Table 4.

Results of multivariate logistic regression analyses of predictors of initiation by early (grade 7), middle (grade 9), and late (grade 11) adolescence, AdoQuest 2005–2011

Predictor	Early adolescence, n = 1,221, AOR (95% CI)a	Middle adolescence, n = 737, AOR (95% CI)a	Late adolescence, n = 690, AOR (95% CI)a
Sociodemographic factors
Sex
Female	Ref	Ref	Ref
Male	.86 (.60–1.23)	.73 (.49–1.08)	1.02 (.71–1.44)
Ageb	1.04 (1.00–1.08)	1.05 (1.01–1.09)	.98 (.96–1.01)
Maternal education
No university	Ref	Ref	Ref
University	.61 (.37–1.03)	.65 (.48–.88)	.65 (.44–.96)
Indicators of smoking in the social environment
Father smokes
No	Ref	Ref	Ref
Yes	2.09 (1.38–3.15)	2.00 (1.49–2.75)	1.67 (1.22–2.29)
Mother smokes
No	Ref	Ref	Ref
Yes	2.72 (1.96–3.77)	2.27 (1.56–3.31)	1.64 (.98–2.75)
Sibling(s) smoke
No	Ref	(not measured)	Ref
Yes	2.22 (1.36–3.61)		2.62 (1.64–4.19)
Friends smoke
No	Ref	(not measured)	Ref
Yes	5.78 (3.90–8.58)		1.83 (1.31–2.57)
Home smoking rules
Full ban	Ref	Ref	Ref
Partial ban	1.51 (.90–2.52)	1.39 (.99–1.94)	1.37 (.84–2.24)
No ban	3.37 (2.05–5.52)	2.35 (1.44–3.86)	1.27 (.69–2.31)
Number of smokers in homec	1.75 (1.38–2.23)	1.76 (1.37–2.26)	1.39 (1.08–1.78)
Number of days in past week exposed to smoking in carsc	1.68 (1.39–2.04)	1.60 (1.30–1.97)	1.52 (1.15–1.99)
School smoking rules
Banned	Ref	Ref	Ref
Allowed	.97 (.58–1.61)	1.96 (1.25–3.10)	1.45 (.96–2.18)
Do not know	.73 (.76–1.37)	.87 (.55–1.37)	.23 (.07–.81)
Psychosocial characteristics
Depressive symptomsb	1.60 (1.26–2.02)	1.92 (1.45–2.54)	.76 (.58–1.00)
School connectednessb	.59 (.45–.78)	.64 (.48–.86)	.93 (.66–1.31)
Lifestyle indicators
Hours of TV per weekc	1.09 (.86–1.39)	(not measured)	.90 (.63–1.28)
Use other tobacco products
No	Ref	Ref	Ref
Yes	3.61 (1.37–9.49)	3.00 (1.47–6.09)	3.56 (2.24–5.67)
Weight-related goals
No change	Ref	(not measured)	Ref
Lose	1.20 (.85–1.70)		1.19 (.81–1.77)
Gain	1.32 (.40–4.35)		1.43 (.62–3.30)
Perceived need for cigarettes
Really need a cigarette
No	No	(not measured)	Ref
Yes	5.66 (2.65–12.11)		5.03 (1.35–18.77)
Have strong cravings
No	Ref	Ref	Ref
Yes	4.54 (2.12–9.76)	2.99 (.99–9.04)	5.56 (1.23–25.15)

ORs and 95% CIs in bold are statistically significant at p < 0.05.

AOR = adjusted odds ratio; CI = confidence interval.

^aAll multivariate analyses performed after imputing missing values. All models were adjusted for sex, age, and mother’s education.

^bEntered as a continuous variable.

^cEntered as an ordinal variable.