Background
Methods
Cases and controls
Data collection
Smoking history
Other covariates
Statistical analysis
Results
Selected characteristics of the study population
Men | Women | |||||
---|---|---|---|---|---|---|
Variables | All men (n=1,630) | Cases (n=736) | Controls (n=894) | All women (n=1,075) | Cases (n=464) | Controls (n=611) |
Age (years) - Mean [SD] | 64.6 ± 7.7 | 64.1 ± 7.9 | 65.0 ± 7.6 | 61.6 ± 9.3 | 61.5 ± 9.3 | 61.7 ± 9.3 |
Ethnic origin | ||||||
French | 70.3% | 77.5% | 64.4% | 72.9% | 78.5% | 68.7% |
British Isles | 5.6% | 4.6% | 6.4% | 6.5% | 9.5% | 4.3% |
Italian | 9.4% | 7.3% | 11.1% | 5.3% | 2.8% | 7.2% |
Other European | 8.7% | 6.1% | 10.8% | 6.3% | 4.7% | 7.5% |
Others | 6.0% | 4.5% | 7.3% | 9.0% | 4.5% | 12.3% |
Education | ||||||
Elementary | 39.5% | 44.6% | 35.4% | 30.5% | 36.2% | 26.2% |
Secondary | 42.2% | 42.8% | 41.6% | 47.4% | 51.5% | 44.3% |
Post-secondary | 18.3% | 12.6% | 23.0% | 22.1% | 12.3% | 29.5% |
Family reported income (k$) Mean [SD] | 34.2 [14.5] | 33.0 [14.9] | 35.2 [14.1] | 36.3 [15.4] | 33.7 [15.9] | 38.4 [14.7] |
Respondent type | ||||||
Self | 76.7% | 60.2% | 90.3% | 82.8% | 66.2% | 95.4% |
Proxy | 23.3% | 39.8% | 9.7% | 17.2% | 33.8% | 4.6% |
Histologic type of lung cancer | ||||||
Adenocarcinoma | 32.7% | 46.6% | ||||
Squamous cell carcinoma | 35.5% | 19.6% | ||||
Small cell carcinoma | 17.0% | 17.2% | ||||
Large cell carcinoma | 9.6% | 9.3% | ||||
Others | 5.2% | 7.3% |
Characteristics of smoking histories of lung cancer cases and controls
Men (N=1,630) | Women (N=1,075) | |||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Model | Cigarette smoking variables | Unit or category | Cases | Controls | Cases | Controls | ||||||||
N (%) | Median value | N (%) | Median value | N (%) | Median value | N (%) | Median value | |||||||
a | Ever smoking | No | 18 | (2.5%) | - | 158 | (17.7%) | - | 32 | (6.9%) | - | 309 | (50.6%) | - |
Yes | 718 | (97.5%) | - | 736 | (82.3%) | - | 432 | (93.1%) | - | 302 | (49.4%) | - | ||
Among subjects who ever smoked | ||||||||||||||
b | Age of initiation | In years: Mean [SD] | 15.6 [3.4] | - | 16.8 [4.0] | - | 18.1 [5.4] | - | 20.1 [6.9] | - | ||||
c | Smoking status | Ex-smoker | 225 | (31.3%) | - | 478 | (64.9%) | - | 93 | (21.5%) | - | 170 | (56.3%) | - |
Current smoker | 493 | (68.9%) | - | 258 | (35.1%) | - | 339 | (78.5%) | - | 132 | (43.7%) | - | ||
d | Duration of smoking (in years)a | ]0-20] | 23 | (3.2%) | 15.0 | 141 | (19.2%) | 14.0 | 17 | (3.9%) | 10.0 | 90 | (29.8%) | 11.5 |
]20-30] | 62 | (8.6%) | 26.1 | 154 | (20.9%) | 26.5 | 65 | (15.1%) | 27.1 | 67 | (22.2%) | 26.0 | ||
]30-40] | 178 | (24.8%) | 36.0 | 175 | (23.8%) | 35.0 | 143 | (33.1%) | 35.6 | 80 | (26.5%) | 35.8 | ||
