| |
Subjective SES (%)
|
Chi-square
|
Trend
|
|---|
| |
High
|
Middle
|
Low
|
p
|
p
|
|---|
|
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*
|
|
Physical activity
|
|
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
|
- Chi-square and trend test
- SES socioeconomic status
- *p < 0.05. The numbers in Italics showed a statistical significant
