Table 3.
Two- and four-year trajectories by baseline smoking status
| Baseline smoking status | 2-Year transitions, % (95% CI) | 4-Year transitions, % (95% CI) |
| ≤5 CPD, nondaily | 328 smokers, 399 transitions | 164 smokers, 164 transitions |
| Quits | 32 (26–38) | 44 (34–54) |
| Continues nondaily, ≤5 CPD | 48 (41–55) | 31 (22–42) |
| Increases to >5 CPD or daily smoking | 21 (16–26) | 20 (14–29) |
| Mixed trajectorya | NA | 5 (2–10) |
| ≤5 CPD, daily | 147 smokers, 160 transitions | 65 smokers, 65 transitions |
| Quits | 27 (19–37) | 27 (17–41) |
| Reduces to nondaily smoking | 18 (12–26) | 21 (11–34) |
| Continues daily, ≤5 CPD | 21 (15–29) | 7 (3–18) |
| Increases to >5 CPD | 35 (27–43) | 32 (21–46) |
| Mixed trajectorya | NA | 12 (6–24) |
| 6–10 CPD | 440 smokers, 524 transitions | 219 smokers, 219 transitions |
| Quits | 21 (16–26) | 28 (21–35) |
| Reduces to ≤5 CPD | 15 (12–19) | 16 (10–23) |
| Continues 6–10 CPD | 40 (35–45) | 24 (17–33) |
| Increases to >10 CPD | 24 (20–29) | 19 (13–26) |
| Mixed trajectorya | NA | 13 (9–19) |
| >10 CPD | 1,093 smokers, 1,581 transitions | 658 smokers, 658 transitions |
| Quits | 14 (12–16) | 21 (18–26) |
| Reduces to ≤10 CPD | 14 (12–17) | 14 (11–18) |
| Continues >10 CPD | 72 (69–75) | 65 (60–69) |
Note. CPD = cigarettes per day.
a
Mixed trajectory refers to quitting or reducing and then relapsing to more than baseline, or increasing and then decreasing to baseline or less.