Table 5 Subgroup and Meta-regression analyses of included studies

Geographic location

0.786

Asia

5

26

0.110

0.505

America

6

35

0.154

0.606

Europe

6

25

0.132

0.426

Study setting

0.858

Not school

5

27

0.089

0.589

School

13

30

0.207

0.411

Study design

0.008*

Cohort studies

2

51

0.374

0.648

Cross-sectional

16

27

0.178

0.383

Method of assessment

0.048*

Face-to-face interview

2

49

0.306

0.669

Self-reported

16

27

0.179

0.387

Instruments

0.280

Self-designed

3

17

0.052

0.445

Others (standardized)

15

32

0.208

0.458

Continuous variable

n

Coefficient

95% CI Lower

95% CI Upper

p-value

Sample size

18

-0.00

-0.000

0.000

0.333

Age

6

0.03

-0.829

0.898

0.937