Table 3.

Proportion of participants who initiated smoking by early (seventh grade), middle (ninth grade), and late (11th grade) adolescence according to categories of exposures, AdoQuest 2005–2011

	Early adolescence, n = 1,221		Middle adolescence, n = 737		Late adolescence, n = 690
	Total n^a	% Initiated	Total n^a	% Initiated	Total n^a	% Initiated
Sociodemographic factors
Sex
Female	695	11.4	418	30.9	368	22.8
Male	526	10.3	319	24.5	322	22.7
Age, months
1st tertile	90	7.7	221	25.3	214	28.5
2nd tertile	410	11.7	253	25.3	263	20.5
3rd tertile	396	11.9	249	32.9	201	19.4
Maternal education
No university	679	12.1	452	31.4	406	26.1
University	299	7.0	254	21.3	249	18.1
Indicators of smoking in the social environment
Father smokes^b
No	896	8.9	551	24.5	527	20.9
Yes	288	17.4	142	40.8	122	30.3
Mother smokes^b
No	946	8.5	582	24.9	544	21.3
Yes	246	20.7	116	43.1	106	30.2
Siblings smoke
No	1,122	10.2	(not measured)		598	20.4
Yes	83	20.5			81	39.5
Friends smoke
No	1,084	8.2	(not measured)		491	19.6
Yes	119	35.3			199	30.7
Home smoking rules
Full ban	518	7.3	413	23.7	446	21.1
Partial ban	423	10.2	231	30.7	182	26.4
No ban	194	21.6	77	42.9	58	24.1
Number of smokers in the home
0	796	7.3	564	24.1	558	21.9
1	234	16.2	102	33.3	82	19.5
≥ 2	168	19.6	64	53.1	46	41.3
Number of days in the past week exposed to smoking in cars
0	914	8.1	607	25.9	548	20.4
1–2	142	13.4	84	28.6	91	28.6
3–4	59	25.4	27	55.6	34	41.2
5–7	72	29.2	15	66.7	11	36.4
School smoking rules
Ban	789	10.3	506	25.3	464	21.6
No ban	134	10.4	139	38.8	191	28.8
Do not know	243	14.4	82	23.2	30	6.7
Psychological characteristics
Depressive symptoms
1st tertile	439	8.2	243	19.8	243	26.7
2nd tertile	319	9.7	199	23.6	170	21.2
3rd tertile	422	14.5	275	38.5	259	19.7
School connectedness^c
1st	246	16.3	274	34.7	130	23.1
2nd	328	10.4	168	22.6	238	22.3
3rd	324	7.4	263	23.6	308	22.4
4th	268	10.8
Lifestyle indicators
Hours of TV per day
<1	193	8.3	(not measured)		465	22.8
1–2	532	11.5			181	24.3
3–4	346	10.7			35	14.3
≥5	119	11.8			2	0.0
Use other tobacco products
No	1,080	10.5	702	26.6	627	20.3
Yes	22	36.4	32	53.1	63	47.6
Weight-related goals
No change	647	10.2	(not measured)		422	21.8
Lose	369	11.7			193	24.9
Gain	47	10.6			51	29.4
Perceived need for cigarettes
Really need a cigarette
No	1,099	10.0	(not measured)		669	22.1
Yes	23	43.5			12	58.3
Have strong cravings
No	1,024	9.5	708	27.5	675	22.2
Yes	37	37.8	9	55.6	7	71.4

Denominators differ because of missing data.

Measured in fifth and ninth grades.

School connectedness reported in quartiles in fifth grade and tertiles in seventh and ninth grades.