Directly measured secondhand smoke exposure and COPD health outcomes

BMC Pulmonary Medicine

Table 3 Impact of self-reported SHS exposure (past 7 days) on COPD-related health status among 77 adults with COPD: cross-sectional and prospective analysis

SHS exposure, past 7d	COPD severity		Physical health status (SF-12)		Disease-specific QOL		Dyspnea
	Bivariate	Multivariate	Bivariate	Multivariate	Bivariate	Multivariate	Bivariate	Multivariate
Cross-sectional analysis (n = 77)
None	Referent	Referent	Referent	Referent	Referent	Referent	Referent	Referent
1–3 hrs	1.0 (-3.2 to 5.2)	1.7 (-2.7 to 6.2)	-0.6 (-8.1 to 6.9)	-5.9 (-12.8 to 1.0)^‡‡	2.4 (-0.7 to 5.5)	3.6 (0.4 to 6.7)	0.5 (-0.3 to 1.2)	1.1 (0.3 to 1.8)
≥4 hrs	4.1 (-0.91 to 9.0)^†	3.8 (-1.2 to 8.8)	-1.5 (-10.4 to 7.4)	-1.3 (-9.1 to 6.6)	1.0 (-2.8 to 4.8)	1.2 (-2.4 to 4.7)	0.2 (-0.7 to 1.1)	0.2 (-0.6 to 1.0)
Impact of baseline SHS exposure on prospective outcomes at 1 year (n = 68)
None	Referent	Referent	Referent	Referent	Referent	Referent	Referent	Referent
1–3 hrs	3.2 (-1.2 to 7.7)	3.6 (-1.1 to 8.2)	-5.7 (-13.2 to 1.8)	-7.2 (-14.9 to 0.5) ^‡	2.5 (-0.9 to 5.8)	3.4 (0.3 to 6.5)	0.9 (0.2 to 1.7)	1.2 (0.5 to 1.8)
≥4 hrs	4.9 (-0.2 to 9.9)*	4.1 (-1.1 to 9.2)^††	-6.5 (-15.0 to 2.1)	-4.9 (-13.5 to 3.7)	2.6 (-1.2 to 6.4)	1.6 (-1.8 to 5.1)	0.4 (-0.4 to 1.3)	0.2 (-0.5 to 1.0)

Values are mean score change compared to lowest exposure tertile (referent group) and 95% confidence interval. The lower and higher SHS exposure groups were defined based on the median among those with any exposure. Multivariate analysis controls for age, sex, race, educational attainment, and past smoking history. Physical health status was measured by the SF-12 physical component summary score; Disease-specific QOL was measured by the Airways Questionnaire 20 (AQ-20); Dyspnea was measured by the modified MRC Dyspnea Scale. Higher scores = worse status, except for SF-12 physical score. There were 57 subjects, 12 subjects, and 8 subjects in the none, 1–3 hrs, and ≥4 hrs/week exposure groups, respectively.
Boldface = p < 0.05.
*p = 0.06 ^‡P = 0.07 ^‡‡p = 0.09 ^†p = 0.11 ^††p = 0.12

ISSN: 1471-2466