Table 3.

Effects of environmental tobacco smoke exposure (ETS) on subcategories of asthma

		Asthma				Treatments for asthma
		Ever asthma		Active asthma		Medication use		ER visit or hospitalization
		OR	95%CI	OR	95%CI	OR	95%CI	OR	95%CI
ETS
In utero exposure		1.53	(0.95,2.48)	2.06	(1.14,3.70)	1.95	(0.99,3.83)	4.33	(2.03,9.24)
Currently		1.15	(0.92,1.44)	1.39	(1.00,1.93)	1.33	(0.91,1.95)	1.71	(0.98,2.96)
Previous only		0.79	(0.43,1.44)	0.69	(0.28,1.72)	0.56	(0.17,1.79)	NA
ETS sources
Dad		1.07	(0.85,1.35)	1.11	(0.79,1.55)	0.99	(0.67,1.47)	1.28	(0.74,2.20)
Mom		1.40	(0.82,2.39)	1.67	(0.84,3.31)	0.99	(0.39,2.52)	3.16	(1.29,7.77)
Number of smokers
0		1		1		1		1
1		0.91	(0.71,1.19)	1.05	(0.72,1.52)	1.01	(0.66,1.57)	1.04	(0.54,2.01)
2		0.80	(0.53,1.21)	0.92	(0.51,1.67)	0.76	(0.37,1.56)	0.58	(0.17,1.95)
≧ 3		1.61	(1.04,2.50)	2.28	(1.30,4.01)	2.56	(1.40,4.69)	4.56	(2.20,9.46)
p value for trend		0.47		0.05		0.07		0.004
Currently amount of ETS*
0		1		1		1		1
≦ 10		1.06	(0.83,1.36)	1.26	(0.88,1.80)	1.14	(0.75,1.74)	1.21	(0.65,2.26)
> 10		1.42	(0.99,2.03)	2.02	(1.27,3.24)	2.21	(1.32,3.71)	2.81	(1.38,5.73)
p value for trend		0.10		0.005		0.009		0.01
Percent of ETS**
0		1		1		1		1
≦ 20%		0.99	(0.76,1.29)	1.13	(0.77,1.67)	1.19	(0.77,1.85)	1.12	(0.57,2.18)
> 20%		1.43	(1.07,1.92)	1.79	(1.19,2.69)	1.52	(0.93,2.46)	2.50	(1.32,4.74)
p value for trend		0.04		0.01		0.09		0.01

Models are adjusted for age, sex, parental education, family history of asthma, family history of atopy, gestational age, and community.

*Average cigarettes per day

**Average percent of ETS in lifetime