Table 1. Outcome Measures by Cigarette Use Periods, Collapsed Across Nicotine Metabolism Groups.
| Outcome | Cigarette Use Period, Mean (95% CI)a | ||
|---|---|---|---|
| Preferred Brand | RNC1 | RNC2 | |
| Smoking behaviors | |||
| Daily cigarette consumption, No.b,c | 13.9 (12.5-15.2) | 16.5 (14.9-18.1) | 14.8 (13.2-16.5) |
| Total puff volume, mLb,c,d | 744 (681-806) | 537 (479-595) | 598 (547-649) |
| Puff count, No.b,c,d | 14.7 (13.6-15.9) | 11.2 (10.4-11.9) | 12.3 (11.5-13.1) |
| Mean puff volume, mL | 52.7 (48.1-57.4) | 49.4 (44.4-54.3) | 50.1 (45.5-54. 6) |
| Mean puff duration, sc,d | 1.7 (1.6-1.8) | 1.7 (1.5-1.8) | 1.8 (1.7-2.0) |
| Interpuff interval, sb,c,d | 26.1 (23.2-28.9) | 22.3 (19.7-24.8) | 20.7 (18.2-23.2) |
| Peak velocity, mL/sb,c,d | 46.0 (42.7-49.4) | 43.4 (39.8-46.9) | 41.1 (37.9-44.4) |
| Biomarkers of exposure | |||
| Onset CO level, ppm | 19.1 (17.0-21.3) | 19.4 (17.0-21.9) | 19.7 (17.1-22.4) |
| CO boost, ppmc | 4.4 (3.8-4.9) | 4.6 (4.1-5.1) | 4.2 (3.7-4.6) |
| NNAL, pg/mg creatinineb,c,d | 280 (231-339) | 229 (189-277) | 190 (157-231) |
| TNE, nmoL/mg creatinineb,c,d | 54.6 (48.1-62.1) | 30.9 (26.0-36.6) | 22.8 (17.8-29.0) |
Abbreviations: CO, carbon monoxide; NNAL, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol; RNC, reduced nicotine content of 5.2 mg (RNC1) and 1.3 mg (RNC2) of nicotine per gram of tobacco; TNE, total nicotine equivalent.
a
Data are presented as arithmetic mean (95% CI) except for NNAL and TNE, which are presented as geometric mean (95% CI).
b
Statistically significant difference between preferred brand and RNC1 cigarette periods at the P < .05 level.
c
Significant difference between RNC1 and RNC2 cigarette periods at the P < .05 level.
d
Significant difference between preferred brand and RNC2 cigarette periods at the P < .05 level.