Table 2 Socio-demographic characteristics of substance users and non-users among Korean adolescents

Age (years), mean (95 % CI)

15.90 (15.70–16.10)

15.00 (14.96–15.04)

1.37 (1.27–1.48)

<0.001

Sex, male, %

65.1

52.1

1.71 (1.33–2.21)

<0.001

Area of residence, %

 Rural

8.2

6.5

ref

 Small city

46.0

49.9

0.83 (0.53–1.32)

0.441

 Large city

45.8

43.6

0.73 (0.46–1.16)

0.184

Paternal Education, %

 Middle school education or lower

11.0

3.4

ref

 High school education

32.4

36.5

0.28 (0.17–0.46)

<0.001

 College degree or higher

56.6

60.0

0.3 (0.19–0.47)

<0.001

Maternal Education, %

 Middle school education or lower

12.8

3.0

ref

 High school education

35.1

46.9

0.17 (0.1–0.29)

<0.001

 College degree or higher

52.1

50.2

0.24 (0.15–0.39)

<0.001

Residential type, %

 With family

59.5

96.1

ref

 With relatives

9.0

0.8

18.03 (12.38–26.25)

<0.001

 With friends, alone, domitory

11.2

2.7

6.7 (4.61–9.73)

<0.001

 Facility

20.3

0.4

88.78 (63.81–123.54)

<0.001

Socio-economic status, %

 Low

25.0

3.7

ref

 Low-Middle

16.4

14.2

0.17 (0.12–0.24)

<0.001

 Middle

19.9

48.4

0.06 (0.04–0.09)

<0.001

 High-Middle

16.4

25.7

0.1 (0.06–0.15)

<0.001

 High

22.3

7.9

0.42 (0.31–0.57)

<0.001

Academic achievement, %

 Low

29.9

10.8

ref

 Low-Middle

18.9

24.1

0.29 (0.2–0.4)

<0.001

 Middle

18.4

28.0

0.24 (0.17–0.33)

<0.001

 High-Middle

10.2

24.9

0.15 (0.1–0.23)

<0.001

 High

22.6

12.2

0.67 (0.5–0.9)

0.008

Alcohol use

85.1

42.8

7.64 (5.5–10.62)

<0.001

Tobacco use

78.6

19.7

15.01 (11.41–19.75)

<0.001