| Cannabis only(N = 75) | Cannabis + tobacco(N = 91) | Tobacco only(N = 92) | Non-smoker(N = 81) | |
| HRCT | ||||
| Mean (SD) RA950* apical slice (%) | 10.8 (7.3) | 10.6 (7.8) | 8.3 (7.3) | 8.6 (6.1) |
| Mean (SD) RA950 mean of 3 slices (%) | 12.3 (6.7) | 10.8 (6.3) | 9.6 (6.9) | 10.5 (6.3) |
| Macroscopic emphysema, N (%) | 1 (1.3) | 15 (16.5) | 17 (18.5) | 0 (0) |
| Lung function | ||||
| Mean (SD) FEV1/FVC (%) | 76.2 (6.6) | 76.6 (7.4) | 74.7 (7.5) | 79.7 (5.4) |
| Mean (SD) FEV1 (l) | 4.17 (0.7) | 3.90 (0.9) | 3.73 (0.8) | 4.22 (0.9) |
| Mean (SD) sGaw (/s.kPa) | 1.2 (0.4) | 1.2 (0.4) | 1.3 (0.4) | 1.5 (0.5) |
| Mean (SD) TLC (l) | 7.6 (1.1) | 7.2 (1.3) | 7.2 (1.2) | 7.4 (1.3) |
| Mean (SD) RV (l) | 2.0 (0.5) | 1.9 (0.5) | 2.1 (0.6) | 2.0 (0.4) |
| Mean (SD) FRC (l) | 3.8 (0.8) | 3.8 (0.9) | 3.7 (0.8) | 3.7 (0.8) |
| Mean (SD) Tlco/Va (mmol/min/kPa/l) | 1.56 (0.2) | 1.45 (0.2) | 1.43 (0.2) | 1.57 (0.2) |
| Mean (SD) MMEF (l/min) | 213.2 (62) | 202.8 (77) | 181.2 (67) | 238.0 (73) |
| Respiratory symptoms | ||||
| Wheeze, N (%) | 20 (26.7) | 31 (34.1) | 28 (30.4) | 9 (11.1) |
| Cough, N (%) | 22 (29.3) | 26 (28.6) | 37 (40.2) | 4 (4.9) |
| Chest tightness, N (%) | 37 (49.3) | 49 (53.9) | 34 (40.0) | 28 (34.6) |
| Symptoms of chronic bronchitis, N (%) | 14 (18.7) | 28 (30.8) | 12 (13.0) | 2 (2.5) |
FEV1, forced expiratory volume in 1 s; FRC, functional residual capacity; FVC, forced vital capacity; MMEF, maximum mid-expiratory flow; RV, residual volume; sGaw, specific airways conductance; TLC, total lung capacity; Tlco/VA, carbon monoxide transfer coefficient.
*RA950, relative area of lung occupied by attenuation values lower than −950 Hounsfield units as a percentage of the total lung area.