Table 2.
Mortality rate ratios and 95% confidence intervals for categories of cumulative dust exposure and cumulative chrysotile fiber exposure, by deaths from different cancer sites,a by sex (except for mesothelioma), applying 5-year lag time, adjusted for age and time since last employment
| Dust category, mg/m3-years | Men |
Women |
Fiber category, fibers/cm3-years | Men |
Women |
||||
|---|---|---|---|---|---|---|---|---|---|
| No. deaths | RR (95% CI) | No. deaths | RR (95% CI) | No. deaths | RR (95% CI) | No. deaths | RR (95% CI) | ||
| Lung cancerd | Lung cancerd | ||||||||
| 0b | 3 | 0.94 (0.30 to 3.01) | 0 | 0 | 3 | 0.82 (0.26 to 2.62) | 0 | ||
| >0 to 20 | 89 | 1.00 | 7 | 1.00 | >0 to 12 | 102 | 1.00 | 7 | 1.00 |
| ≥20 to 65 | 155 | 1.20 (0.92 to 1.57) | 11 | 0.82 (0.32 to 2.12) | ≥12 to 40 | 171 | 1.03 (0.80 to 1.32) | 11 | 0.80 (0.31 to 2.07) |
| ≥65 to 150 | 209 | 1.37 (1.04 to 1.80) | 11 | 0.63 (0.24 to 1.63) | ≥40 to 80 | 208 | 1.13 (0.87 to 1.46) | 10 | 0.67 (0.26 to 1.77) |
| ≥150 | 108 | 1.40 (1.03 to 1.90) | 12 | 1.03 (0.40 to 2.62) | ≥80 | 80 | 1.26 (0.92 to 1.72) | 13 | 1.21 (0.48 to 3.04) |
| Total | 564 | 41 | 564 | 41 | |||||
| P trend c | .02 | 1.00 | .11 | .64 | |||||
| Laryngeal cancere | Ovarian cancer | Laryngeal cancere | Ovarian cancer | ||||||
| 0 | 0 | 1 | 2.27 (0.26 to 20.12) | 0 | 0 | 1 | 2.17 (0.25 to 19.12) | ||
| >0 to 20 | 9 | 1.00 | 8 | 1.00 | >0 to 12 | 12 | 1.00 | 8 | 1.00 |
| ≥20 to 65 | 19 | 1.28 (0.57 to 2.87) | 10 | 0.78 (0.30 to 2.03) | ≥12 to 40 | 17 | 0.78 (0.37 to 1.65) | 11 | 0.80 (0.32 to 2.03) |
| ≥65 to 150 | 8 | 0.42 (0.15 to 1.14) | 11 | 0.96 (0.36 to 2.54) | ≥40 to 80 | 10 | 0.38 (0.16 to 0.92) | 10 | 0.86 (0.33 to 2.28) |
| ≥150 | 10 | 1.03 (0.39 to 2.68) | 5 | 0.72 (0.22 to 2.35) | ≥80 | 7 | 0.76 (0.29 to 2.01) | 5 | 0.62 (0.20 to 2.00) |
| Total | 46 | 35 | 46 | 35 | |||||
| P trend | .40 | .70 | .17 | .48 | |||||
| Stomach cancer | Stomach cancer | ||||||||
| 0 | 2 | 1.23 (0.29 to 5.29) | 3 | 3.10 (0.80 to 11.94) | 0 | 2 | 1.13 (0.26 to 4.84) | 3 | 2.76 (0.72 to 10.52) |
| >0 to 20 | 29 | 1.00 | 16 | 1.00 | >0 to 12 | 32 | 1.00 | 18 | 1.00 |
| ≥20 to 65 | 49 | 1.21 (0.75 to 1.94) | 23 | 0.87 (0.45 to 1.65) | ≥12 to 40 | 55 | 1.09 (0.70 to 1.71) | 21 | 0.66 (0.35 to 1.25) |
| ≥65 to 150 | 72 | 1.55 (0.96 to 2.51) | 15 | 0.54 (0.26 to 1.13) | ≥40 to 80 | 77 | 1.43 (0.91 to 2.27) | 17 | 0.58 (0.29 to 1.14) |
| ≥150 | 35 | 1.49 (0.87 to 2.57) | 14 | 0.78 (0.37 to 1.64) | ≥80 | 21 | 1.16 (0.64 to 2.08) | 12 | 0.57 (0.27 to 1.21) |
| Total | 187 | 71 | 187 | 71 | |||||
| P trend | .08 | .25 | .24 | .12 | |||||