]40-50] | 267 | (37.2%) | 45.1 | 191 | (25.9%) | 45.3 | 143 | (33.1%) | 45.0 | 50 | (16.5%) | 44.9 | ||
>50 | 188 | (26.2%) | 53.0 | 75 | (10.2%) | 53.4 | 64 | (14.8%) | 52.8 | 15 | (5%) | 55.0 | ||
e | Intensity of smoking (cig/day) | ]0-20] | 86 | (12%) | 20.0 | 250 | (34%) | 15.0 | 115 | (26.6%) | 15.0 | 170 | (56.3%) | 10.0 |
]20-30] | 327 | (45.5%) | 25.0 | 279 | (37.9%) | 25.0 | 223 | (51.6%) | 25.0 | 95 | (31.4%) | 25.0 | ||
]30-40] | 91 | (12.7%) | 40.0 | 68 | (9.2%) | 39.5 | 47 | (10.9%) | 35.0 | 18 | (6%) | 37.0 | ||
]40-50] | 144 | (20.1%) | 50.0 | 101 | (13.7%) | 50.0 | 36 | (8.3%) | 50.0 | 15 | (5%) | 50.0 | ||
>50 | 70 | (9.7%) | 75.0 | 38 | (5.2%) | 75.0 | 11 | (2.6%) | 75.0 | 4 | (1.3%) | 62.5 | ||
f | Cumulative amount of smoking (in pack-years)a | ]0-20] | 24 | (3.3%) | 14.0 | 165 | (22.4%) | 10.0 | 28 | (6.5%) | 12.9 | 123 | (40.7%) | 7.1 |
]20-40] | 87 | (12.1%) | 33.7 | 169 | (23%) | 30.0 | 103 | (23.8%) | 32.5 | 95 | (31.4%) | 30.2 | ||
]40-60] | 204 | (28.4%) | 51.5 | 181 | (24.6%) | 49.4 | 178 | (41.2%) | 49.7 | 60 | (19.9%) | 49.7 | ||
]60-80] | 156 | (21.7%) | 65.9 | 111 | (15.1%) | 69.8 | 72 | (16.7%) | 66.3 | 12 | (4%) | 62.9 | ||
]80-100] | 64 | (8.9%) | 90.8 | 46 | (6.2%) | 89.7 | 21 | (4.9%) | 93.7 | 6 | (2%) | 92.5 | ||
>100 | 183 | (25.5%) | 127.2 | 64 | (8.7%) | 125.0 | 30 | (6.9%) | 119.7 | 6 | (2%) | 116.5 | ||
g | CSI indexa | ]0-1] | 33 | (4.6%) | 0.6 | 203 | (27.6%) | 0.6 | 16 | (3.7%) | 0.5 | 113 | (37.4%) | 0.5 |
]1-2] | 192 | (26.7%) | 1.7 | 309 | (42%) | 1.5 | 177 | (41%) | 1.7 | 129 | (42.7%) | 1.5 | ||
]2-2.5] | 288 | (40.1%) | 2.3 | 158 | (21.5%) | 2.2 | 200 | (46.3%) | 2.2 | 52 | (17.2%) | 2.2 | ||
]2.5-3] | 166 | (23.1%) | 2.7 | 55 | (7.5%) | 2.7 | 34 | (7.9%) | 2.7 | 8 | (2.7%) | 2.7 | ||
>3 | 39 | (5.4%) | 3.2 | 11 | (1.5%) | 3.2 | 5 | (1.2%) | 3.1 | 0 | (0%) | - | ||
h | Time since cessation (in years)a | 0b | 493 | (68.7%) | 0 | 258 | (35.1%) | 0 | 339 | (78.5%) | 0 | 132 | (43.7%) | 0 |
]0-5] | 60 | (8.3%) | 2.7 | 51 | (6.9%) | 2.8 | 35 | (8.1%) | 2.4 | 35 | (11.6%) | 2.1 | ||
]5-10] | 50 | (7%) | 8.3 | 67 | (9.1%) | 7.8 | 20 | (4.6%) | 6.8 | 32 | (10.6%) | 7.8 | ||
]10-15] | 41 | (5.7%) | 12.6 | 80 | (10.9%) | 12.8 | 20 | (4.6%) | 12.7 | 19 | (6.3%) | 12.1 | ||
]15-20] | 41 | (5.7%) | 17.4 | 92 | (12.5%) | 17.9 | 11 | (2.5%) | 16.4 | 25 | (8.3%) | 18.1 | ||
>20 | 33 | (4.6%) | 24.7 | 188 | (25.5%) | 28.0 | 7 | (1.6%) | 32.0 | 59 | (19.5%) | 24.8 |
Lung cancer risk in relation to smoking
Model | Cigarette smoking variablesa | Unit or category | ORb [95% CI] | DF | AIC | |
---|---|---|---|---|---|---|
Among men | ||||||
Among all subjects (non-smokers being the reference group) - [N = 1,630 for men] | ||||||
a | Ever smoking | No | 1 | - | 24 | 1907 |
