Table 2.
Characteristics of study participants by alternative COPD measures.
| Variable | Lung Cancer Cases | Controls | Test of Homogeneity |
|---|---|---|---|
| Self-reported emphysema (n, %)1 | |||
| No | 256 (82.8) | 677 (91.2) | <0.001 |
| Yes | 53 (17.2) | 66 (8.9) | |
| Self-reported COPD (n, %)1 | |||
| No | 211 (67.8) | 572 (77.2) | 0.002 |
| Yes | 100 (32.2) | 169 (22.8) | |
| Emphysema on CT scan (n,%) | |||
| No | 109 (36.9) | 382 (52.6) | <0.001 |
| Yes | 186 (63.1) | 344 (47.4) | |
| GOLD COPD severity (n, %) | |||
| 0 (none) | 157 (49.5) | 505 (67.7) | <0.001 |
| 1 (mild) | 20 (6.3) | 37 (5.0) | |
| 2 (moderate) | 88 (27.8) | 133 (17.8) | |
| 3 (severe) | 43 (13.6) | 63 (8.4) | |
| 4 (very severe) | 9 (2.8) | 8 (1.1) | |
| Emphysema on qCT (median, IQR)2 | 1.8 (3.8) | 1.1 (2.6) | <0.001 |
| Air trapping on qCT (median, SD)3 | 23.5 (19.7) | 16.6 (17.3) | <0.001 |
| Emphysema on qCT2 (threshold value of 4.8%) | |||
| No | 220 (76.4) | 606 (84.6) | 0.002 |
| Yes | 68 (23.6) | 110 (15.4) | |
| Air trapping on qCT3 (threshold value of 19.5%) | |||
| No | 151 (52.4) | 493 (68.7) | <0.001 |
| Yes | 137 (47.6) | 225 (31.3) | |
1
Self-report of emphysema and COPD (including reports of COPD, chronic bronchitis and/or emphysema) at least one year prior to diagnosis/interview.
2
Percent of total lung voxels < -950 HU in inspiration across both lungs.
3
Percent of total lung voxels < -856 HU in expiration across both lungs.