Table 1 Demographic and lifestyle characteristics of adolescents

N

2054

1013

1041

Physical characteristics

Age, yr

14.8 ± 1.3

14.8 ± 1.3

14.8 ± 1.3

0.208

Weight, kg

58.4 ± 11.0

62.5 ± 11.9

54.3 ± 8.4

<0.001

Height, cm

166.5 ± 9.2

170.5 ± 9.6

162.7 ± 6.9

<0.001

Body mass index, kg/m²

21.0 ± 2.9

21.4 ± 3.2

20.5 ± 2.6

<0.001

Body mass index, Z-score

−0.12 ± 1.00

−0.06 ± 1.00

−0.18 ± 0.99

<0.010

Infection and allergy frequency

Infection incidence in the last 3 mo., %

32

28

36

<0.001

Allergy incidence in the last 3 mo., %

36

28

44

<0.001

Health behaviours

Overweight + obesity, %

17.5

24.8

10.5

<0.001

Physical activity ≥5 d/week, %

17

22

12

<0.001

TV viewing <2 hr/d, %

70

71

68

0.160

Sleep duration ≥8 hr/d, %

67

68

65

0.174

Fruit consumption ≥2 servings/d, %

22

20

24

0.033

Use of screen devices at leisure time <60 min/d, %

79

68

89

<0.001

Homework ≥60 min/d, %

64

55

72

<0.001