Table 2.
Selected characteristics of participants
| Characteristic | Cases (n = 4172) N (%) |
Controls (n = 8471) N (%) |
P value (X2) |
|---|---|---|---|
| Sex | 0.37 | ||
| Men | 3043 (72.9) | 6135 (72.4) | |
| Women | 1129 (27.1) | 2336 (27.6) | |
| Age | <.0001 | ||
| < 45 | 76 (1.8) | 197 (2.3) | |
| 45–49 | 211 (5.1) | 980 (11.6) | |
| 50–54 | 602 (14.4) | 1720 (20.3) | |
| 55–59 | 1010 (24.2) | 2165 (25.5) | |
| 60–64 | 1216 (29.2) | 2024 (23.9) | |
| 65–69 | 731 (17.5) | 1070 (12.6) | |
| ≥ 70 | 326 (7.8) | 324 (3.8) | |
| BMI (kg/m2) a | <.0001 | ||
| Underweight | 250 (5.9) | 408 (4.8) | |
| Normal weight | 2150 (51.5) | 4276 (50.5) | |
| Overweight | 112 (26.7) | 2746 (32.4) | |
| Obese | 373 (8.9) | 934 (11.0) | |
| Missing | 287 (6.9) | 107 (1.3) | |
| Education | <.0001 | ||
| None | 529 (12.7) | 699 (8.3) | |
| Primary | 1515 (36.3) | 2518 (29.7) | |
| Middle/Vocational | 851 (20.4) | 2109 (24.9) | |
| Secondary | 457 (11.0) | 1060 (12.5) | |
| Postsecondary/Technical | 312 (7.5) | 665 (7.9) | |
| University | 381 (9.1) | 1164 (13.7) | |
| Unknown/not specified | 26 (0.6) | 51 (0.6) | |
| Missing | 101 (2.4) | 205 (2.4) | |
| Smoking status | <.0001 | ||
| Never | 571 (13.7) | 3144 (37.1) | |
| Former | 694 (16.6) | 1735 (20.5) | |
| Current | 2892 (69.3) | 3556 (42.0) | |
| Missing b | 15 (0.36) | 36 (0.4) | |
| Pack-years of smoking | <.0001 | ||
| 0 | 571 (13.7) | 3144 (37.1) | |
| < 20 | 547 (13.1) | 1562 (18.4) | |
| 20–29 | 554 (13.3) | 850 (10.0) | |
| 30–39 | 691 (16.6) | 891 (10.5) | |
| 40–49 | 817 (19.6) | 829 (9.8) | |
| ≥ 50 | 831 (19.9) | 892 (10.5) | |
| Missing | 161 (3.9) | 303 (3.6) | |
| Age at diagnosis of lung cancer, y | |||
| Mean (SD) | 68.0 (8.1) | – | |
| Median (range) | 68.2 (38.1–91.0) | ||
| Time elapsed, y | |||
| Mean (SD) | 8.3 (5.4) c | 13.3 (5.1) d | |
| Median (range) | 7.3 (0–27) | 13.0 (0–28) | |
| Histological Type | |||
| Adenocarcinoma | 1182 (42.6) | ||
| Squamous cell carcinoma | 897 (32.6) | ||
| Large cell carcinoma | 221 (7.9) | ||
| Small cell carcinoma | 473 (17.1) | ||
aUnderweight (BMI < 18.5), normal weight (18.5 ≤ BMI < 25), overweight (25 ≤ BMI < 30) and obese (BMI ≥ 30)
bSubjects who had missing cigarettes smoked per day and duration of smoking
cPeriod between enrollment and diagnosis
dPeriod between enrollment and last follow-up/observation