Characteristics of cases and referents by company
| Company | Cases | Referents | |
|---|---|---|---|
| A | Total (n) | 27 | 51 |
| Male (n (%)) | 24 (89) | 45 (88) | |
| Mean age at symptom onset (y)2-150 | 34.5 | 35.6 | |
| Median months employed (n)2-150 | 30 | 30 | |
| Smoked at time of employment (n (%)) | 16 (59) | 23 (45) | |
| Smoked at symptom onset (n (%))2-150 | 11 (41) | 14 (27) | |
| Mean cigarettes/day at start of employment (n) | 16.4 | 16.8 | |
| History of hay fever (n (%)) | 5 (19) | 4 (8) | |
| History of eczema (n (%)) | 3 (11) | 3 (6) | |
| History of asthma (n (%)) | 1 (4) | 1 (2) | |
| History of hay fever, eczema or asthma (n (%)) | 8 (30) | 5 (10) | |
| B | Total (n) | 7 | 12 |
| Male (n) | 7 | 12 | |
| Mean age at diagnosis of 1st case (y)2-151 | 46.8 | 51.6 | |
| Median months employed (n)2-151 | 48.2 | 97.2 | |
| Smoked at time of employment (n (%))2-152 | 5 (71) | 8 (73) | |
| Smoked at symptom onset (n (%))2-151 2-152 | 5 (71) | 5 (45) | |
| Mean cigarettes/day at employment (n)2-152 | 16.3 | 15.4 | |
| History of hay fever | 0 | 0 | |
| History of eczema | 0 | 0 | |
| History of asthma | 1 | 0 |