Smoking and clinical stage: Stockholm workshop scale
Smoking | Stage 0–1 Minimal symptoms | Stage II Moderate symptoms | Stage III Severe symptoms | |
Non-smoker | 86 | 85 | 113 | 284 |
Smoker | 74 | 134 | 109 | 317 |
Total | 160 | 219 | 222 | 601 |
Smokers (%) | 46.3 | 61.2 | 49.1 | 52.8 |
p=0.007 by χ2 teat.