| Colorectal cancer | Colorectal cancer | ||||||||
| 0 | 1 | 2.12 (0.27 to 16.55) | 0 | 0 | 1 | 2.20 (0.28 to 17.16) | 0 | ||
| >0 to 20 | 15 | 1.00 | 13 | 1.00 | >0 to 12 | 15 | 1.00 | 14 | 1.00 |
| ≥20 to 65 | 44 | 1.74 (0.96 to 3.15) | 24 | 1.08 (0.54 to 2.13) | ≥12 to 40 | 47 | 1.70 (0.94 to 3.06) | 26 | 1.03 (0.53 to 1.97) |
| ≥65 to 150 | 44 | 1.20 (0.65 to 2.23) | 21 | 0.80 (0.39 to 1.63) | ≥40 to 80 | 46 | 1.25 (0.68 to 2.31) | 19 | 0.75 (0.37 to 1.51) |
| ≥150 | 30 | 1.52 (0.79 to 2.91) | 19 | 1.05 (0.51 to 2.18) | ≥80 | 25 | 1.96 (1.01 to 3.82) | 18 | 0.97 (0.48 to 1.98) |
| Total | 134 | 77 | 134 | 77 | |||||
| P trend | .66 | .86 | .22 | .69 | |||||
| Mesothelioma, men and women | Mesothelioma, men and women | ||||||||
| No. deaths | RR (95% CI) | No. deaths | RR (95% CI) | ||||||
| ≥0 to 65 | 3 | 1.00 | ≥0 to 40 | 2 | 1.00 | ||||
| ≥65 to 150 | 5 | 2.54 (0.53 to 12.07) | ≥40 to 80 | 7 | 6.27 (1.10 to 35.84) | ||||
| ≥150 | 5 | 4.56 (0.94 to 22.14) | ≥80 | 4 | 7.64 (1.18 to 49.46) | ||||
| Total | 13 | 13 | |||||||
| P trend | .03 | .05 | |||||||
International Statistical Classification of Diseases and Related Health Problems codes for cancer sites are as follows: lung, C33-C34; larynx, C32; ovary, C56; stomach, C16; colon and rectum, C18-C21; mesothelioma, C45 and C38.4. CI = confidence interval; f/cm3-years = fibers/cm3-years; RR = relative risk.
Because the 5-year lag time was applied, some workers had no occupational exposure to dust or fibers; as the counting of risk time started with first exposure, they are kept as a separate group and displayed only for the purpose of completeness (see Materials and Methods).
Two-sided Ptrend across the exposure categories (ie, dust categories >0 to 20, ≥20 to 65, ≥65 to 150, and ≥150).
Without adjustment for time since last employment, the relative risk (95% CI) for lung cancer for the 3 categories of cumulative dust exposure compared with the reference category are as follows: RR = 1.07 (95% CI = 0.82 to 1.39), RR = 1.16 (95% CI = 0.90 to 1.50), and RR = 1.18 (95% CI = 0.88 to 1.58) (men) and RR = 0.83 (95% CI = 0.32 to 2.15), RR = 0.67 (95% CI = 0.26 to 1.75), and RR = 1.05 (95% CI = 0.41 to 2.69) (women); for the 3 categories of cumulative fiber exposure compared with the reference category, they are as follows: RR = 0.93 (95% CI = 0.73 to 1.19), RR = 0.99 (95% CI = 0.78 to 1.27), and RR = 1.13 (95% CI = 0.84 to 1.53) (men) and RR = 0.81 (95% CI = 0.31 to 2.08), RR = 0.70 (95% CI = 0.26 to 1.83), and RR = 1.20 (95% CI = 0.48 to 3.02) (women).
Only 1 case of laryngeal cancer in women; therefore, analysis for women was not carried out.