Table 3.
Adjusted risk of lung cancer in heavy former vs current smokers*
| YSQ category | Person-exams | Lung cancers | Adjusted hazards ratio† (95% CI) | P‡ |
|---|---|---|---|---|
| Combined cohorts | ||||
| Current smokers (referent) | 14 118 | 137 | 1.00 | − |
| <5 | 2828 | 27 | 0.61 (0.40 to 0.93) | .02 |
| 5 to <10 | 2301 | 27 | 0.59 (0.39 to 0.89) | .01 |
| 10 to <15 | 1564 | 15 | 0.39 (0.23 to 0.67) | <.001 |
| 15 to <25 | 2332 | 22 | 0.29 (0.18 to 0.48) | <.001 |
| 25+ | 1459 | 12 | 0.19 (0.10 to 0.37) | <.001 |
| Original cohort | ||||
| Current smokers (referent) | 9963 | 85 | 1.00 | − |
| <5 | 1882 | 13 | 0.48 (0.27 to 0.87) | .02 |
| 5 to <10 | 1409 | 11 | 0.42 (0.23 to 0.78) | .006 |
| 10 to <15 | 951 | 9 | 0.41 (0.20 to 0.83) | .01 |
| 15 to <25 | 1280 | 12 | 0.31 (0.16 to 0.59) | <.001 |
| 25+ | 770 | 7 | 0.23 (0.10 to 0.54) | <.001 |
| Offspring cohort | ||||
| Current smokers (referent) | 4155 | 52 | 1.00 | − |
| <5 | 946 | 14 | 0.81 (0.44 to 1.48) | .50 |
| 5 to <10 | 892 | 16 | 0.79 (0.45 to 1.40) | .42 |
| 10 to <15 | 613 | 6 | 0.36 (0.15 to 0.85) | .02 |
| 15 to <25 | 1052 | 10 | 0.28 (0.13 to 0.59) | <.001 |
| 25+ | 689 | 5 | 0.15 (0.05 to 0.42) | <.001 |
*
This analysis is limited to current and former smokers with at least 21.3 cumulative pack-years. CI = confidence interval; YSQ = years since quitting.
†
Hazards ratios are adjusted for age, sex, education, examination decade, and alcohol consumption. All variables are time-updated.
‡
P values were derived from a two-sided χ2 test.