Table 1.
Clinical characteristics of the population
| Characteristics | Cases | Controls | P |
|---|---|---|---|
| Sex | |||
| Males | 681 (70.4%) | 205 (73.7%) | 0.282 |
| Females | 286 (29.6%) | 73 (26.3%) | |
| Age (years) | 64.1 (8.8) | 59 (8.5) | <0.001 |
| BMI | 28 (6) | 28.7 (4.3) | 0.041 |
| Pack-years | 65.8 (34.8) | 34.5 (17.9) | <0.001 |
| FEV1 (%) | 47 (13.9) | 97.1 (16.1) | <0.001 |
| FVC (%) | 66.1 (16.5) | 97.5 (16.6) | <0.001 |
| FEV1/FVC (%) | 57.9 (8.5) | 78.9 (5.8) | <0.001 |
| GOLD stage | |||
| I | 13 (1.3%) | ||
| II | 370 (38%) | ||
| III | 325 (33.5%) | ||
| IV | 260 (27%) | ||
Notes: Sex and Global Initiative for Obstructive Lung Disease stage expressed in absolute numbers and percentage of the sample; the remaining values are expressed by mean and standard deviation; t-test was used for qualitative variables; Pearson’s Chi-squared test was used for qualitative variables.
Abbreviations: BMI, body mass index; FEV1, forced expiratory volume in 1 second; FVC, forced vital capacity; GOLD, Global Initiative for Obstructive Lung Disease.