Table 1 Descriptive statistics for variables at the child level (level-1)

Height (cm)

143.46 ± 6.42

143.49 ± 7.06

0.060

0.952

Weight (kg)

40.52 ± 9.23

40.28 ± 9.23

-0.332

0.740

BMI (kg/m²)

19.54 ± 3.45

19.41 ± 3.36

-0.511

0.610

Number of siblings

0.97 ± 0.80

0.95 ± 0.83

-0.230

0.818

SED time

449.73 ± 73.07

482.21 ± 66.45

6.085

<0.001

Sleep time (hours/day)

8.14 ± 1.02

8.21 ± 0.96

0.964

0.335

BMI classification (%)

χ ²

p- value

Normal-weight

49.05%

58.0%

4.920

0.026

Overweight

15.1%

17.6%

0.772

0.380

Obese

35.4%

24.4%

9.895

0.002

Annual family income

Category 1

14.1%

22.7%

Category 2

33.2%

29.3%

Category 3

21.2%

16.7%

Category 4

11.6%

9.3%

Category 5

7.1%

7.0%

Category 6

4.6%

6.0%

Category 7

2.9%

3.7%

Category 8

5.4%

5.3%

Computer use on school days

Did not use

36.4%

46.2%

<1 hour

23.3%

29.4%

1 hour

21.0%

16.8%

2 hours

12.8%

5.2%

3 hours

3.3%

1.8%

4 hours

1.6%

0.3%

5 or more hours

1.6%

0.3%