Table 1 Descriptive characteristics of the participating children

Age (years)

9.3 ± 1.7 (9.16–9.45)

9.2 ± 1.7 (9.06–9.35)

9.2 ± 1.7 (9.10–9.30)

0.165

Body weight (kg)

38.6 ± 23.2 (36.6–40.6)

33.2 ± 12.9 (32.9–34.3)

35.8 ± 18.9 (34.7–36.9)

<  0.001

Body height (cm)

133.6 ± 11.7 (132.6–134.6)

133.1 ± 12.5 (132.0–134.2)

133.4 ± 12.1 (132.7–134.1)

0.517

Body mass index (BMI)

20.8 ± 9.6 (20.0–21.6)

18.1 ± 4.4 (17.7–18.5)

19.4 ± 7.6 (18.9–19.9)

<  0.001

Average breakfast intake (day/week)

3.44 ± 2.3 (3.24–3.64)

3.58 ± 2.3 (3.38–3.78)

3.51 ± 2.3 (3.37–3.65)

0.350

 Public school

3.07 ± 2.2 (2.88–3.26)

3.52 ± 2.3 (3.32–3.72)

3.30 ± 2.3 (3.16–3.44)

Gender by school interaction = 0.001

 Private school

4.23 ± 2.3 (4.03–4.43)

3.68 ± 2.3 (3.48–3.87)

3.95 ± 2.3 (3.81–4.09)

Daily breakfast intake (%)

19.3

22.1

20.7

0.285

 Public school

13.3

21.4

17.3

0.005

 Private school

32.5

23.6

27.9

0.070

p-value

<  0.001

0.736

<  0.001