Table 1. Demographic description of the dataset.
| Institutions | Total | P-value | |||
|---|---|---|---|---|---|
| B | G | K | |||
| (n = 1,694) | (n = 1,858) | (n = 2,335) | (n = 5,887) | ||
| Sex, men | 996 (58.8) | 1,458 (78.5) | 1,875 (80.3) | 4,329 (73.5) | <0.001 |
| Age (years) | 56±11 | 53±11 | 54±13 | 54±11 | <0.001 |
| Non-smoker | 876 (51.7) | 621 (33.4) | 742 (31.9) | 2239 (38.1) | <0.001 |
| Ex-smoker | 415 (24.5) | 431 (23.2) | 576 (24.8) | 1422 (24.2) | |
| Current smoker | 403 (23.8) | 805 (43.3) | 1007 (43.3) | 2215 (37.7) | |
| High risk of lung cancer† | 129 (8.0) | 350 (19.4) | 314 (13.5) | 793 (13.8) | <0.001 |
| Average risk of lung cancer | 1,485 (92.0) | 1,450 (80.6) | 2,009 (86.5) | 4,944 (86.2) | |
Note: Except where indicated, data are mean (± SD) or number (%). SD = standard deviation missing data for pack-year information (n = 150, 2.5%). Comparisons of means and proportions between institutions for demographic information were performed using analysis of variance (ANOVA) and chi-squared tests.
†High-risk lung cancer indicates age 55–74 years with a smoking history of 30 pack-years or more