Directly measured secondhand smoke exposure and COPD health outcomes

BMC Pulmonary Medicine

Table 4 Cross-sectional association between directly measured SHS exposure and COPD-related health status (n = 77).

SHS exposure	COPD severity		Physical health status (SF-12)		Disease-specific QOL		Dyspnea
	Bivariate	Multivariate	Bivariate	Multivariate	Bivariate	Multivariate	Bivariate	Multivariate
Urine cotinine
1^st tertile	Referent	Referent	Referent	Referent	Referent	Referent	Referent	Referent
2^nd tertile	1.2 (-2.5 to 4.8)	0.2 (-3.6 to 3.9)	-2.3 (-8.9 to 4.2)	0.4 (-5.6 to 6.5)	-0.4 (-3.2 to 2.4)	-0.7 (-3.5 to 2.0)	-0.1 (-0.7 to 0.6)	-0.3 (-0.9 to 0.3)
3^rd tertile	5.4 (1.4 to 9.3)	4.7 (0.6 to 8.9)	-7.8 (-14.9 to -0.7)	-5.6 (-12 to 1.0)	2.9 (-0.16 to 6.0)	2.3 (-0.7 to 5.4)	1.1 (0.5 to 1.8)	1.0 (0.4 to 1.7)
Nicotine badge
1^st tertile	Referent	Referent	Referent	Referent	Referent	Referent	Referent	Referent
2^nd tertile	0.2 (-3.6 to 3.9)	0.6 (-3.2 to 4.4)	3.0 (-3.7 to 9.8)	2.7 (-3.4 to 8.8)	-1.6 (-4.5 to 1.4)	-1.7 (-4.6 to 1.2)	-0.2 (-0.8 to 0.5)	-0.2 (-0.8 to 0.4)
3^rd tertile	-1.4 (-5.3 to 2.5)	-1.1 (-5.0 to 2.8)	3.2 (-3.8 to 10.1)	1.9 (-4.3 to 8.2)	-2.1 (-5.1 to 0.9)	-1.6 (-4.5 to 1.3)	-0.2 (-0.9 to 0.5)	-0.1 (-0.7 to 0.5)

All values are mean score change compared to lowest exposure tertile (referent group) and 95% confidence interval. 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. Boldface = p < 0.05.

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