Lifetime environmental tobacco smoke exposure and the risk of chronic obstructive pulmonary disease

Table 3 Lifetime cumulative ETS exposure and the risk of COPD in a population based sample of 2,113 U.S. adults aged 55 to 75 years

Source of exposure	Level of exposure	Risk of COPD (unadjusted)	Risk of COPD, controlling for smoking	Risk of COPD, controlling for smoking, sociodemographic indicators^†	Risk of COPD, controlling for smoking, sociodemographic indicators, and workplace VGDF^†
		OR (95% CI)	OR (95% CI)	OR (95% CI)	OR (95% CI)
Prenatal	Mother smoked in pregnancy	1.54 (1.01 to 2.33)	1.32 (0.86 to 2.01)	1.41 (0.90 to 2.21)	1.36 (0.86 to 2.14)
Home	1st quartile (0–9 yrs)	1.0 (referent)	1.0 (referent)	1.0 (referent)	1.0 (referent)
	2nd quartile (10–21 yrs)	0.99 (0.69 to 1.41)	0.88 (0.61 to 1.25)	0.92 (0.64 to 1.34)	0.90 (0.62 to 1.31)
	3rd quartile (22–41 yrs)	1.21 (0.86 to 1.70)	0.95 (0.67 to 1.35)	0.95 (0.66 to 1.37)	0.94 (0.65 to 1.36)
	4th quartile (≥42 yrs)	2.69 (1.97 to 3.68)	1.88 (1.35 to 2.61)	1.68 (1.19 to 2.38)	1.55 (1.09 to 2.21)
Work	1st & 2nd quartile (0–5 yrs)*	1.0 (referent)	1.0 (referent)	1.0 (referent)	1.0 (referent)
	3rd quartile (6–22 yrs)	1.14 (0.86 to 1.51)	0.97 (0.73 to 1.30)	1.02 (0.76 to 1.38)	0.91 (0.67 to 1.24)
	4th quartile (≥23 yrs)	1.73 (1.34 to 2.24)	1.34 (1.02 to 1.75)	1.60 (1.20 to 2.14)	1.36 (1.002 to 1.84)

VGDF = self-reported exposure to vapors, gas, dust, or fumes during longest held job
*First and second quartile were both zero, so they were combined as the referent group (otherwise both lower categories would include zero values)
^†Multivariate logistic regression analysis controlling for age, sex, race, smoking history, educational attainment, and marital status. Each source of ETS exposure was evaluated in a separate logistic regression model.

ISSN: 1476-069X