Summary of characteristics for the lung cancer and resistant smokers
| Variable | Lung cancer patients (n = 446) | Healthy control smokers (n = 484) | p Value |
| Characteristic | |||
| Male | 53% | 60% | 0.007 |
| Age (years) | 69 (10) | 60 (10) | <0.001 |
| Height (cm) | 167 (0.08) | 170 (0.09) | <0.001 |
| Weight (kg) | 69 (15) | 79 (15) | <0.001 |
| History of COPD | 29% | 5% | <0.001 |
| Smoking history | |||
| Non-smokers (%) | 7% | 0 | |
| Current smoking (%) | 35% | 48% | <0.001 |
| Age started (years) | 18 (4) | 17 (3) | 0.18 |
| Years smoked | 41 (12) | 35 (11) | <0.001 |
| Pack-years | 41 (25) | 40 (19) | 0.28 |
| Cigarettes/day | 20 (10) | 24 (11) | <0.001 |
| History of other exposures | |||
| In utero smoke exposure | 18% | 17% | 0.45 |
| Mother smoked in childhood | 37% | 41% | 0.03 |
| Home ETS exposure as adult | 79% | 58% | <0.001 |
| Work ETS exposure | 86% | 63% | <0.001 |
| Work dust exposure | 63% | 47% | <0.001 |
| Work fume exposure | 41% | 38% | 0.16 |
| Asbestos exposure | 23% | 16% | 0.02 |
| Family history | |||
| COPD | 33% | 28% | 0.12 |
| Lung cancer | 19% | 9% | <0.001 |
| Lung function | |||
| FEV1 (litres) | 1.86 (0.48) | 2.86 (0.68) | <0.001 |
| FEV1 % predicted | 73% | 99% | <0.001 |
| FEV1/FVC | 64 (13) | 78 (7) | <0.001 |
| Spirometric COPD* | 51% | 0% | <0.001 |
Values are frequency (given as %) or mean (SD).
*According to GOLD 2+ criteria (FEV1/FVC < 70% and FEV1 % predicted ⩽ 80%).
COPD, chronic obstructive pulmonary disease; ETS, environmental tobacco smoke; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity.