Table 2

Percentage (and number), crude and adjusted odds ratio (OR), and 98% confidence intervals (CI) of students daily smoking and heavy smoking in relation to perceived exposure to teachers smoking outdoors on school grounds and inside school building, sex, perceived exposure to students smoking outdoors on school premises, proportion of smokers in the class, parental smoking, and best friends smoking behaviour

Variable	Daily smokers (% (No.))	Crude OR† (98% CI)	Adjusted OR† (98% CI)	Heavy smokers (% (No.))	Crude OR‡ (98% CI)	Adjusted OR‡ (98% CI)
*Reference category.
†Dependent variable: daily smoking versus no smoking daily
‡Dependent variable: smoking >20 cigarettes a week versus smoking <21 cigarettes a week.
Exposed to teachers smoking outdoors
No	12% (61)	1*	1*	10% (50)	1*	1*
Yes	22% (173)	2.1 (1.4 to 3.0)	1.8 (1.2 to 2.8)	19% (155)	2.3 (1.5 to 3.4)	2.0 (1.2 to 3.1)

Exposed to teachers smoking inside school building
No	17% (29)	1*	1*	14% (24)	1*	1*
Yes	18% (205)	1.1 (0.6 to 1.8 )	0.9 (0.5 to 1.6)	16% (181)	1.1 (0.7 to 2.0)	0.9 (0.5 to 1.7)

Sex
Boy	14% (89)	1*	1*	12% (78)	1*	1*
Girl	21% (145)	1.6 (1.1 to 2.3)	1.3 (0.9 to 1.9)	18% (127)	1.6 (1.1 to 2.3)	1.3 (0.9 to 2.0)

Exposed to pupils smoking outdoors
No	6% (6)	1*	1*	5% (5)	1*	1*
Yes	19% (228)	3.7 (1.4 to 9.9)	1.5 (0.5 to 4.4)	16% (200)	3.9 (1.3 to 11.5)	1.6 (0.5 to 5.0 )

Proportion of smokers in the class
<20% smokers	9% (66)	1*	1*	8% (58)	1*	1*
>20% smokers	30% (168)	4.4 (3.1 to 6.4)	3.7 (2.5 to 5.5)	26% (147)	4.2 (2.9 to 6.3)	3.3 (2.2 to 5.1)

Parents’ smoking behaviour Father
Non-smoker	11% (77)	1*	1*	11% (77)	1*	1*
Smoker	25% (157)	2.6 (1.8 to 3.8)	1.9 (1.3 to 3.0)	20% (128)	2.0 (1.4 to 2.9 )	1.4 (0.9 to 2.2)

Mother
Non-smoker	12% (96)	1*	1*	11% (89)	1*	1*
Smoker	26% (138)	2.6 (1.8 to 3.6)	1.7 (1.1 to 2.6)	22% (116)	2.2 (1.6 to 3.2 )	1.6 (1.0 to 2.4 )

Best friends’ smoking behaviour
Non-smoker	4% (29)	1*	1*	3% (24)	1*	1*
Smoker	34% (205)	11.9 (7.3 to 19.3)	9.1 (5.5 to 15.1)	30%(181)	12.2 (7.2 to 20.6)	9.2 (5.4 to 15.7 )