Cohort characteristics at recruitment
| Characteristic | No. (%) of participants* | |||
|---|---|---|---|---|
| Participants in analysis of 6-yr risk prediction accuracy for lung cancer at inclusion† n = 11 652 | Missing | Participants in analysis of efficiency of lung cancer screening between 1998 and 2015 n = 8938 | Missing | |
| Age, yr, median (IQR) | 53.9 (48.8–61.0) | 0 | 54.1 (49.0–61.0) | 0 |
| Gender, woman | 5710 (49.0) | 0 | 4260 (47.7) | 0 |
| Highest level of education‡ | 26 (0.2) | 15 (0.2) | ||
| Some high school | 295 (2.4) | 235 (2.6) | ||
| High school graduate | 3274 (28.2) | 2608 (29.2) | ||
| Some college | 3846 (33.1) | 2980 (33.4) | ||
| College graduate | 2073 (17.8) | 1534 (17.2) | ||
| Postgraduate or professional degree | 2138 (18.4) | 1566 (17.6) | ||
| BMI, median (IQR) | 26.9 (24.1–30.3) | 122 (1.1) | 27.1 (24.1–0.5) | 91 (1.0) |
| COPD history | 853 (7.4) | 74 (0.7) | 741 (8.3) | 799 (8.9)§ |
| Cancer history | 1278 (11.0) | 0 | 1055 (11.8) | 0 |
| Family history of lung cancer | 1550 (13.7) | 321 (2.3) | 1251 (14.4) | 258 (2.9) |
| Smoking status | 0 | 0 | ||
| Daily | 2891 (24.8) | 2611 (29.2) | ||
| Occasionally | 880 (76) | 480 (5.37) | ||
| Past | 7881 (67.6) | 5847 (65.4) | ||
| Current no. of cigarettes/d, median (IQR) | 18 (13–23) | 1352 (11.6) | 18 (13–23) | 0¶ |
| Smoking duration, yr, median (IQR) | 24 (12–34) | 1450 (12.4) | 25 (14–35) | 0¶ |
| Smoking quit time,** yr, median (IQR) | 19.9 (10.1–27.9) | 1062 (9.1) | 19.3 (9.79–27.1) | 0¶ |
Note: BMI = body mass index, COPD = chronic obstructive pulmonary disease, IQR = interquartile range.
↵* Unless indicated otherwise.
↵† Prediction cohort: 90% of the cohort for validating the models.
↵‡ Level 3 (some training after high school) unavailable in our cohort.
↵§ Missing age at COPD occurrence.
↵¶ Participants with missing data were excluded.
↵** Time in years since a past smoker stopped smoking.