Associations between Exposure to Tobacco Smoke and Behavioral Problems in Preschool Japanese Children

Table 2

Associations between current exposure to tobacco smoke and urinary cotinine concentrations.

	n	Percent (%)	Urinary cotinine levels (ng/mg creatinine)
			Geometric mean	95% CI
Number of cigarettes parents currently smoked (cigarettes per day)
0	241	55.1	0.99	(0.15–6.49)	<0.001
>0 to 20	152	34.8	2.30	(0.25–20.93)
>20	44	10.1	5.88	(1.10–31.62)
Number of current smokers among cohabiters (persons)
0	233	53.3	0.94	(0.15–5.78)	<0.001
1	149	34.1	2.09	(0.26–16.68)
≥2	55	12.6	6.79	(1.26–36.70)

CI: confidence interval. ^aBy analysis of variance.