Table 3.
Incident smoking-related cancera risk by age at cessation and duration of smoking among former smokers who reported consistent < 1 or 1–10 cigarettes per day (CPD) over the time they smoked
| N | Cases | Adjusted HR (95% CI)b | Excluding ever regular users of cigars/pipesc | |
|---|---|---|---|---|
| Never smoker | 93,171 | 2,748 | 1.00 | 1.00 |
|
| ||||
| Former consistent < 1 CPD | ||||
| All | 4,827 | 156 | 1.09 (0.93 – 1.28) | 1.11 (0.92 – 1.34) |
| Years since cessation | ||||
| < 10 y | 104 | 3 | 1.05 (0.34 – 3.27) | 1.32 (0.33 – 5.26) |
| 10 – 19 y | 573 | 17 | 1.14 (0.71 – 1.83) | 0.98 (0.54 – 1.77) |
| 20 – 29 y | 655 | 28 | 1.47 (1.01 – 2.13) | 1.49 (0.95 – 2.34) |
| 30 – 39 y | 1,416 | 42 | 1.17 (0.86 – 1.59) | 1.02 (0.69 – 1.51) |
| ≥ 40 y | 2,079 | 66 | 0.92 (0.72 – 1.18) | 1.07 (0.82 – 1.42) |
| Duration of smoking | ||||
| ≤ 10 y | 3,596 | 110 | 0.99 (0.82 – 1.21) | 1.07 (0.86 – 1.34) |
| 11 – 20 y | 673 | 25 | 1.21 (0.82 – 1.80) | 1.18 (0.72 – 1.94) |
| 21 – 30 y | 213 | 13 | 1.36 (0.79 – 2.35) | 1.35 (0.68 – 2.71) |
| > 30 y | 179 | 6 | 1.09 (0.49 – 2.43) | 0.89 (0.29 – 2.77) |
|
| ||||
| Former consistent 1–10 CPD | ||||
| All | 16,849 | 574 | 1.15 (1.05 – 1.26) | 1.15 (1.04 – 1.27) |
| Years since cessation | ||||
| < 10 y | 696 | 42 | 2.28 (1.68 – 3.09) | 2.35 (1.66 – 3.33) |
| 10 – 19 y | 2,139 | 70 | 1.18 (0.93 – 1.50) | 1.14 (0.87 – 1.49) |
| 20 – 29 y | 3,228 | 116 | 1.29 (1.07 – 1.55) | 1.30 (1.05 – 1.61) |
| 30 – 39 y | 5,799 | 164 | 1.03 (0.88 – 1.21) | 1.04 (0.86 – 1.25) |
| ≥ 40 y | 4,987 | 182 | 1.04 (0.89 – 1.21) | 1.05 (0.88 – 1.25) |
| Duration of smoking | ||||
| ≤ 10 y | 9,235 | 279 | 1.02 (0.90 – 1.15) | 1.03 (0.89 – 1.19) |
| 11 – 20 y | 3,854 | 139 | 1.17 (0.98 – 1.39) | 1.17 (0.95 – 1.43) |
| 21 – 30 y | 2,335 | 91 | 1.28 (1.04 – 1.58) | 1.34 (1.06 – 1.69) |
| > 30 y | 1,381 | 64 | 1.50 (1.17 – 1.92) | 1.45 (1.10 – 1.92) |
HR: hazard ratio, CI: confidence interval
Cancer of oral cavity, oropharynx, nasopharynx, hypopharynx, esophagus, stomach, colorectum, liver, pancreas, nasal cavity, paranasal sinuses, larynx, lung, uterine cervix, ovary (mucinous) urinary bladder, kidney, ureter, and acute myeloid leukemia.
Adjusted for gender, race/ethnicity (non-Hispanic white, non-Hispanic black, Hispanic, Asian/pacific islander/native American, or unknown), education (< high school, high school, post high school, some college, college/post graduate, or unknown), alcohol intake (continuous), familial history of any cancer (yes, no, or unknown), and ever regular use of pipe or cigar (yes, no, or unknown). Age was used as the underlying time metric.
Excluding participants who reported ever using pipes or cigars regularly in the 1995–1996 initial cohort questionnaire.