Table I.
Characteristics of LC cases and controls
| Characteristics | Pooled |
P | Central Europe |
Canada |
Norway |
Estonia |
|||||
| Cases | Controls | Cases | Controls | Cases | Controls | Cases | Controls | Cases | Controls | ||
| Total sample | 2683 | 4228 | 1841 | 2441 | 330 | 500 | 403 | 412 | 109 | 875 | |
| Males (%) | 1931 (72) | 2653 (63) | 2.6 × 10−15 | 1435 (78) | 1773 (73) | 158 (48) | 177 (35) | 251 (62) | 230 (56) | 87 (80) | 473 (54) |
| Agea, mean (SD) | 61.4 (9.6) | 55.7 (14.1) | 1.4 × 10−74 | 60.3 (8.7) | 59.6 (9.7) | 63.8 (11.5) | 52.3 (15.8) | 63.7 (10.6) | 63.2 (11.3) | 64.5 (10.3) | 43.0 (16.1) |
| Smoking status (%) | |||||||||||
| Never | 255 (9.7) | 1614 (38.8) | 137 (7.4) | 867 (35.5) | 77 (28.4) | 199 (43.6) | 27 (6.8) | 120 (31.1) | 14 (12.9) | 428 (49.0) | |
| Ever | 2366 (90.3) | 2542 (61.2) | 1704 (92.6) | 1572 (64.4) | 194 (71.6) | 258 (56.4) | 373 (93.2) | 266 (68.9) | 95 (87.1) | 446 (51.0) | |
| Former | 536 (20.5) | 1065 (25.6) | 362 (19.7) | 628 (25.8) | 94 (34.7) | 139 (30.4) | 79 (19.7) | 149 (38.6) | 1 (0.9) | 149 (17.0) | |
| Current | 1806 (68.9) | 1433 (34.5) | 1338 (72.7) | 937 (38.4) | 91 (33.6) | 86 (18.8) | 283 (70.7) | 113 (29.3) | 94 (86.2) | 297 (34.0) | |
| Unknownb | 24 (0.9) | 44 (1.1) | 4 (0.2) | 7 (0.3) | 9 (3.3) | 33 (7.2) | 11 (2.8) | 4 (1.0) | 0 (0.0) | 0 (0.0) | |
| Unavailable | 62 | 72 | 1.4 × 10−197 | 0 | 2 | 59 | 43 | 3 | 26 | 0 | 1 |
| Pack-years of smokingc, mean (SD) | 37.5 (21.2) | 24.0 (19.2) | 8.4 × 10−110 | 38.1 (19.1) | 27.4 (18.2) | 48.9 (37.0) | 25.7 (28.3) | 27.3 (16.0) | 17.4 (14.8) | 39.8 (18.0) | 13.2 (13.1) |
| Histology (%) | |||||||||||
| Adenocarcinoma | 583 (25.3) | 417 (22.6) | 90 (55.5) | 76 (25.2) | |||||||
| Squamous cell | 911 (39.6) | 781 (42.4) | 50 (30.9) | 80 (26.6) | |||||||
| Small cell | 358 (15.5) | 283 (15.4) | 22 (13.6) | 53 (17.6) | |||||||
| Mixed/Other | 452 (19.6) | 360 (19.6) | 0 (0.0) | 92 (30.6) | |||||||
| Unavailable | 379 | 0 | 168 | 102 | |||||||
na, not available; SD, standard deviation; P, P-value of test of comparison between cases and controls (t-test or chi-square test).
a
in years.
b
The ‘Unknown’ category corresponds to ever-smokers whose former or current smoking status is undetermined.
c
among ever-smokers.