Relative risks of mortality from brain tumours and all other causes by levels of estimated exposure to magnetic fields received in preceding 5 years (four separate analyses), study of United Kingdom electricity generation and transmission workers, 1973–94
| Exposure to magnetic field received in preceding 5 years (μT.y)4-151 | n | RR4-152 (95% CI) | RR4-153 (95% CI) |
| Brain tumours:4-154 | |||
| Zero | 86 | 1.0 | 1.0 |
| 0.01–0.49 | 17 | 0.94 (0.56 to 1.59) | 0.99 (0.58 to 1.69) |
| 0.5–1.9 | 13 | 0.95 (0.53 to 1.72) | 0.98 (0.54 to 1.81) |
| 2.0–4.9 | 6 | 0.63 (0.27 to 1.45) | 0.64 (0.28 to 1.50) |
| ⩾5.0 | 2 | 0.40 (0.10 to 1.63) | 0.42 (0.10 to 1.74) |
| RR/μT.y4-164 | 0.91 (0.81 to 1.03) | 0.92 (0.82 to 1.03) | |
| All other causes:4-161 | |||
| Zero | 7503 | 1.0 | 1.0 |
| 0.01–0.49 | 1159 | 1.04 (0.97 to 1.10) | 0.94 (0.88 to 1.00) |
| 0.5–1.9 | 668 | 0.93 (0.86 to 1.01) | 0.824-165 (0.75 to 0.89) |
| 2.0–4.9 | 374 | 0.824-165 (0.74 to 0.91) | 0.724-165 (0.65 to 0.81) |
| ⩾5.0 | 187 | 0.824-160 (0.71 to 0.95) | 0.724-165 (0.62 to 0.83) |
| RR/μT.y4-164 | 0.984-165 (0.96 to 0.99) | 0.964-165 (0.95 to 0.97) | |
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4-150 p<0.05;
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↵4-160 p<0.01;
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↵4-165 p<0.001.
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↵4-151 1 Year refers to a working year, about 250 8 hour shifts.
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↵4-152 Analysed simultaneously with sex and attained age.
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↵4-153 Analysed simultaneously with sex, attained age, calendar period, year of starting employment, and negotiating body. For levels, see table 1.
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↵4-154 Any part of death certificate coded to ICD-9 191,192, 225, 237.5, or 237.6.
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↵4-164 Five exposure categories scored by the mean value in each category—namely, 0.0, 0.19, 1.14, 3.16, and 11.40 μT.y. See text for details.
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↵4-161 No part of death certificate coded to ICD-9 191,192, 225, 237.5, or 237.6.
