Table 2.
Association between head and neck cancer and exposure to chlorinated solvents
| PCE | TCE | MC | CF | CT | At least one of these five chlorinated solvents | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Exposure | Co | Ca | ORa
[95%CI] |
Co | Ca | ORa
[95%CI] |
Co | Ca | ORa
[95%CI] |
Co | Ca | ORa
[95%CI] |
Co | Ca | ORa
[95%CI] |
Co | Ca | ORa
[95%CI] |
| Never | 2581 | 1635 | 1 | 1686 | 938 | 1 | 2432 | 1508 | 1 | 2619 | 1691 | 1 | 2622 | 1686 | 1 | 1645 | 930 | 1 |
| Ever | 89 | 70 | 1.04 [0.69 to 1.59] |
989 | 770 | 0.93 [0.77 to 1.36] |
238 | 197 | 0.91 [0.69 to 1.18] |
51 | 14 | 0.58 [0.27 to 1.26] |
48 | 19 | 0.60 [0.30 to 1.19] |
1030 | 778 | 0.91 [0.75 to 1.10] |
| Durationb | ||||||||||||||||||
| Short | 41 | 31 | 1.05 [0.56 to 1.94] |
289 | 215 | 0.86 [0.66 to 1.14] |
93 | 88 | 0.96 [0.65 to 1.43] |
21 | 7 | 0.76 [0.26 to 2.20] |
25 | 10 | 0.56 [0.22 to 1.43] |
291 | 213 | 0.87 [0.66 to1.14] |
| Intermediate | 25 | 23 | 1.27 [0.60 to 2.74] |
390 | 290 | 0.97 [0.76 to 1.24] |
66 | 46 | 0.73 [0.44 to 1.22] |
13 | 2 | 0.20 [0.03 to 1.34] |
10 | 3 | 0.36 [0.06 to 2.00] |
409 | 295 | 0.93 [0.73 to 1.19] |
| Long | 23 | 16 | 0.83 [0.37 to 1.88] |
310 | 265 | 0.95 [0.73 to 1.23] |
79 | 63 | 0.97 [0.62 to 1.52] |
17 | 5 | 0.69 [0.18 to 2.60] |
13 | 6 | 0.87 [0.25 to 2.97] |
330 | 270 | 0.93 [0.72 to 1.20] |
| p for trend | 0.88 | 0.85 | 0.67 | 0.23 | 0.38 | 0.69 | ||||||||||||
| CEI | ||||||||||||||||||
| Low | 44 | 36 | 1.15 [0.64 to 2.07] |
497 | 391 | 0.95 [0.75 to 1.19] |
114 | 107 | 1.03 [0.71 to 1.48] |
25 | 5 | 0.56 [0.16 to 1.90] |
24 | 7 | 0.44 [0.15 to 1.29] |
518 | 397 | 0.95 [0.75 to 1.19] |
| Medium | 34 | 20 | 0.65 [0.31 to 1.36] |
397 | 313 | 0.95 [0.74 to 1.21] |
100 | 63 | 0.65 [0.43 to 1.00] |
26 | 9 | 0.60 [0.22 to 1.61] |
24 | 12 | 0.74 [0.30 to 1.83] |
408 | 291 | 0.85 [0.67 to 1.10] |
| High | 11 | 14 | 1.81 [0.68 to 4.82] |
95 | 66 | 0.82 [0.54 to 1.23] |
24 | 27 | 1.42 [0.70 to 2.87] |
104 | 90 | 0.94 [0.64 to 1.38] |
||||||
| p for trend | 0.48 | 0.38 | 0.97 | 0.05 | 0.39 | 0.51 | ||||||||||||
Abbreviations PCE perchloroethylene, TCE trichloroethylene, MC methylene chloride, CF chloroform, CT carbon tetrachloride, OR odds ratio, CI confidence interval, CEI cumulative exposure index, Ca cases, Co controls
aOR adjusted for age at interview, residence area, alcohol consumption, smoking status, frequency and duration of smoking, exposure to asbestos
sbCategories of duration of exposure to solvents were defined as follows: for PCE: short: < 5, intermediate: 5–15, long: > 15; for TCE and ‘at least one of these five chlorinated solvents’: short: <5, intermediate: 5–20, long: > 20; for MC and CT short: < 5, intermediate: 5 to 15, long: > 15; for CF short: < 10, intermediate: 10 to 20, long: > 20