Table 2.

Associations of Childhood ETS^a Exposure With CT Measures of Early Emphysema in the Multi-Ethnic Study of Atherosclerosis, United States, 2000–2006

	No.	Mean (SD)	Unadjusted Model		Adjusted Modelb		P for Trend
			Difference	95% CI	Difference	95% CI
Alphac
No childhood ETS exposure	923	1.24 (0.30)	Reference		Reference		0.04
One smoker in the childhood home	559	1.22 (0.30)	−0.02	−0.06, 0.01	−0.01	−0.04, 0.01
Two or more smokers in the childhood home	299	1.19 (0.31)	−0.05	−0.09, −0.01	−0.03	−0.07, 0.00
Percent emphysemac
No childhood ETS exposure	923	17.1 (11.9)	Reference		Reference		0.01
One smoker in the childhood home	559	18.3 (12.5)	1.1	−0.2, 2.4	0.7	−0.4, 1.8
Two or more smokers in the childhood home	299	20.0 (13.5)	2.8	1.1, 4.5	2.1	0.4, 3.7
Apical-basilar difference in percent emphysema
No childhood ETS exposure	922	2.77 (6.92)	Reference		Reference		0.42
One smoker in the childhood home	558	2.36 (7.00)	−0.41	−1.14, 0.33	−0.21	−0.91, 0.50
Two or more smokers in the childhood home	299	1.67 (7.41)	−1.10	−2.05, 0.14	−0.34	−1.24, 0.56

Abbreviations: CI, confidence interval; CT, computed tomography; ETS, environmental tobacco smoke; SD, standard deviation.

^aChildhood ETS was defined by retrospective reports in response to the question, “In your childhood, did you live with a regular cigarette smoker who smoked in your home?” and a follow-up question on the number of smokers in the childhood home.

^bAdjusted for sex, race/ethnicity, age, height, body mass index, whether the participant was born in the United States, mother's and father's educational attainment, participant's educational attainment, history of asthma before age 45 years, cumulative residential air pollution exposure, living with a smoker as an adult, occupational exposures to secondhand smoke and dust, and urinary cotinine.

^cRefer to the Materials and Methods section of the text for a definition.