Table 3: Hazard ratio1 (HR) for lung cancer mortality associated with cumulative silica dust exposure.
Cumulative silica exposure (mg/m3-year) | All tungsten miners (N = 19,007) | Tungsten miners hired after 19502 (N = 17,841) | ||||
Cases | HR | 95% CI | Cases | HR | 95% CI | |
No lag Non-exposed Quartile (0.01-1.65) Quartile (1.65-3.30) Quartile (3.30-6.20) Quartile ( ≥ 6.20) 1 mg/m3-year increase In (1 mg/m3-year + 1) |
37 51 51 50 51 |
reference 0.82 1.16 1.09 0.98 1.00 1.06 |
- 0.53-1.27 0.75-1.78 0.71-1.68 0.64-1.55 0.97-1.03 0.90-1.24 |
34 44 44 43 44 |
reference 0.81 1.22 1.15 0.76 0.97 0.95 |
- 0.51-1.29 0.77-1.93 0.73-1.81 0.47-1.21 0.93-1.01 0.80-1.14 |
15-Year lag Non-exposed Quartile (0.01-1.65) Quartile (1.65-3.30) Quartile (3.30-6.20) Quartile ( ≥ 6.20) 1 mg/m3-year increase In (1 mg/m3-year + 1) |
45 58 42 48 47 |
reference 0.87 1.00 1.06 0.96 1.00 1.00 |
- 0.58-1.32 0.65-1.55 0.70-1.62 0.62-1.48 0.97-1.04 0.85-1.16 |
41 50 38 38 42 |
reference 0.86 1.15 1.05 0.78 0.98 0.90 |
- 0.56-1.33 0.72-1.82 0.66-1.66 0.49-1.23 0.94-1.02 0.76-1.07 |
25-Year lag Non-exposed Quartile (0.01-1.65) Quartile (1.65-3.30) Quartile (3.30-6.20) Quartile ( ≥ 6.20) 1 mg/m3-year increase In (1 mg/m3-year + 1) |
62 53 38 43 44 |
reference 0.88 1.17 1.21 1.23 1.02 1.14 |
- 0.58-1.32 0.76-1.82 0.79-1.85 0.80-1.90 0.98-1.05 0.97-1.35 |
58 46 35 31 39 |
reference 0.83 1.30 1.04 0.94 0.99 1.02 |
- 0.54-1.27 0.82-2.06 0.65-1.67 0.59-1.49 0.95-1.04 0.85-1.23 |
1HR was estimated by time-dependent Cox model adjusted for sex, facility, year of birth and smoking amount; 2Tungsten miners starting employment after January 1, 1950 and aged over 15 and under 45 years (quartile categories of cumulative silica dust exposure: 0.01-1.56, 1.56-2.90, 2.90-5.22, ≥ 5.22).