Variables

Regression coefficient

β

P

95% CI

Constant

4.49

3.91

to

5.08

4.49

<0.001

Grade

−0.03

−0.05

to

0.00

−0.04

0.071

Gender (male: 1; female: 2)

0.24

0.15

to

0.33

0.09

<0.001

School day sleep duration

−0.44

−0.49

to

−0.39

−0.42

<0.001

Standardized BMI

−0.06

−0.10

to

−0.01

−0.04

0.011

Self-reported academic performance

0.02

−0.04

to

0.07

0.01

0.543

Sleepiness during class

0.02

−0.04

to

0.08

0.01

0.522

Breakfast taking

0.01

−0.07

to

0.09

0.01

0.768

Defecation frequency

−0.03

−0.08

to

0.02

−0.02

0.233

After-school activity (hrs./week)

−0.02

−0.02

to

−0.01

−0.10

<0.001

Physical activity (days/week)

−0.07

−0.09

to

−0.06

−0.16

<0.001

Average screen time a day (hrs)

0.05

0.00

to

0.11

0.03

0.070