Occupational asbestos exposure in cases and controls (n=960)
| Exposure* | Cases (n=494) | % | Controls (n=466) | % |
| Ever asbestos exposed | 327 | 66 | 293 | 63 |
| High-risk non-construction | 65 | 13 | 51 | 11 |
| High-risk construction | 138 | 28 | 126 | 27 |
| Medium risk industrial | 124 | 25 | 116 | 25 |
| Low risk industrial | 94 | 19 | 97 | 21 |
| Office | 73 | 15 | 76 | 16 |
| Number of patients who recalled working with asbestos (permitting a Fibre ml⁻¹ year estimate) | 22 | 25 | 107 | 23 |
| Median fibre ml⁻¹ years (IQR) | 6 (0–63) | 5 (0–60) | ||
| ≥100 fibre ml⁻¹ years | 27 | 5 | 24 | 5 |
| ≥50 fibre ml⁻¹ years | 34 | 7 | 29 | 6 |
| ≥25 fibre ml⁻¹ years | 40 | 8 | 35 | 8 |
*Categories of occupational asbestos exposure risk were defined on the basis of occupational proportional mortality ratios for mesothelioma16 and ever asbestos exposed was defined as ever having had a high or medium asbestos exposure risk job. Fibre ml⁻¹ year asbestos exposure estimates were calculated for participants who recalled working with asbestos using a source-receptor model.17 20