Yes | 7.82 | [4.59 - 13.30] | ||||
b | Smoking status | Non-smoker | 1 | - | 25 | 1796 |
Ex-smoker | 3.99 | [2.31 - 6.87] | ||||
Current smoker | 14.93 | [8.66 - 25.73] | ||||
c | Duration of smoking | 0 | 1 | - | 28 | 1747 |
]0-20] | 1.23 | [0.60 - 2.51] | ||||
]20-30] | 2.98 | [1.61 - 5.51] | ||||
]30-40] | 7.84 | [4.43 - 13.89] | ||||
]40-50] | 12.82 | [7.28 - 22.55] | ||||
>50 | 28.94 | [15.60 - 53.66] | ||||
d | Intensity of smoking | 0 | 1 | - | 27 | 1848 |
]0-20] | 3.18 | [1.78 - 5.68] | ||||
]20-30] | 9.50 | [5.50 - 16.39] | ||||
]30-40] | 9.53 | [5.11 - 17.76] | ||||
>40 | 11.87 | [6.71 – 20.97] | ||||
e | Pack-years | 0 | 1 | - | 29 | 1762 |
]0-20] | 1.33 | [0.67 - 2.66] | ||||
]20-40] | 3.99 | [2.21 - 7.19] | ||||
]40-60] | 9.46 | [5.38 - 16.62] | ||||
]60-80] | 13.14 | [7.30 - 23.63] | ||||
]80-100] | 11.13 | [5.74 - 21.56] | ||||
>100 | 23.64 | [12.87 - 43.40] | ||||
f | CSI index | 0 | 1 | - | 27 | 1721 |
]0-1] | 1.52 | [0.79 - 2.89] | ||||
]1-2] | 5.13 | [2.96 - 8.89] | ||||
]2-2.5] | 14.80 | [8.47 - 25.83] | ||||
>2.5 | 24.35 | [13.38 - 44.30] | ||||
Among subjects who ever smoked (current smokers or subjects who quit smoking less than 2 years before the reference date being the reference group) - [N = 1,461 for men] | ||||||
g | Time since cessation | 0 | 1 | - | 26 | 1646 |
]0-10] | 0.45 | [0.31 - 0.63] | ||||
]10-20] | 0.27 | [0.19 - 0.38] | ||||
>20 | 0.10 | [0.06 - 0.17] | ||||
Among women | ||||||
Among all subjects (non-smokers being the reference group) - [N = 1,075 for women] | ||||||
a | Ever smoking | No | 1.00 | - | 16 | 1066 |
Yes | 11.76 | [7.50 - 18.42] | ||||
b | Smoking status | Non-smoker | 1.00 | - | 17 | 1001 |
Ex-smoker | 4.80 | [2.90 - 7.93] | ||||
Current smoker | 21.33 | [13.23 - 34.38] | ||||
c | Duration of smoking | 0 | 1.00 | - | 19 | 978 |
]0-20] | 1.51 | [0.74 - 3.04] | ||||
]20-30] | 6.37 | [3.55 - 11.41] | ||||
]30-40] | 13.64 | [8.19 - 22.74] | ||||
>40 | 28.79 | [16.86 - 49.16] | ||||
d | Intensity of smoking | 0 | 1.00 | - | 18 | 1028 |
]0-20] | 6.05 | [3.70 - 9.90] | ||||
]20-30] | 19.40 | [11.81 - 31.86] | ||||
>30 | 18.20 | [10.10 - 32.80] | ||||
e | Pack-years | 0 | 1.00 | - | 19 | 950 |
]0-20] | 2.04 | [1.11 - 3.74] | ||||
]20-40] | 8.66 | [5.10 - 14.68] | ||||
]40-60] | 25.48 | [15.08 - 43.04] | ||||
>60 | 37.39 | [19.79 - 70.62] | ||||
f | CSI index | 0 | 1.00 | - | 18 | 946 |
]0-1] | 1.25 | [0.62 - 2.51] | ||||
]1-2] | 11.98 | [7.32 - 19.62] | ||||
>2 | 29.66 | [17.67 - 49.80] | ||||
Among subjects who ever smoked (current smokers or subjects who quit smoking less than 2 years before the reference date being the reference group) - [N = 738 for women] | ||||||
g | Time since cessation | 0 | 1.00 | - | 17 | 799 |
