Table 2. Subgroup analyses of the association between TCDD and cancer incidence and mortality.
| Categories | Classification | Study number | No. of cases | RR or SMR (95% CI) | Heterogeneity |
Study | |
|---|---|---|---|---|---|---|---|
| I2 | p | ||||||
| Exposure incidence | |||||||
| cancer type | breast cancer | 3 | 3768 | 0.99(0.93–1.06) | 9.30% | 0.356 | |
| Hodgkin’s lymphoma | 2 | 49 | 1.13(0.83–1.54) | — | — | Read20 | |
| 26 | 1.42(0.93–2.18) | — | — | Pesatori25 | |||
| lymphatic leukemia | 2 | 104 | 1.35(0.93–1.97) | — | — | Read20 | |
| 13 | 0.83(0.46–1.48) | — | — | Pesatori25 | |||
| non-Hodgkin’s lymphoma | 4 | 4263 | 1.09(0.92–1.30) | 65.80% | 0.001 | ||
| soft-tissue sarcoma | 4 | 105 | 1.37(0.97–1.93) | 48.70% | 0.041 | ||
| Exposure mortality | |||||||
| cancer type | buccal cavity and pharynx | 2 | 22 | 1.30(0.82–1.97) | — | — | Kogevinas15 |
| 11 | 2.17(1.08–3.87)* | — | — | Manuwald29 | |||
| esophagus | 3 | 44 | 1.52(1.09–2.13)* | 9.10% | 0.333 | ||
| stomach | 7 | 433 | 1.02(0.82–1.27) | 68.10% | 0.001 | ||
| colorectal | 7 | 453 | 1.05(0.94–1.19) | 20.10% | 0.214 | ||
| colon | 5 | 298 | 0.97(0.86–1.09) | 0.00% | 0.532 | ||
| rectum | 5 | 154 | 1.18(0.97–1.44) | 25.10% | 0.238 | ||
| liver and biliary | 5 | 212 | 1.01(0.79–1.30) | 0.00% | 0.046 | ||
| pancreas | 4 | 139 | 0.93(0.78–1.11) | 0.00% | 0.719 | ||
| peritoneum | 2 | 5 | 2.19(0.45–6.41) | — | — | Steenland16 | |
| 3 | 1.23(0.40–2.80) | — | — | Kogevinas15 | |||
| larynx | 4 | 45 | 2.20(1.61–3.02)* | 0.00% | 0.563 | ||
| trachea/lung | 8 | 1190 | 1.21(0.89–1.65) | 95.20% | <0.001 | ||
| prostate | 5 | 172 | 1.14(0.97–1.34) | 0.00% | 0.830 | ||
| kidney | 4 | 90 | 1.39(1.08–1.78)* | 16.60% | 0.309 | ||
| bladder | 5 | 117 | 1.73(0.95–3.18) | 89.00% | <0.001 | ||
| Hodgkin’s disease | 4 | 43 | 1.35(0.97–1.88) | 0.00% | 0.895 | ||
| non-Hodgkin’s lymphoma | 6 | 239 | 1.18(1.01–1.37)* | 20.10% | 0.235 | ||
| myeloma | 3 | 50 | 1.49(1.03–2.15)* | 24.80% | 0.256 | ||
| leukemia | 5 | 156 | 1.14(0.96–1.35) | 0.00% | 0.464 | ||
| skin | 2 | 9 | 0.89(0.36–2.18) | — | — | Kogevinas15 | |
| 3 | 0.85(0.49–1.48) | — | — | Consonni21 | |||
| brain nervous system | 3 | 57 | 0.91(0.69–1.20) | 0.00% | 0.418 | ||
| bone | 2 | 2 | 5.00(0.60–18.1) | — | — | Collins12 | |
| 3 | 1.08(0.22–3.14) | — | — | Kogevinas15 | |||
| soft-tissue sarcoma | 6 | 46 | 1.60(1.15–2.23)* | 0.00% | 0.550 | ||
| breast | 4 | 234 | 1.27(0.78–2.06) | 87.80% | <0.001 | ||
| endometrium and uterus | 2 | 3 | 3.41(0.70–9.96) | — | — | Kogevinas15 | |
| 43 | 0.99(0.44–2.24) | — | — | Consonni21 | |||
| exposure way | non-occupational | 2 | 803 | 1.28(0.65–2.52) | — | — | Revich17 |
| 4235 | 1.00(0.97–1.04) | — | — | Read20 | |||
| occupational | 5 | 1667 | 1.25(1.07–1.46)* | 78.30% | 0.001 | ||
| industrial accident | 3 | 2405 | 1.02(0.91–1.14) | 44.80% | 0.093 | ||
| Vietnam war | 1 | 12 | 0.70(0.30–1.10) | — | — | Michalek10 | |
| Serum mortality | |||||||
| cancer type | digestive organs | 4 | 82 | 1.22(0.88–1.69) | 44.00% | 0.147 | |
| respiratory system | 3 | 82 | 1.25(0.86–1.81) | 57.50% | 0.095 | ||
| lung | 4 | 74 | 0.99(0.86–1.15) | 0.00% | 0.450 | ||
| prostate | 2 | 4 | 1.40(0.40–3.60) | — | — | Collins23 | |
| 14 | 1.08(0.79–1.49) | — | — | Boers27 | |||
| non-Hodgkin’s lymphoma | 2 | 4 | 4.50(1.20–11.50)* | — | — | Collins23 | |
| 7 | 1.36(1.06–1.74)* | — | — | Boers27 | |||
| exposure way | non-occupational | 1 | 72 | 2.34(1.08–5.08)* | — | — | Lin28 |
| occupational | 4 | 925 | 1.43(1.23–1.66)* | 0.00% | 0.442 | ||
| reference category | external | 5 | 733 | 1.39(1.18–1.63)* | 0.00% | 0.458 | |
| internal | 2 | 192 | 1.80(1.16–2.82)* | — | — | Boers27 | |
| 72 | 2.34(1.08–5.08)* | — | — | Lin28 | |||
— Could not be calculated.
*Significant association was indicated, statistical z test: p < 0.05.