Patient characteristics
| Patients n | 40 |
| Sex M:F | 17:23 |
| Age mean (range) | 42.3 (20–59) |
| Smoking | |
| Neversmokers n | 20 |
| Exsmokers# n | 8 |
| Current smokers n (pack-yrs) | 12 (0.8–40.5) |
| Atopy¶ no:yes | 25:15 |
| Specific IgE no:yes:not tested | 29:10:6 |
| B-eosinophil count 109·L−1 mean (range) | 0.195 (0.011–0.700) |
| Previous asthma diagnosis no:yes | 13:27 |
| Previous asthma medication no:yes | 13:27 |
| PEF surveillance at work done no:yes | 17:23 |
| Complies with OA | 8 of 23 |
| Does not comply with OA | 5 of 23 |
| Different | 10 of 23 |
| Baseline FEV1 | |
| L mean (range) | 3.39 (2.17–4.79) |
| % pred mean (range) | 94 (64–121) |
| Histamine provocation test done no:yes | 11:35 |
| PD15FEV1 ≥mg+ | 19 of 35 |
| PD15FEV1 >1.6 mg+ | 16 of 35 |
| Protective medication during challenge no:yes | 48:2§ |
| Challenge test result | |
| Bronchoconstriction no:yes | 36:14 |
M: male
F: female
Ig: immunoglobulin
OA: occupational asthma
FEV1: forced expiratory volume in one second
PD15FEV1: dose of inhaled histamine causing a 15% fall in FEV1
#: stopped smoking at least 1 yr before the examination
¶: defined as one or more positive (≥3 mm) reactions in the standard skin-prick test series
+: 14
§: patients 12 and 31