Table 2.

Biomarker Intercorrelations

	Normalized urinary nicotine, ng/mg	Normalized urinary cotinine, ng/mg	Normalized urinary NNAL, pg/mg
Cigarettes per day on days smoked	0.30*	0.34*	0.39**
Total cigarettes/8 days	0.32*	0.33*	0.23
Normalized urinary nicotine, ng/ml	–	0.76**	0.70**
Normalized urinary cotinine, ng/mg	–	1.0**	0.84**

Note. NNAL = 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol. Spearman’s Rho correlations are reported.

*p < .05. **p < .01.