Estimated hazard ratio (HR) and excess absolute risk (EAR) for a mean ‘daily weighted average’ (DWA) exposure at the National Institute for Occupational Safety and Health recommended exposure limit of 0.5 μg/m3, and mean DWA exposure associated with 10−3 EAR, under different assumed exposure–response models
| Exposure–response model* | Estimated HR (95% CI) at 0.5 μg/m3 | EAR at 0.5 μg/m3 | Mean DWA exposure for 10−3 EAR (μg/m3) |
| Best monotonic PWL†—all workers | 1.68 (1.16 to 2.54) | 0.045 | 0.014 |
| Best monotonic PWL†—excluding professional and asbestos workers | 1.26 (0.77 to 2.20) | 0.017 | 0.033 |
| Best categorical—all workers | 1.39 (1.10 to 1.75)‡ 1.11 (1.04 to 1.19)§ | 0.025 0.0073 | 0.023 0.070 |
| Best categorical—excluding professional and asbestos workers | 1.11 (0.81 to 1.55)‡ 1.09 (1.01 to 1.19)§ | 0.0071 0.0061 | 0.073 0.082 |
| Power—all workers | 1.45 (1.22 to 1.73) | 0.030 | 0.0050 |
| Power—excluding professional and asbestos workers | 1.74 (1.31 to 2.31) | 0.049 | 0.0035 |
↵* All models adjust for birth cohort and plant.
↵† Best monotonic piecewise log-linear (PWL) indicates best-fitting model producing a monotonic exposure–response within the 0–2 μg/m3 region. It includes cutpoints at 1.0, 10 and 50 μg/m3.
↵‡ Best categorical includes cutpoints at 0.6, 2, 8, 12 and 50 μg/m3 and uses the HR estimate at 0.6–2.0 μg/m3.
↵§ Best categorical includes same cutpoints but uses the HR estimate at 2.0–8 μg/m3.