Table 3

Environmental tobacco smoke (ETS) exposure from the mother at different time points* and personal smoking as risk factors for asthma and wheeze at age 16–17 years

		Physician-diagnosed asthma		Ever wheeze		Current wheeze
		OR	95% CI	OR	95% CI	OR	95% CI
Model A	In utero exposure	1.22	0.94 to 1.59	1.05	0.85 to 1.30	1.16	0.93 to 1.45
	Daily smoking	1.33	0.91 to 1.94	1.87	1.39 to 2.52	1.97	1.46 to 2.67

	ETS at age 7–8 years	1.30	1.02 to 1.67	1.26	1.03 to 1.54	1.19	0.97 to 1.47
	Daily smoking	1.32	0.90 to 1.93	1.88	1.40 to 2.53	1.96	1.45 to 2.66

	ETS at age 16–17 years	1.25	0.96 to 1.63	1.21	0.98 to 1.50	1.15	0.92 to 1.45
	Daily smoking	1.36	0.93 to 1.98	1.89	1.41 to 2.55	1.99	1.47 to 2.70

	Continuous ETS	1.47	1.09 to 1.99	1.34	1.04 to 1.71	1.18	0.91 to 1.54
	Daily smoking	1.35	0.93 to 1.96	1.87	1.39 to 2.50	1.99	1.47 to 2.68

Model B	In utero exposure	1.22	0.82 to 1.82	1.05	0.85 to 1.30	1.16	0.93 to 1.45
	1–10 cigarettes/day	1.22	0.82 to 1.82	1.75	1.29 to 2.38	1.76	1.29 to 2.42
	≥11 cigarettes/day	1.38	0.69 to 2.72	1.94	1.12 to 3.37	2.44	1.41 to 4.22

	ETS at age 7–8 years	1.31	1.02 to 1.68	1.26	1.03 to 1.54	1.19	0.97 to 1.47
	1–10 cigarettes/day	1.18	0.78 to 1.77	1.68	1.23 to 2.29	1.74	1.26 to 2.39
	≥11 cigarettes/day	1.32	0.67 to 2.62	1.98	1.15 to 3.41	2.34	1.35 to 4.05

	ETS at age 16–17 years	1.26	0.96 to 1.64	1.21	0.98 to 1.51	1.15	0.92 to 1.44
	1–10 cigarettes/day	1.22	0.81 to 1.82	1.70	1.24 to 2.31	1.77	1.29 to 2.44
	≥11 cigarettes/day	1.33	0.67 to 2.63	1.96	1.14 to 3.86	2.35	1.35 to 4.07

	Continuous ETS	1.48	1.10 to 2.00	1.34	1.04 to 1.72	1.19	0.91 to 1.55
	1–10 cigarettes/day	1.96	0.80 to 1.78	1.72	1.27 to 2.34	1.74	1.27 to 2.38
	≥11 cigarettes/day	1.47	0.76 to 2.82	2.03	1.19 to 3.46	2.42	1.42 to 4.15

ORs were calculated by multiple logistic regression analyses, adjusting for sex, family history of asthma, current place of residence, house dampness and birth weight <2500 g.
↵* The variables regarding ETS from the mother were included one at a time.