| Parameter | Stratified according to the motivation to change smoking behaviour at baseline* | p Value | ||
| Unmotivated smokers | Ambivalent smokers | Motivated smokers | ||
| n = 557 (55.0%) | n = 327 (32.3%) | n = 128 (12.6%)† | ||
| Age in years, median (range) | 29 (18–72) | 30 (18–73) | 30.5 (19–78) | 0.48‡ |
| Gender, n (%): | ||||
| Male | 339 (60.9) | 192 (58.7) | 83 (64.8) | 0.70§ |
| Female | 218 (39.1) | 135 (41.3) | 45 (35.2) | |
| No. of cigarettes smoked per day during the last 7 days, median (range) | 15 (1–60) | 16 (1–50) | 10 (1–60) | 0.12‡ |
| Nicotine dependency, n (%)¶: | ||||
| Low | 229 (41.1) | 138 (42.2) | 57 (44.5) | 0.49§ |
| Medium | 133 (23.9) | 79 (24.2) | 29 (22.7) | |
| High | 195 (35.0) | 110 (33.6) | 42 (32.8) | |
| Smoking duration, n (%): | ||||
| <1 year | 6 (1.1) | 8 (2.4) | 11 (8.6) | 0.003§ |
| 1–3 years | 45 (8.1) | 23 (7.0) | 13 (10.2) | |
| 4–10 years | 212 (38.1) | 128 (39.1) | 46 (35.9) | |
| >10 years | 294 (52.8)† | 168 (51.4)† | 58 (45.3) | |
| Age of smoking onset, n (%): | ||||
| <14 years | 83 (14.9) | 46 (14.1) | 22 (17.2) | 0.043§ |
| 14–16 years | 224 (40.2) | 112 (34.3) | 39 (30.5) | |
| 17–18 years | 122 (21.9) | 78 (23.9) | 27 (21.1) | |
| 19–30 years | 123 (22.1) | 87 (26.6) | 35 (27.3) | |
| >30 years | 5 (0.9) | 4 (1.2)† | 5 (3.9) | |
| Attempts to quit smoking during the last 12 months, n (%): | ||||
| None | 411 (73.8) | 143 (43.7) | 30 (23.4) | <0.001§ |
| 1 | 89 (16.0) | 97 (29.7) | 46 (35.9) | |
| 2–5 | 44 (7.9) | 80 (24.5) | 35 (27.3) | |
| >5 | 13 (2.3) | 7 (2.1) | 17 (13.3)† | |
| Partner smoking, n (%): | ||||
| No | 134 (24.1) | 99 (30.3) | 47 (36.7) | 0.083 |
| Yes | 261 (46.9) | 130 (39.8) | 43 (33.6) | |
| No partnership | 162 (29.1)† | 98 (30.0)† | 38 (29.7) | |
Significant values are in bold.
*“When do you wish to stop smoking?” (“not within the next 6 months” = unmotivated smokers, “within the next 6 months but not within the next 4 weeks” = ambivalent smokers and “within the next 4 weeks” = motivated smokers); †does not sum up to 100% because of rounding error; ‡Jonckheere–Terpstra test; §Mantel–Haenszel test for trend; ¶measured with the Fagerstroem test for nicotine dependency; “low” = 0–2 points, “medium” = 3–4 points, “high” = 5–10 points.