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).