Table 1.

Characteristics of the study participants and biomarker levels in their toenails, plasma, and urine

Characteristic/biomarkernFrequencyMean (SD)Range
Age (y)10438.9 (11.7)19-68
Gender (M/F)10355:48
Race (White/African-American)10351:52
CPD10418 (8.4)5-50
Toenail nicotine (ng/mg)1055.44 (6.41)0.01-33.18
Toenail cotinine (ng/mg)1050.67 (0.79)0.01-3.87
Toenail NNAL (pg/mg)510.18 (0.22)0.01-1.10
Plasma nicotine (ng/mL)789.56 (7.74)0.00-35.40
Plasma cotinine (ng/mL)78198 (134)0-580
Plasma trans-3′-hydroxycotinine (ng/mL)7869.5 (53.1)0-251.8
Urine NNAL (ng/mL)710.24 (0.26)0.01-1.37