Table 4

Lung function with exposure to environmental tobacco smoke measured from a combination of questionnaire and serum cotinine

Self reported environmental tobacco smoke and serum cotinine		Residual				Case-control
		Mean	95% CI			OR^4-150	95% CI	OR^4-151	95% CI
FEV₁:
Low exposure^4-152	0.158	2.238 to 0.293		1.00		1.00
Middle exposure^4-152	−0.018	−0.859 to 0.050		2.88	1.42 to 5.84	2.91	1.43 to 5.91
High exposure^4-152	−0.032	−0.126 to 0.062		3.12	1.39 to 6.99	3.15	1.40 to 7.07
FVC:
Low exposure^4-152	0.196	0.031 to 0.360		1.00		1.00
Middle exposure^4-152	−0.005	−0.093 to 0.082		2.08	1.02 to 4.21	2.01	0.99 to 4.09
High exposure^4-152	−0.070	−0.187 to 0.047		2.56	1.15 to 5.72	2.49	1.11 to 5.58

↵4-150 OR adjusted for sex, deprivation score, and total energy intake.
↵4-151 OR further adjusted for respiratory symptoms.
↵4-152 The 1st, 2nd and 3rd tertile values for cotinine concentrations (ng/ml) were 0, 0.01–1.02 and 1.03–17.49; for exposure hours a day they were <1, 1–2 and >2; and for total environmental tobacco smoke scores they were 3–4, 5–6 and 7–12. They were scored at 1, 2, and 3 respectively. Those with scores 3–4 were defined as low exposure to environmental tobacco smoke (n=48), scores 5–7 as middle exposure (n=160), and scores 8–9 as high exposure (n=70).