]0-10] | 0.32 | [0.20 - 0.51] | ||||
>10 | 0.15 | [0.09 - 0.26] |
Model | Cigarette smoking variablesa | Unit | β estimate | ORb (95% CI) | DF | AIC | Δ AICc |
---|---|---|---|---|---|---|---|
Among men who ever smoked [N = 1 454] | |||||||
1 | Duration (Dur) | per year | (7.7 x 10-2) x Dur | 1.08 [1.06 - 1.10] | 24 | 1630 | - |
2 | Intensity (Int) | per pack | 0.84 x Log(Int) | 2.31 [1.85 - 2.89] | 24 | 1731 | -22 |
3* | Pack-years (PY) | per pack-year | 1.06 x Log(PY) | 2.87 [2.35 - 3.52] | 24 | 1646 | -39 |
4 | CSI index (CSI) | per unit | 1.31 x CSI | 3.70 [3.04 - 4.50] | 24 | 1583 | - |
5 | Duration (Dur) | per year | (7.2 x 10-2) x Dur | 1.07 [1.06 - 1.09] | 25 | 1602 | -8 |
Intensity (Int) | per pack | 0.64 x Log(Int) | 1.90 [1.49 - 2.42] | ||||
6 | Duration (Dur) | per year |
variable not retained in the final model
| 25 | 1600 | -10 | |
Intensity (Int) | per pack | 0.75 x Log(Int) | 2.12 [1.66 - 2.70] | ||||
Time since cess. (TSC) | per year | (-7.9 x 10-2) x TSC | 0.92 [0.91 - 0.94] | ||||
7 | Pack-years (PY) | per pack-year | 0.75 x Log(PY) | 2.11 [1.70 - 2.61] | 25 | 1588 | -19 |
Time since cess. (TSC) | per year | -0.4 x Log(TSC) | 0.67 [0.60 - 0.75] | ||||
Among women who ever smoked [N = 734] | |||||||
1* | Duration (Dur) | per year | (8.1 x 10-2) x Dur | 1.08 [1.06 - 1.11] | 17 | 781 | - |
2* | Intensity (Int) | per pack | 1.22 x Log(Int) | 3.40 [2.47 - 4.66] | 17 | 792 | -33 |
3 | Pack-years (PY) | per year | 1.15 x Log(PY) | 3.17 [2.41 - 4.16] | 17 | 755 | -21 |
4 | CSI index (CSI) | per unit | 1.74 x CSI | 5.68 [4.02 - 8.00] | 17 | 735 | - |
5* | Duration (Dur) | per year | (6.8 x 10-2) x Dur | 1.07 [1.04 - 1.10] | 18 | 743 | -16 |
Intensity (Int) | per pack | 1.05 x Log(Int) | 2.87 [2.02 - 4.08] | ||||
6* | Duration (Dur) | per year | (3.8 x 10-2) x Dur | 1.04 [1.00 - 1.08] | 19 | 739 | -16 |
Intensity (Int) | per pack | 1.13 x Log(Int) | 3.09 [2.15 - 4.45] | ||||
Time since cess. (TSC) | per year | (-5.0 x 10-2) x TSC | 0.95 [0.91 - 0.99] | ||||
7* | Pack-years (PY) | per pack.year | 0.97 x Log(PY) | 2.63 [1.97 - 3.51] | 18 | 741 | -12 |
Time since cess. (TSC) | per year | -0.36 x Log(TSC) | 0.70 [0.58 - 0.84] |
Histological types
All histologies combined | Squamous cell carcinoma | Small cell carcinoma | Adenocarcinoma | Large cell carcinoma | ||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Model | Cigarette smoking variablesa | Category | N (controls) | N (cases) | ORb [95% CI] | N (cases) | ORb [95% CI] | N (cases) | ORb [95% CI] | N (cases) | ORb [95% CI] | N (cases) | ORb [95% CI] | |||||
Among all subjects (non-smokers being the reference group) | ||||||||||||||||||
a | Ever smoking | No | 467 | 50 | 1 | - | 12 | 1 | - | 0 | 1 | - | 26 | 1 | - | 4 | 1 | - |
