| Severe COPD(n = 20) | Asymptomatic smokers(n = 14) | Never smokers(n = 13) | |
| Mean (SD) age (years) | 61 (7) | 63 (6) | 60 (10) |
| M/F | 13/7‡ | 9/5 ‡ | 1/12 |
| Mean (SD) FEV1 (% predicted) | 22 (4)†‡ | 107 (15) | 108 (17) |
| Mean (SD) FEV1/FVC | 25 (6)†‡ | 78 (6) | 80 (6) |
| RV (% predicted)§ | 255 (141) † ‡ | 104 (164) | 102 (101) |
| Tlco (% predicted)¶ | 39 (47)†‡ | 103 (79) | 93 (39) |
| Pack-years | 40 (132) | 34 (48) | 0 (0) |
| Smoking status (current/ex) | 0/20† | 6/8 | 0/0 |
| Mean (SD) BMI | 24 (3)‡ | 25 (4) | 27 (5) |
| Surgery | LVRS | TR | TR |
Values are mean (SD) for normally distributed variables and median (range) otherwise.
BMI, body mass index; COPD, chronic obstructive pulmonary disease; ex-smoker, quitting smoking for at least 6 months before the start of the study; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; LVRS, lung volume reduction surgery; pack-year, smoking 1 pack per day for 1 year; RV, residual volume; Tlco, lung carbon monoxide transfer factor; TR, tumour resection.
*Lung tissue was used for immunohistochemical analysis of leptin.
†p<0.05 vs asymptomatic smokers.
‡p<0.05 vs non-smokers.
§Values from 1 patient with COPD, 4 asymptomatic smokers and 3 never smokers are missing.
¶Values from 8 patients with COPD, 1 asymptomatic smoker and 3 never smokers are missing.