Table 3. Odds ratios for secondhand smoke at home (n = 1,738); multiple imputation was applied.

	Model 1		Model 2		Model 3		Model 4
	OR	95% CI	OR	95% CI	OR	95% CI	OR	95% CI
Age, years
20–39	1.00	ref.	1.00	ref.	1.00	ref.	1.00	ref.
40–59	0.55	0.40, 0.75	0.70	0.52, 0.96	0.59	0.43, 0.81	0.61	0.45, 0.85
≥60	0.45	0.32, 0.64	0.78	0.58, 1.05	0.48	0.34, 0.68	0.51	0.35, 0.73
Sex
Men	1.00	ref.	1.00	ref.	1.00	ref.	1.00	ref.
Women	2.65	2.01, 3.50	2.71	2.05, 3.58	2.68	2.03, 3.55	2.79	2.03, 3.83
Education, years
≥13	1.00	ref.			1.00	ref.	1.00	ref.
10–12	2.22	1.65, 2.99			2.03	1.49, 2.76	1.94	1.42, 2.64
≤9	3.68	2.43, 5.56			3.17	2.08, 4.84	3.00	1.95, 4.60
Income
High			1.00	ref.	1.00	ref.	1.00	ref.
Middle			1.28	0.87, 1.90	1.10	0.74, 1.65	1.04	0.69, 1.55
Low			2.12	1.48, 3.02	1.66	1.15, 2.39	1.44	0.98, 2.11
Number of family members							1.09	0.98, 1.20
Smoking status
Cessation smoker							1.00	ref.
Never smoker							0.91	0.66, 1.24
Knowledge
Knowledge of tobacco’s adverse effect							0.95	0.91, 0.98

CI, confidence interval; OR, odds ratio; ref, reference.