Yes | 1038 | 1150 | 9.56 | [6.88 - 13.30] | 340 | 9.44 | [5.14 - 17.35] | 205 | Undefined | 431 | 8.48 | [5.46 - 13.17] | 110 | 11.27 | [3.94 - 32.18] | |||
b | Smoking status | Non-smoker | 467 | 50 | 1 | - | 12 | 1 | - | 0 | 1 | - | 26 | 1 | - | 4 | 1 | - |
Ex-smoker | 648 | 318 | 4.47 | [3.15 - 6.34] | 115 | 4.99 | [2.65 - 9.40] | 39 | Undefined | 122 | 4.02 | [2.51 - 6.44] | 22 | 3.86 | [1.25 - 11.88] | |||
Current smoker | 390 | 832 | 17.59 | [12.47 - 24.79] | 225 | 17.38 | [9.31 - 32.44] | 166 | 309 | 15.16 | [9.62 - 23.89] | 88 | 24.10 | [8.25 - 70.37] | ||||
c | Duration of smoking | 0 | 467 | 50 | 1 | - | 12 | 1 | - | 0 | 1 | - | 26 | 1 | - | 4 | 1 | - |
]0-30] | 452 | 167 | 3.07 | [2.11 - 4.47] | 32 | 2.20 | [1.09 - 4.44] | 28 | Undefined | 76 | 3.00 | [1.82 - 4.94] | 19 | 3.81 | [1.21 - 12.01] | |||
]30-40] | 255 | 321 | 10.91 | [7.57 - 15.74] | 93 | 10.67 | [5.58 - 20.39] | 57 | 121 | 9.97 | [6.10 - 16.27] | 32 | 15.14 | [4.92 - 46.58] | ||||
>40 | 331 | 662 | 22.20 | [15.42 - 31.96] | 215 | 21.23 | [11.21 - 40.20] | 120 | 234 | 21.25 | [12.99 - 34.75] | 59 | 33.24 | [10.52 - 105.05] | ||||
d | Intensity of smoking | 0 | 467 | 50 | 1 | - | 12 | 1 | - | 0 | 1 | - | 26 | 1 | - | 4 | 1 | - |
]0-20] | 420 | 201 | 4.79 | [3.34 - 6.87] | 43 | 3.59 | [1.83 - 7.05] | 39 | Undefined | 87 | 4.46 | [2.75 - 7.22] | 20 | 5.87 | [1.90 - 18.10] | |||
]20-30] | 374 | 550 | 14.12 | [9.93 - 20.08] | 148 | 13.80 | [7.32 - 26.00] | 90 | 231 | 14.26 | [8.92 - 22.79] | 54 | 18.03 | [6.04 - 53.75] | ||||
>30 | 244 | 399 | 15.31 | [10.53 - 22.26] | 149 | 17.59 | [9.19 - 33.65] | 76 | 113 | 11.22 | [6.75 - 18.65] | 36 | 17.20 | [5.46 - 54.10] | ||||
e | Pack-years | 0 | 467 | 50 | 1 | - | 12 | 1 | - | 0 | 1 | - | 26 | 1 | - | 4 | 1 | - |
]0-30] | 423 | 119 | 2.94 | [2.01 - 4.31] | 28 | 2.52 | [1.24 - 5.11] | 19 | Undefined | 55 | 2.85 | [1.71 - 4.76] | 9 | 2.56 | [0.74 - 8.84] | |||
]30-60] | 370 | 505 | 13.60 | [9.55 - 19.35] | 118 | 11.08 | [5.85 - 20.93] | 82 | 229 | 14.50 | [9.06 - 23.19] | 50 | 19.28 | [6.36 - 58.37] | ||||
>60 | 245 | 526 | 24.16 | [16.57 - 35.41] | 194 | 26.40 | [13.76 - 50.63] | 104 | 147 | 17.96 | [10.75 - 30.01] | 51 | 40.61 | [12.58 - 131.09] | ||||
f | CSI index | 0 | 467 | 50 | 1 | - | 12 | 1 | - | 0 | 1 | - | 26 | 1 | - | 4 | 1 | - |
]0-1] | 316 | 49 | 1.64 | [1.05 - 2.56] | 11 | 1.20 | [0.51 - 2.82] | 5 | Undefined | 22 | 1.61 | [0.87 - 2.96] | 4 | 1.54 | [0.36 - 6.51] | |||
]1-2] | 438 | 369 | 8.19 | [5.76 - 11.64] | 101 | 7.96 | [4.20 - 15.07] | 59 | 155 | 7.79 | [4.86 - 12.47] | 36 | 10.87 | [3.58 - 33.01] | ||||
>2 | 284 | 732 | 24.68 | [17.22 - 35.37] | 228 | 23.90 | [12.68 - 45.04] | 141 | 254 | 22.50 | [13.91 - 36.39] | 70 | 37.04 | [12.03 - 114.04] |