Table 3.

Longer term secondhand smoke exposure as measured by NNAL and COPD-related health status (n = 72)

	Mean change in outcome	Mean change in outcome
Health outcome measurement	Unadjusted	Adjusteda
COPD severity (points)	1.8 (0.8–2.9), p = .0008	1.7 (0.6–2.8), p = .003
Physical health status (points)	−2.3 (−4.2 to −0.4), p = .019	−1.9 (−3.8 to −0.1), p = .04
Disease-specific health-related quality of life (points)	0.8 (−0.003 to 1.6), p = .051	0.5 (−0.3 to 1.3), p = .19
Dyspnea (points)	0.24 (0.04–0.4), p = .018	0.20 (0–0.39), p = .051
Restricted activity days due to respiratory condition (during past 30 days)	3.3 (1.4–5.3), p = .001	3.2 (1.1–5.3), p = .003

Note. COPD = chronic obstructive pulmonary disease; NNAL = 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol.

^aMultivariate analysis controls for age, sex, race, educational attainment, and past smoking (all subjects are current nonsmokers). Results are mean change in health status variable per 0.0.043 pmol/mg increase in NNAL/creatinine ratio (i.e., interquartile range) and 95% CI.