A descriptive analysis of relations between parents' self-reported smoking behavior and infants' daily exposure to environmental tobacco smoke

Table 4 Household smoking, adjusted for infants' sex and age and for study day, and infant cotinine-to-creatinine ratio

	Cotinine-to-creatinine ratio (μg/mmol) with log _e transformation
	B	SE	z	p> \|z\|	95% CI
Household smoking
Smoking outside the home	Ref.
Smoking inside the home	1.42	0.33	4.32	< .001	.77	2.07
Infant's sex and age
Male	Ref.
Female	.79	0.26	3.01	< .01	.28	1.31
Age (month)	-.03	0.01	-2.02	< .05	-.06	-.00
Study day	.03	0.03	1.02	.31	-.03	.08

Generalized estimation equation model to predict the infants' cotinine-to-creatinine ratio (CCR), taking into account cluster correlation within subjects across study days. Model is based on an exchangeable correlation structure for repeated observations within subjects. Predictor variable household smoking was adjusted for infants' age and sex and for study day. Wald chi2 (4) = 40.53, scale parameter = .64. Explained variance of the GEE model was 67.5 percent.

ISSN: 1471-2458