| Mean (SD) age (years) | 42.9 (10.5) | 42.9 (12.0) |
| Mean (SD) height (cm) | 171.9 (9.6) | 171.6 (9.2) |
| Mean (SD) weight (kg) | 76.4 (15.9) | 75.6 (14.1) |
| Gender (%) | | |
| Male | 48.4 | 50.0 |
| Female | 51.6 | 50.0 |
| Race (%) | | |
| Caucasian | 92.6 | 93.5 |
| Black | 2.9 | 1.6 |
| Asian | 2.1 | 2.4 |
| Other | 2.4 | 2.4 |
| Mean (range) duration of smoking (years) | 25.9 (2–58) | 25.2 (1–62) |
| Mean (range) cigarettes per day over last month (n) | 23.0 (15–80) | 22.4 (11–60) |
| 1 or more previous serious quit attempts (%) | 86.1 | 89.7 |
| Previous attempts with nicotine patch (%) | 48.5 | 46.2 |
| Previous attempts with bupropion (%) | 19.7 | 20.0 |
| Mean (range) longest previous period of abstinence (days) | 5.64 (0–90) | 7.49 (0–90) |
| Mean (SD) Fagerström test for nicotine dependence score | 5.62 (2.23) | 5.37 (1.99) |