Baseline characteristics, smoking status, and lung function stratified by sex and spirometric results
| Variable | Total | Normal spirometry | Airway obstruction | ||
|---|---|---|---|---|---|
| Men | Women | Men | Women | ||
| Values are mean (SD) unless otherwise indicated. | |||||
| FEV1, forced expiratory volume in 1 second; FVC, forced vital capacity; FTND, Fagerström test for nicotine dependence. | |||||
| N (%) | 3077 (100%) | 1192 (38.7%) | 859 (27.9%) | 675 (21.9%) | 351 (11.4%) |
| Age (years) | 52.1 (10.5) | 50.1 (11.1) | 50.0 (8.9) | 56.8 (9.9) | 55.0 (9.6) |
| Age of smoking initiation (years) | 19.8 (4.9) | 18.9 (4.4) | 21.1 (5.1) | 18.7 (4.0) | 21.6 (5.9) |
| Cigarettes per day | 18.9 (8.3) | 19.8 (8.7) | 16.9 (6.9) | 20.0 (8.8) | 18.8 (7.9) |
| Pack-years | 30.0 (17.0) | 30.4 (17.2) | 23.9 (12.5) | 37.0 (16.6) | 31.0 (15.6) |
| FEV1/FVC (%) | 74.2 (12.9) | 81.1 (7.4) | 81.9 (7.3) | 59.2 (9.3) | 60.1 (7.5) |
| FEV1 (l) | 2.70 (0.9) | 3.46 (0.8) | 2.45 (0.5) | 2.2 (0.8) | 1.69 (0.6) |
| FEV1 (% predicted) | 88.5 (22.8) | 97.2 (17.8) | 96.5 (17.5) | 66.1 (20.2) | 69.0 (19.9) |
| FTND (points) | 4.76 (2.5) | 4.85 (2.4) | 4.44 (2.5) | 4.93 (2.4) | 4.99 (2.4) |
| No. of previous cessation attempts | 1.69 (3.5) | 1.78 (4.4) | 1.80 (3.0) | 1.47 (2.5) | 1.37 (2.1) |