Incidence rate ratios (IRR) and 95% CIs for lung cancer among 1166 ever-smoking Norwegian long-term silicon carbide (SiC) industry workers employed during 1913–2003 and followed up during 1953–2008, by tertiles of cumulative exposure, and with exposure lagging 0 and 20 years
| No lag | 20 years lag of exposure | |||||||
| Obs | IRR* | 95% CI | ptrend | Obs | IRR* | 95% CI | ptrend | |
| Total dust (mg × years/m3) | ||||||||
| 0–30 | 9 | 1.0 | 21 | 1.0 | ||||
| 30–87 | 13 | 1.0 | 0.4 to 2.4 | 12 | 1.4 | 0.7 to 3.0 | ||
| 87–900 | 36 | 1.9 | 0.9 to 4.0 | p=0.04 | 25 | 3.0 | 1.6 to 5.6 | p=0.001 |
| Respirable dust (mg × years/m3) | ||||||||
| 0–3.8 | 8 | 1.0 | 23 | 1.0 | ||||
| 3.8–10 | 18 | 1.7 | 0.7 to 4.0 | 14 | 1.6 | 0.8 to 3.2 | ||
| 10–87 | 32 | 2.0 | 0.9 to 4.4 | p=0.09 | 21 | 2.4 | 1.3 to 4.6 | p=0.007 |
| Quartz (mg × years/m3) | ||||||||
| 0–0.026 | 10 | 1.0 | 25 | 1.0 | ||||
| 0.026–0.077 | 18 | 1.3 | 0.6 to 2.8 | 16 | 1.5 | 0.8 to 2.9 | ||
| 0.077–2.3 | 30 | 1.5 | 0.7 to 3.1 | p=0.3 | 17 | 1.5 | 0.8 to 2.8 | p=0.2 |
| Cristobalite (mg × years/m3) | ||||||||
| 0–0.028 | 9 | 1.0 | 21 | 1.0 | ||||
| 0.028–0.093 | 15 | 1.2 | 0.5 to 2.7 | 18 | 2.0 | 1.0 to 3.9 | ||
| 0.093–2.7 | 34 | 2.0 | 0.9 to 4.1 | p=0.04 | 19 | 2.2 | 1.1 to 4.1 | p=0.02 |
| SiC (mg × years/m3) | ||||||||
| 0–0.83 | 14 | 1.0 | 26 | 1.0 | ||||
| 0.83–3.0 | 12 | 0.7 | 0.3 to 1.5 | 11 | 1.0 | 0.5 to 2.1 | ||
| 3.0–60 | 32 | 1.4 | 0.7 to 2.6 | p=0.2 | 21 | 2.2 | 1.2 to 4.1 | p=0.02 |
| Fibres (fibres × years/cm3) | ||||||||
| 0–0.50 | 11 | 1.0 | 21 | 1.0 | ||||
| 0.50–2.0 | 14 | 1.0 | 0.5 to 2.2 | 14 | 1.4 | 0.7 to 2.9 | ||
| 2.0–93 | 33 | 1.7 | 0.8 to 3.3 | p=0.1 | 23 | 2.3 | 1.2 to 4.4 | p=0.009 |
↵* Adjusted for age (0–54/55–74/≥75).
Obs, observed number of cases.