Table 1. Baseline Characteristics of the Study Group.
| Parameter | Overall (N = 21,949) | NENN group (n = 9,040) | E group (n = 5,819) | N group (n = 4,737) | E + N group (n = 2,353) | P value |
|---|---|---|---|---|---|---|
| Age (years) | < 0.001 | |||||
| ≤ 59 | 8,920 (40.6) | 3,981 (44.0) | 2,243 (38.5) | 1,904 (40.2) | 792 (33.7) | |
| 60 - 64 | 6,816 (31.1) | 2,809 (31.1) | 1,819 (31.3) | 1,488 (31.4) | 700 (29.7) | |
| 65 - 69 | 4,130 (18.8) | 1,545 (17.1) | 1,149 (19.7) | 902 (19.0) | 534 (22.7) | |
| 70 - 74 | 2,083 (9.5) | 705 (7.8) | 608 (10.4) | 443 (9.4) | 327 (13.9) | |
| Sex | < 0.001 | |||||
| Women | 8,996 (41.0) | 3,764 (41.6) | 2,269 (39.0) | 2,079 (43.9) | 884 (37.6) | |
| Men | 12,953 (59.0) | 5,276 (58.4) | 3,550 (61.0) | 2,658 (56.1) | 1,469 (62.4) | |
| Race | < 0.001 | |||||
| White | 20,099 (91.6) | 8,167 (90.3) | 5,319 (91.4) | 4,407 (93.0) | 2,206 (93.8) | |
| Other | 1,850 (8.4) | 873 (9.7) | 500 (8.6) | 330 (7.0) | 147 (6.2) | |
| Education | < 0.001 | |||||
| < high school | 1,416 (7.7) | 557 (7.5) | 397 (7.9) | 279 (7.0) | 183 (9.1) | |
| Senior high school | 8,336 (45.2) | 3,230 (43.3) | 2,290 (45.8) | 1,859 (46.8) | 957 (47.6) | |
| College or above | 8,691 (47.1) | 3,672 (49.2) | 2,311 (46.2) | 1,836 (48.2) | 872 (43.3) | |
| Marital status | 0.037 | |||||
| Married/living as married | 14,741 (67.3) | 6,028 (66.9) | 3,879 (66.9) | 3,226 (68.2) | 1,608 (68.4) | |
| Widowed/divorced/separated | 6,153 (28.1) | 2,525 (28.0) | 1,677 (28.9) | 1,301 (27.5) | 650 (27.7) | |
| Never married | 995 (4.5) | 457 (5.1) | 242 (4.2) | 204 (4.3) | 92 (3.9) | |
| BMI (kg/m2) | < 0.001 | |||||
| < 25 | 7,322 (33.5) | 2,518 (28.0) | 2,358 (40.6) | 1,404 (29.7) | 1,042 (33.5) | |
| 25 - 29.9 | 8,864 (40.5) | 3,724 (41.4) | 2,319 (39.9) | 1,909 (40.4) | 912 (38.9) | |
| ≥ 30 | 5,688 (26.0) | 2,760 (30.7) | 1,129 (19.4) | 1,411 (29.9) | 388 (16.6) | |
| Smoking status | < 0.001 | |||||
| Former smoking | 11,246 (51.2) | 5,020 (55.5) | 2,643 (45.4) | 2,572 (54.3) | 1,011 (43.0) | |
| Current smoking | 10,703 (48.8) | 4,020 (44.5) | 3,176 (54.6) | 2,165 (45.7) | 1,342 (57.0) | |
| Smoking, pack-years | < 0.001 | |||||
| 30 - 59 | 14,352 (65.4) | 6,276 (69.4) | 3,476 (59.7) | 3,222 (68.0) | 1,378 (58.6) | |
| 60 - 89 | 5,494 (25.0) | 2,034 (22.5) | 1,668 (28.7) | 1,102 (23.3) | 690 (29.3) | |
| ≥ 90 | 2,103 (9.6) | 730 (8.1) | 675 (11.6) | 413 (8.7) | 285 (12.1) | |
| Family history of lung cancer | 0.047 | |||||
| No | 17,607 (80.2) | 7,312 (80.9) | 4,623 (79.4) | 3,817 (80.6) | 1,855 (78.8) | |
| Yes | 4,342 (19.8) | 1,728 (19.1) | 1,196 (20.6) | 920 (19.4) | 498 (21.2) |
P values from the χ2 test. BMI: body mass index; NENN group: non-emphysema and non-nodules; E group: emphysema without nodules; N group: nodules without emphysema; E + N group: nodules with emphysema.