| Parameter | CT group(n = 2052) | Control group(n = 2052) | p Value |
| Gender, M/F (n) | 1147/905 | 1120/932 | 0.40 |
| Mean (range) age (years) | 57.9 (49–71) | 57.8 (49–71) | 0.75 |
| Mean (SD) pack years | 36.4 (13.4) | 35.9 (13.4) | 0.23 |
| Smoking status: current/ex (n) | 1545/507 | 1579/473 | 0.21 |
| Mean (SD) FEV1 | 2.9 (0.75) | 2.9 (0.76) | 0.82 |
| Mean (SD) FEV1 (% predicted) | 93.4 (16.9) | 94.3 (17.4) | 0.09 |
FEV1, forced expiratory volume in 1 s.