Table 1: Characteristics of the study population.
| Cases n | 125 |
| Male/female n (%) | 110/15 (88/12) |
| Age, years | 33.8 ± 17.7 |
| Smoking never/former/current n (%) | 76/14/35 (61/11/28) |
| Initial/Recurrence n (%) | 101/24 (81/19) |
| Primary/Secondary n (%) | 103/22 (82/18) |
| Right/Left n (%) | 62/63 (50/50) |
| Outpatients/Inpatients n (%) | 32/93 (26/74) |
| Chest drainage +/- n (%) | 85/40 (68/32) |
Data are presented as mean ± SD.