Table 1.

Descriptive measures for overall study sample and nicotine metabolism ratio quartiles

OverallQuartile 1Quartile 2Quartile 3Quartile 4
Measures(n = 109)(n = 26)(n = 28)(n = 28)(n = 27)
Descriptive
 Nicotine metabolism ratio0.395 (0.20)0.192 (0.06)0.313 (0.03)0.410 (0.04)0.668 (0.21)
 Cotinine, ng/mL262.8 (110)230.4 (122)308.6 (112)285.5 (110)211.4 (62)
 Sex, % male59.060.067.064.042.0
 Age, y45.4 (10.8)41.3 (11.5)45.6 (11.6)45.7 (8.2)48.8 (11.1)
 Daily cigarette consumption, n20.5 (8.4)19.8 (9.9)18.9 (4.7)21.7 (10.8)22.2 (7.8)
 FTND4.9 (2.1)4.0 (2.1)5.0 (1.7)5.3 (2.3)5.3 (2.1)
 Cigarette type (Reg/Lt/U-Lt), %55/33/1236/56/847/47/639/47/1418/62/20
 Menthol/nonmenthol, % nonmenthol71.056.067.086.076.0
Outcome measures
 Total puff volume, mL785.1 (284.9)683.4 (250.6)740.6 (249.1)840.7 (315.1)875.0 (290.1)
 NNAL, pmol/mg creatinine1.47 (0.79)1.09 (0.63)1.42 (0.70)1.76 (0.97)1.61 (0.71)

NOTE: The values are given as mean (SD), unless noted otherwise. Reg, regular cigarette; Lt, light cigarette; U-Lt, ultralight cigarette, based on Federal Trade Commission (FTC) cigarette classifications used at the time data were collected (FTC, 2000).