Table 3.
Adjusted odds ratios (OR) for bladder cancer in relation to occupational exposure to diesel engine emissions from the Canadian National Enhanced Cancer Surveillance System, 1994–1997
| Diesel exposure groups | Cases | Controls | Minimala | P‐value | Fullb | P‐value | ||
|---|---|---|---|---|---|---|---|---|
| N | % | N | % | OR (95% CI) | OR (95% CI) | |||
| Ever exposed to diesel | ||||||||
| Never | 402 | 61.1 | 869 | 63.9 | 1.00 | 1.00 | ||
| Ever | 256 | 38.9 | 491 | 36.1 | 1.07 (0.88–1.31) | 0.51 | 0.88 (0.70–1.11) | 0.29 |
| Highest attained concentration of exposure to diesel | ||||||||
| Unexposed | 402 | 61.1 | 869 | 63.9 | 1.00 | 1.00 | ||
| Low | 162 | 24.6 | 377 | 27.7 | 0.88 (0.70–1.10) | 0.26 | 0.78 (0.60–1.00) | 0.05 |
| Medium | 66 | 10.0 | 89 | 6.5 | 1.46 (1.03–2.08) | 0.03 | 1.19 (0.81–1.75) | 0.37 |
| High | 28 | 4.3 | 25 | 1.8 | 2.60 (1.47–4.61) | <0.01 | 1.64 (0.87–3.08) | 0.12 |
| P trend | <0.01 | 0.49 | ||||||
| Highest attained frequency of exposure to diesel | ||||||||
| Unexposed | 402 | 61.1 | 869 | 63.9 | 1.00 | 1.00 | ||
| <5% | 20 | 3.0 | 51 | 3.8 | 0.88 (0.51–1.52) | 0.65 | 0.77 (0.44–1.36) | 0.37 |
| 5–30% | 133 | 20.2 | 270 | 19.9 | 0.97 (0.75–1.24) | 0.78 | 0.83 (0.62–1.10) | 0.19 |
| ≥30% | 103 | 15.7 | 170 | 12.5 | 1.30 (0.98–1.72) | 0.07 | 1.00 (0.74–1.37) | 0.98 |
| P trend | 0.22 | 0.57 | ||||||
| Duration of exposure to diesel | ||||||||
| Unexposed | 402 | 61.7 | 869 | 64.4 | 1.00 | 1.00 | ||
| <7 | 70 | 10.7 | 120 | 8.9 | 1.23 (0.89–1.71) | 0.21 | 1.05 (0.74–1.49) | 0.79 |
| 7–26 | 80 | 12.3 | 164 | 12.2 | 1.04 (0.77–1.40) | 0.81 | 0.80 (0.57–1.12) | 0.19 |
| ≥26 | 100 | 15.3 | 196 | 14.5 | 0.99 (0.75–1.31) | 0.93 | 0.83 (0.61–1.15) | 0.26 |
| P trend | 0.52 | 0.29 | ||||||
| Duration of exposure at low concentrations of diesel | ||||||||
| Unexposed | 453 | 69.3 | 945 | 69.9 | 1.00 | 1.00 | ||
| <6 | 54 | 8.3 | 98 | 7.3 | 1.22 (0.85–1.74) | 0.30 | 0.98 (0.67–1.43) | 0.91 |
| 6–26 | 74 | 11.3 | 143 | 10.6 | 1.01 (0.74–1.38) | 0.96 | 0.84 (0.60–1.17) | 0.31 |
| ≥26 | 73 | 11.2 | 166 | 12.3 | 0.80 (0.59–1.09) | 0.16 | 0.72 (0.51–1.01) | 0.06 |
| P trend | 0.78 | 0.12 | ||||||
| Duration of exposure at high concentrations of diesel | ||||||||
| Unexposed | 630 | 96.0 | 1335 | 98.2 | 1.00 | 1.00 | ||
| ≤10 | 11 | 1.7 | 13 | 1.0 | 2.05 (0.86–4.85) | 0.10 | 1.24 (0.52–2.94) | 0.63 |
| >10 | 15 | 2.3 | 11 | 0.8 | 2.94 (1.36–6.37) | <0.01 | 2.45 (1.04–5.74) | 0.04 |
| P trend | <0.01 | 0.07 | ||||||
| Cumulative exposure to diesel | ||||||||
| Unexposed | 402 | 61.7 | 869 | 64.4 | 1.00 | 1.00 | ||
| Lowest tertile | 69 | 10.6 | 127 | 9.4 | 1.14 (0.82–1.57) | 0.44 | 0.96 (0.68–1.36) | 0.81 |
| Middle tertile | 70 | 10.7 | 155 | 11.5 | 0.91 (0.66–1.24) | 0.55 | 0.76 (0.54–1.07) | 0.11 |
| Highest tertile | 111 | 17.0 | 198 | 14.7 | 1.15 (0.88–1.51) | 0.31 | 0.93 (0.68–1.28) | 0.66 |
| P trend | 0.50 | 0.34 | ||||||
a
Adjusted for proxy respondent, province of residence, and age at interview.
b
Adjusted for proxy respondent, province of residence, age at interview, cigarette pack‐years, cumulative asbestos, and cumulative silica exposure.