Table 2. Smoking behavior and biomarkers of exposure while smoking reduced nicotine cigarettes means.
| Characteristic | Baseline (usual) | 6 Months (1 mg) | 12 Months (1mg) | 18 Months | 24 Months | Significant Interactions |
|---|---|---|---|---|---|---|
| Control (n=55) | Control (n=50) | Control (n=48) | Control (n=40) | Control (n=38) | ||
| Research (n=80) | Research (n=53) | Research (n=37) | Research (n=32) | Research (n=30) | ||
| Cigarettes per day† | 20 (18, 22) | 22 (19, 25) | 21 (18, 23) | 17 (14, 20) a,b,c | 16 (14, 19) a,b,c | 6M v. BL, 24M v. BL |
| 23 (21, 25) | 20 (17, 23) | 22 (18, 25) | 17 (14, 21) a,b,c | 13 (9, 17) a,c | ||
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| Plasma cotinine ng/mL† | 268 (233, 302) | 239 (202, 278) a | 267 (223, 310) | 238 (192, 284) | 209 (174, 244) a,c | 6M v. BL, 12M v. BL |
| 250 (222, 277) | 113 (81, 145) a | 149 (110, 188) a | 210 (170, 250) b,c | 173 (135, 211) c | 18M v. 6M, 24M v. 6M | |
| 18M v. 12 M, 24M v. 12M | ||||||
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| Expired CO (ppm) † | 22 (19, 2) | 20 (17, 23) | 23 (20, 26) | 20 (18, 24) | 19 (15, 22) | NS |
| 25 (22, 28) | 23 (19, 26) | 23 (19, 27) | 22 (17, 27) | 20 (15, 24) | ||
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| Urine (pmol/mg creatinine) | ||||||
| Total NNAL* | 1.0 (0.7, 1.3) | 0.9 (0.6, 1.2) | 0.8 (0.7, 0.9) | 0.6 (0.4, 0.7) | 6M v. BL | |
| 1.4 (1.1, 1.7) | 0.8 (0.5, 1.1)a | 0.8 (0.7, 0.9) a | 0.7 (0.6, .09) | |||
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| Sum of phenanthrenes* | 3.5 (2.8, 4.4) | 4.0 (3.3, 4.7) | 4.0 (1.1, 7.0) | NS | ||
| 4.0 (3.3, 4.7) | 3.9 (3.1, 4.8) | 3.8 (2.0, 6.1) | ||||
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| 2-naphthol* | 97 (73, 129) | 112 (92, 136) | 105 (102, 108) | NS | ||
| 161 (123, 210) | 137 (107, 174) | 115 (113, 117) | ||||
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| 2-hydroxyfluorene* | 13 (10, 17) | 15 (12, 18) | 14 (12, 16) | NS | ||
| 17 (14, 22) | 17 (13, 23) | 16 (14, 18) | ||||
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| 1-hydroxypyrene* | 1.1 (0.9, 1.5) | 1.4 (1.1, 1.6) | 1.5 (0.6, 3.0) | NS | ||
| 1.4 (1.1, 1.7) | 1.5 (1.2, 1.9) | 1.4 (0.4, 3.0) | ||||
*
geometric means (95% C.I.);
†
arithmetic means (95% C.I.)
a
significantly different from Baseline, p<0.005
b
significantly different from 6 Months, p<0.005
c
significantly different from 12 Months, p<0.005