Table 1. Selected Baseline Characteristics of the Study Participants*.
| Characteristic | Low-Dose CT Group (N = 26,722) | Radiography Group (N = 26,732) |
|---|---|---|
| number (percent) | ||
| Age at randomization | ||
| <55 yr† | 2 (<0.1) | 4 (<0.1) |
| 55–59 yr | 11,440 (42.8) | 11,420 (42.7) |
| 60–64 yr | 8,170 (30.6) | 8,198 (30.7) |
| 65–69 yr | 4,756 (17.8) | 4,762 (17.8) |
| 70–74 yr | 2,353 (8.8) | 2,345 (8.8) |
| ≥75 yr† | 1 (<0.1) | 3 (<0.1) |
| Sex | ||
| Male | 15,770 (59.0) | 15,762 (59.0) |
| Female | 10,952 (41.0) | 10,970 (41.0) |
| Race or ethnic group‡ | ||
| White | 24,289 (90.9) | 24,260 (90.8) |
| Black | 1,195 (4.5) | 1,181 (4.4) |
| Asian | 559 (2.1) | 536 (2.0) |
| American Indian or Alaska Native | 92 (0.3) | 98 (0.4) |
| Native Hawaiian or other Pacific Islander | 91 (0.3) | 102 (0.4) |
| More than one race or ethnic group | 333 (1.2) | 346 (1.3) |
| Data missing | 163 (0.6) | 209 (0.8) |
| Hispanic ethnic group‡ | ||
| Hispanic or Latino | 479 (1.8) | 456 (1.7) |
| Neither Hispanic nor Latino | 26,079 (97.6) | 26,039 (97.4) |
| Data missing | 164 (0.6) | 237 (0.9) |
| Smoking status | ||
| Current | 12,862 (48.1) | 12,900 (48.3) |
| Former | 13,860 (51.9) | 13,832 (51.7) |
*
CT denotes computed tomography.
†
Patients in this age range were ineligible for inclusion in the screening trial but were enrolled and were included in all analyses.
‡
Race or ethnic group was self-reported.