Personal characteristics at baseline by doctor diagnosed asthma status (N=5817)
| Characteristic | No asthma diagnosis N=5209 | Asthma* N=608 | Asthma plus† N=50 | Asthma only‡ N=558 |
| Age | ||||
| Mean (SD) | 54.3 (12.3) | 52.3 (13.2) | 60.1 (11.4) | 51.7 (13.1) |
| Missing=58 | ||||
| Gender | ||||
| Male (n, %) | 5043, 98% | 586, 97% | 48, 98% | 538, 97% |
| Missing=59 | ||||
| Smoking status (n, %) | ||||
| Current | 442, 9% | 38, 7% | 9, 19% | 29, 6% |
| Ex-smoker | 1285, 27% | 171, 31% | 19, 40.5% | 152, 30% |
| Never-smoker | 3017, 64% | 349, 62% | 19, 40.5% | 330, 64% |
| Missing=515 | ||||
| Pack years§ | ||||
| Mean (SD) | 16.2 (18.2) | 14.9 (19.1) | 27.6 (32.6) | 13.0 (15.3) |
| Median (IQR) | 10 (3.5–22.5) | 10 (3–20) | 18.8 (5–37.5) | 10 (3–18) |
| Missing=563 | ||||
| Family history of asthma (n, %) | ||||
| Yes | 681, 13% | 233, 38% | 19, 38% | 214, 38% |
| No | 4528, 87% | 375, 62% | 31, 62% | 344, 62% |
| Missing=0 | ||||
*All individuals with doctor diagnosed asthma
†Individuals with doctor diagnosed asthma plus at least one other self-reported respiratory diagnosis within the group of COPD, chronic bronchitis and hypersensitivity pneumonitis (HP)
‡Only the stipulated diagnosis of asthma, excluding all other self-reported respiratory diagnoses within the group of COPD, chronic bronchitis and HP
§Pack-years = (number of cigarettes smoked a day/20) multiplied by the number of years smoked; for those who smoke(d)
COPD, chronic obstructive pulmonary disease; N or n, count.