Characteristics of non-participating and participating patients (n=430).
| Non-participants | Participants | ||
|---|---|---|---|
| Visit 1 (1962–70) | Visit 1 (1962–70) | Visit 2 (1991–8) | |
| BHR=bronchial hyperresponsiveness; FEV1=forced expiratory volume in 1 second. | |||
| *p<0.05 non-participants v participants. | |||
| n | 202 | 228 | 228 |
| Median (range) time to follow up (years) | – | – | 26 (21–33) |
| Median (range) age (years) | 28 (13–44) | 23 (13–44)* | 49.5 (35–74) |
| Sex (% male) | 62.4 | 57.9 | – |
| Median (range) age of onset of asthma (years) | 4 (0–42) | 4 (0–39) | – |
| Median (range) untreated period (years) | 11 (0–40) | 14 (0–42) | – |
| Smoking (%) | 52.5 | 36.8* | 26.8 |
| ≥1 positive skin test (%) | 86.1 | 94.3* | 82.5 |
| Geometric mean (SD) IgE (IU) | No data | No data | 87.3 (4.1) |
| Geometric mean (SD) slope BHR | 6.2 (3.4) | 7.1 (3.4) | 3.9 (4.7) |
| BHR ≤32 mg/ml (%) | 100 | 100 | 84.3 |
| BHR ≤4 mg/ml (%) | 50.5 | 55.7 | 52.0 |
| Mean (SD) prebronchodilator FEV1 (% pred) | 62.1 (23.1) | 62.8 (23.1) | 71.1 (23.5) |
| Mean (SD) postbronchodilator FEV1 (% pred) | 85.4 (22.2) | 88.0 (20.6) | 83.6 (22.2) |
| Mean (SD) FEV1 reversibility (% pred) | 23.3 (11.0) | 25.2 (12.9) | 12.5 (7.5) |
| FEV1 reversibility ≥9% predicted (%) | 96.0 | 95.2 | 63.1 |