Table 3.

Associations of Parental Smoking With CT Measures of Early Emphysema in the Multi-Ethnic Study of Atherosclerosis, United States, 2000–2006

	No.	Mean (SD)	Unadjusted Model		Adjusted Modela		P for Trend
			Difference	95% CI	Difference	95% CI
Alphab
Neither parent smoked	726	1.24 (0.31)	Reference		Reference		0.04
Only the father smoked	655	1.22 (0.29)	−0.02	−0.05, 0.01	−0.01	−0.04, 0.02
Only the mother smoked	134	1.21 (0.30)	−0.04	−0.09, 0.02	−0.03	−0.08, 0.01
Both parents smoked	247	1.18 (0.32)	−0.06	−0.11, −0.01	−0.04	−0.07, 0.00
Percent emphysemab
Neither parent smoked	726	17.0 (12.0)	Reference		Reference		0.03
Only the father smoked	655	18.1 (12.2)	1.1	−0.2, 2.4	0.7	−0.4, 1.8
Only the mother smoked	134	18.5 (11.9)	1.5	−0.7, 3.7	1.8	−0.1, 3.7
Both parents smoked	247	19.8 (14.1)	2.8	0.9, 4.8	1.6	−0.3, 3.5
Apical-basilar difference in percent emphysema
Neither parent smokedc	726	3.19 (6.98)	Reference		Reference		0.12
Only the father smoked	653	2.16 (6.90)	−1.04	−1.77, −0.30	−0.93	−1.62, −0.24
Only the mother smoked	134	1.67 (7.35)	−1.52	−2.88, −0.18	−0.91	−2.24, 0.42
Both parents smoked	247	1.62 (7.21)	−1.57	−2.61, −0.54	−0.60	−1.59, 0.39

Abbreviations: CI, confidence interval; CT, computed tomography; SD, standard deviation.

^aAdjusted 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.

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

^cThe reference group (neither parent smoked) is compared with 3 mutually exclusive categories of parental smoking (father only, mother only, both parents) modeled as indicator variables, and the trend is assessed for the order given.