Mean (SD) characteristics of the COPD cohorts and resistant smokers
| Parameter | COPD(N = 230) | Resistant smokers(N = 210) | Differences(p value) |
|---|---|---|---|
| *There were also no significant differences in the age started smoking, age stopped smoking, or duration of smoking. | |||
| †After correcting for age there was no difference in the pack years. | |||
| % men | 59% | 63% | 0.88 |
| Age (years) | 65 (10) | 59 (13) | <0.001 |
| Pack years | 50 (29) | 42 (25) | 0.002† |
| Cigarettes/day | 24 (15) | 24 (12) | 0.76* |
| FEV1 (l) | 1.6 (0.56) | 2.9 (0.73) | 0.01 |
| FEV1 (% predicted) | 42 (18) | 96% (10) | <0.001 |
| FEV1/FVC | 51 (15) | 82 (8) | <0.001 |