Table 4 Subjective SES and lifestyles n = 1663

Wakeup time on week day ≥ 7:00 a.m.

3.9

3.6

4.4

0.55

0.59

Skipping breakfast (yes)

5.0

6.8

8.1

0.18

0.07

Screen time on week day (≥ 2 h)

34.2

40.1

41.9

0.04*

0.02*

 Very often

28.1

28.0

29.9

0.82

0.86

 Often

46.0

43.6

43.4

 Rarely

25.9

28.4

26.7

Late bedtime on week day (≥ 10 for junior, and ≥ 10:30 for senior grades children)

10.9

13.4

15.7

0.11

0.04*

Daytime sleepiness (yes)

12.6

17.3

20.8

< 0.01*

< 0.01*

Obesity (yes)

7.2

8.4

8.1

0.74

0.61

Cram school (yes)

29.0

24.2

22.1

0.05

0.02*

Study duration at home (< 1 h)

61.0

61.1

66.9

0.10

0.08

Paternal smoke (yes)

42.0

45.6

43.9

0.47

0.56

Maternal smoke (yes)

8.5

11.7

12.3

0.14

0.07