Characteristics of current smokers and ex-smokers with COPD
| Current smokers | Ex-smokers(combined group) | Ex-smokers(quit <3.5 years) | Ex-smokers(quit ⩾3.5 years) | |
|---|---|---|---|---|
| Data are presented as mean (SD) or median (IQR: 25–75th percentile). | ||||
| Ex-smokers are divided into two groups based on median duration of smoking cessation (3.5 years). | ||||
| FEV1, forced expiratory volume in 1 second, IVC, inspiratory vital capacity, ΔFEV1, reversibility to salbutamol (change in FEV1 as percentage of predicted), Kco, carbon monoxide transfer coefficient. | ||||
| *p<0.05 compared with COPD current smokers (χ2 tests for sex differences, two tailed unpaired t tests for other (log transformed) data). | ||||
| †p<0.05 compared with COPD ex-smokers who quit <3.5 years (two tailed unpaired t tests). | ||||
| Sex (M/F, n) | 59/13 | 40/2* | 20/1 | 20/1 |
| Age (years) | 60 (8) | 64 (7)* | 61 (8) | 67 (4)*† |
| Pack years (years) | 43 (32–56) | 37 (28–53) | 45 (29–65) | 35 (26–41)* |
| Duration of smoking cessation (years) | – | 3.5 (1–10) | 1.0 (1.0–2.0) | 10 (6.5–14.5) |
| Smoking duration (years) | 44 (8) | 41 (10) | 43 (11) | 39 (8) |
| Chronic bronchitis (%) | 55.6 | 31.0* | 23.8* | 38.1 |
| Lung function | ||||
| Post-bronchodilator FEV1 (% pred) | 63.3 (8.3) | 62.5 (9.6) | 62.6 (10) | 62.5 (9.4) |
| Post-bronchodilator FEV1/IVC (%) | 49.5 (8.5) | 46.0 (8.3)* | 45.3 (8.6)* | 46.7 (8.1) |
| ΔFEV1 (% pred) | 6.9 (5.2) | 6.8 (4.5) | 6.9 (3.9) | 6.8 (5.1) |
| Kco (% pred) | 73.3 (25.1) | 80.4 (25.9) | 75.3 (24.9) | 85.7 (26.5)* |