Table 1.
Cohort characteristics.
| Variable | Non-Smokers | Smoking Controls | COPD | p-Value |
|---|---|---|---|---|
| n | 12 | 56 | 47 | |
| Sex, % men | 33 | 45 | 62 | 0.104 |
| Race,% White | 50 | 73 | 87 | 7.48 × 10−3 * |
| Race, % Black | 25 | 21 | 6 | 7.48 × 10−3 * |
| Race, % Asian | 17 | 2 | 4 | 7.48 × 10−3 * |
| Race, % other | 8 | 4 | 2 | 7.48 × 10−3 * |
| Age, yr | 56 (50–60) | 58 (50–66) | 64 (58–68) | 7.95 × 10−4 * |
| Current smokers, % | 0 | 36 | 36 | 2.68 × 10−2 * |
| Pack–years | 0 (0–0) | 34 (26–44) | 42 (34–60) | 3.95 × 10−11 * |
| Body mass index | 26.21 (5.46) | 28.78 (4.47) | 28.9 (5.27) | 0.198 |
| Chronic bronchitis, % | 0 (0) | 7 (26) | 15 (36) | 0.294 |
| Exacerbations/yr | 0.08 (0.29) | 0.12 (0.43) | 0.39(0.68) | 0.117 |
| Emphysema, % | 0.15 (0.06–1.22) | 0.16 (0.05–0.4) | 1.05 (0.32–2.5) | 2.90 × 10−3 * |
| FEV1 % | 99.29 (7.31) | 100.23 (13.1) | 78.97 (19.92) | 3.87 × 10−8 * |
| FEV1/FVC | 81 (77–87) | 78 (75–81) | 61 (55–67) | 5.31 × 10−24 * |
Data are presented as median (interquartile range) or mean ± SD. * p-value < 0.05. Emphysema, %: % Emphysema voxels (<−950 Hounsfield units) in lung CT (Computed Tomography) image. Exacerbations/yr: # of exacerbations in last year. Chronic bronchitis: Daily productive cough for at least 3 months in the previous 2 consecutive years. % FEV1: Postbronchodilator % predicted forced expiratory volume in one second. FEV1/FVC: Ratio of forced expiratory volume in one second to forced vital capacity. COPD: chronic obstructive pulmonary disease.