| Subjects n | 587 |
| Age yrs | 60.2±5.4 |
| Height m | 1.78±0.07 |
| BMI kg·m−2 | 26.9±3.6 |
| Observation time yrs median (IQR) | 2.9 (2.8–3.0) |
| Smoking exposure pack-yrs | 41.2±18.7 |
| Current smokers | 304 (49.9) |
| FEV1 L | 3.36±0.73 |
| FEV1 % pred | 97.7±18.1 |
| FVC L | 4.96±0.82 |
| FVC % pred | 107.2±15.1 |
| FEV1/FVC % | 71.6±9.0 |
| FEV1/FVC <70% | 218 (35.8) |
| FEV1/FVC <LLN | 106 (17.9) |
| Total lung emphysema severity# HU | -908.5±20.9 |
Data are presented as mean±sd or n (%), unless otherwise stated. BMI: body mass index; IQR: interquartile range; FEV1: forced expiratory volume in 1 s; % pred: % predicted; FVC: forced vital capacity; LLN: lower limit of normal. #: expressed as Perc15, the Hounsfield unit point below which 15% of the low-attenuation areas voxels are distributed (the lower the Perc15 values are, i.e. the closer to -1,000 HU, the more emphysema is present).