Table 3 Knowledge, attitudes, and perceptions of parental, sibling, and peer behavior on smoking and drinking (n = 358)

Intention of smoking and drinking (those who answered "Yes")

 Will smoke tobacco after 18 years or older

24

(11.1)

8

(5.8)

32

(9.0)

0.09

 Will drink alcohol after 18 years or older

30

(14.0)

13

(9.5)

43

(12.3)

0.21

Knowledge on smoking and drinking (those who answered "I think so")

 Smoking is bad for health

187

(86.6)

97

(70.3)

284

(80.2)

 < 0.001

 It is difficult to quit smoking

190

(88.8)

89

(64.5)

279

(79.3)

 < 0.001

 Secondhand smoking is bad for health

196

(91.2)

101

(72.7)

297

(83.9)

 < 0.001

 Drinking too much alcohol is bad for health

195

(90.7)

100

(71.9)

295

(83.3)

 < 0.001

Attitude toward smoking and drinking (those who answered "I think so")

 Young smokers have more friends

170

(78.7)

75

(54.7)

245

(69.4)

 < 0.001

 Tobacco makes us study effectively

37

(17.2)

26

(19.0)

63

(17.9)

0.67

 Young drinkers have more friends

171

(79.2)

89

(64.5)

260

(73.4)

 < 0.001

 Alcohol makes us sleep well

73

(34.1)

46

(33.1)

119

(33.7)

0.84

Self-efficacy to refuse tobacco/alcohol (Mean ± SD)

 Self-efficacy score to refuse tobacco (1–4)

3.76 ± 0.64

3.59 ± 0.60

3.69 ± 0.65

 < 0.001

 Self-efficacy score to refuse alcohol (1–4)

3.73 ± 0.63

3.59 ± 0.74

3.68 ± 0.68

0.03

Parental involvement (those who answered "Yes")

 Understanding problems and worries

88

(77.2)

63

(84.0)

151

(79.9)

0.25

 Giving advice and guidance

106

(93.0)

68

(90.7)

174

(92.1)

0.56

 Having open communication

105

(91.3)

65

(85.5)

170

(89.0)

0.21

Parental smoking and drinking (those who answered "Yes")

 Father/male guardian smokes tobacco

50

(23.4)

46

(34.8)

96

(27.7)

0.02

 Mother/female guardian smokes tobacco

16

(7.4)

6

(4.4)

22

(6.2)

0.25

 Father/male guardian drinks alcohol

95

(44.0)

55

(41.0)

150

(42.9)

0.59

 Mother/female guardian drinks alcohol

47

(22.0)

16

(11.7)

63

(17.9)

0.01

Parental health guidance on substance use (those who answered "Yes")

 Talking about negative effect of smoking

145

(66.8)

44

(31.7)

189

(53.1)

 < 0.001

 Talking about negative effect of drinking

127

(58.5)

38

(27.3)

165

(46.3)

 < 0.001

 Talking about negative effect of marijuana use

119

(54.8)

31

(22.5)

150

(42.3)

 < 0.001

Parental request to buy tobacco/alcohol (those who answered "Yes")

 Ever bought tobacco at the request of parents/guardians

67

(30.9)

49

(35.0)

116

(32.5)

0.42

 Ever bought alcoholic drinks at the request of parents/guardians

20

(9.2)

21

(15.0)

41

(11.5)

0.09

Parental offer of tobacco/alcohol (those who answered "Yes")

 Offer of tobacco by parents/guardians

3

(1.4)

8

(5.8)

11

(3.1)

0.02

 Offer of alcohol by parents/guardians

3

(1.4)

11

(8.0)

14

(3.9)

 < 0.001

Sibling smoking and drinking (those who answered "Yes")

 Brother or sister smokes tobacco

43

(20.0)

25

(18.2)

68

(19.3)

0.685

 Brother or sister drinks alcohol

50

(23.1)

31

(22.8)

81

(23.0)

0.939

Sibling offer of tobacco/alcohol (those who answered "Yes")

 Offer of tobacco by brother/sister

5

(2.3)

11

(7.9)

16

(4.5)

0.013

 Offer of alcohol by brother/sister

9

(4.1)

14

(10.1)

23

(6.5)

0.025

Peer smoking and drinking (those who answered "Yes")

 Having friends who smoke tobacco

99

(46.5)

46

(37.1)

145

(43.0)

0.09

 Having friends who drink alcohol

84

(39.4)

46

(37.1)

130

(38.6)

0.67

Peer offer of tobacco and alcohol (those who answered "Yes")

 Offer of tobacco by closest friends

19

(8.8)

14

(10.1)

33

(9.3)

0.66

 Offer of alcohol by closest friends

12

(5.5)

14

(10.2)

26

(7.3)

0.10