |||||
|---|---|---|---|---|---|---|---|
| N | Mean or proportion | SD | N | Mean or proportion | SD | ||
| Age (years) | 5,278 | 12.9 | 3.5 | 5,672 | 13.2 | 3.5 | |
| Height (cm) | 5,276 | 157.4 | 19.6 | 5,672 | 153.2 | 15.0 | |
| Weight (kg) | 5,274 | 49.8 | 18.4 | 5,669 | 46.4 | 14.6 | |
| BMI (kg/m2) | 5,273 | 19.3 | 3.7 | 5,669 | 19.2 | 3.6 | |
| Waist (cm) | 5,275 | 68.0 | 10.0 | 5,666 | 64.8 | 8.3 | |
| SDS_height | 5,276 | −0.01 | 1.00 | 5,672 | −0.05 | 1.01 | |
| SDS_weight | 5,274 | −0.01 | 1.00 | 5,669 | −0.03 | 1.02 | |
| SDS_BMI | 5,273 | −0.01 | 1.00 | 5,669 | −0.01 | 1.02 | |
| SDS_waist | 5,275 | −0.01 | 1.00 | 5,666 | 0.01 | 1.02 | |
| Overweight (incl. obesity) | 974 | 18.2 | – | 829 | 14.6 | – | |
| Obesity | 230 | 4.1 | – | 171 | 3.0 | – | |
| Maternal education | Primary | 400 | 7.6 | – | 450 | 7.9 | – |
| Vocational | 1,656 | 31.4 | – | 1,921 | 33.9 | – | |
| Secondary | 2,155 | 40.8 | – | 2,234 | 39.4 | – | |
| University | 1,067 | 20.2 | – | 1,067 | 18.8 | – | |
| Paternal education | Primary | 420 | 8.0 | – | 472 | 8.3 | – |
| Vocational | 2,551 | 48.3 | – | 2,878 | 50.7 | – | |
| Secondary | 1,636 | 31.0 | – | 1,616 | 29.3 | – | |
| University | 671 | 12.7 | – | 661 | 11.7 | – | |
| Income per capita | ≤500 PLN | 2,496 | 47.3 | – | 2,768 | 48.8 | – |
| 501–1,000 PLN | 1,719 | 32.6 | – | 1,778 | 31.4 | – | |
| 1,001–1,500 PLN | 598 | 11.3 | – | 654 | 11.5 | – | |
| >1,500 PLN | 465 | 8.8 | – | 472 | 8.3 | – | |
| Number of children | 1 | 620 | 11.8 | – | 687 | 12.1 | – |
| 2 | 2,336 | 44.3 | – | 2,405 | 42.4 | – | |
| 3 | 1,312 | 24.9 | – | 1,422 | 25.1 | – | |
| 4 and more | 1,010 | 19.1 | – | 1,158 | 20.4 | – | |
| Dwellinga | Rural | 1,659 | 40.7 | – | 1,664 | 39.9 | – |
| Urban | 2,422 | 59.3 | – | 2,502 | 60.1 | – | |
SD standard deviation, SDS standard deviation score
aOnly pupils from primary and middle schools