OR between lung cancer and occupational exposure to diesel engine emissions
| Study I | Study II | Pooled studies | |||||||
| N Co | N Ca | OR* (95% CI) | N Co | N Ca | OR* (95% CI) | N Co | N Ca | OR* (95% CI) | |
| Exposure dimension | |||||||||
| Never exposed | 455 | 675 | 1.00 (ref.) | 496 | 353 | 1.00 (ref.) | 951 | 1028 | 1.00 (ref.) |
| Ever exposed | 67 | 165 | 1.48 (1.0 to 2.1) | 312 | 298 | 1.30 (1.0 to 1.7) | 379 | 463 | 1.34 (1.1 to 1.7) |
| Uncertain† exposure | 11 | 17 | 0.94 (0.4 to 2.3) | 86 | 85 | 0.91 (0.6 to 1.4) | 97 | 102 | 0.93 (0.6 to 1.3) |
| Duration (years) | |||||||||
| 1–10 | 21 | 65 | 1.90 (1.1 to 3.4) | 118 | 127 | 1.40 (1.0 to 2.0) | 139 | 192 | 1.51 (1.1 to 2.0) |
| 11–20 | 15 | 45 | 1.89 (1.0 to 3.7) | 70 | 52 | 1.04 (0.6 to 1.7) | 85 | 97 | 1.25 (0.9 to 1.8) |
| >20 | 31 | 55 | 1.01 (0.6 to 1.7) | 124 | 119 | 1.33 (0.9 to 1.9) | 155 | 174 | 1.23 (0.9 to 1.7) |
| Concentration | |||||||||
| Low | 18 | 54 | 1.49 (0.8 to 2.8) | 218 | 180 | 1.17 (0.9 to 1.6) | 236 | 234 | 1.20 (0.9 to 1.6) |
| Medium | 43 | 85 | 1.17 (0.7 to 1.8) | 84 | 104 | 1.58 (1.1 to 2.4) | 127 | 189 | 1.39 (1.0 to 1.9) |
| High | 6 | 26 | 4.62 (1.6 to 13.4) | 10 | 14 | 1.73 (0.6 to 4.7) | 16 | 40 | 2.66 (1.3 to 5.3) |
| Average time/week (h) | |||||||||
| <2 | 12 | 22 | 1.22 (0.5 to 2.8) | 18 | 18 | 1.27 (0.6 to 2.9) | 30 | 40 | 1.22 (0.7 to 2.2) |
| 2–12 | 33 | 81 | 1.53 (0.9 to 2.5) | 133 | 104 | 1.20 (0.8 to 1.7) | 166 | 185 | 1.28 (1.0 to 1.7) |
| >12 | 22 | 62 | 1.56 (0.9 to 2.8) | 161 | 176 | 1.38 (1.0 to 1.9) | 183 | 238 | 1.42 (1.1 to 1.9) |
| Cumulative exposure | |||||||||
| Non-substantial level | 44 | 97 | 1.25 (0.8 to 1.9) | 260 | 224 | 1.21 (0.9 to 1.6) | 304 | 321 | 1.21 (1.0 to 1.5) |
| Substantial level | 23 | 68 | 2.00 (1.1 to 3.6) | 52 | 74 | 1.74 (1.1 to 2.8) | 75 | 142 | 1.80 (1.3 to 2.6) |