Relative risks of mortality from chronic lymphatic leukaemia, other leukaemias, all leukaemias, and all other causes by levels of estimated cumulative magnetic field exposure in subcohort with work histories (n=79 972) (eight separate analyses): study of United Kingdom electricity generation and transmission workers, 1973–97
| Cumulative magnetic field exposure (μT.y)6-151 | n | RR6-152 | (95% CI) | RR6-153 | (95% CI) |
| Chronic lymphatic leukaemia6-154: | |||||
| 0–2.4 | 21 | 1.0 | 1.0 | ||
| 2.5–4.9 | 3 | 0.64 | (0.19 to 2.17) | 0.69 | (0.20 to 2.39) |
| 5.0–9.9 | 5 | 0.59 | (0.22 to 1.57) | 0.67 | (0.24 to 1.89) |
| 10.0–19.9 | 7 | 0.92 | (0.39 to 2.18) | 1.07 | (0.41 to 2.78) |
| ⩾20.0 | 3 | 1.14 | (0.34 to 3.86) | 1.40 | (0.39 to 4.98) |
| p Value for trend6-164 | p>0.50 and >0.50 | p>0.50 and >0.50 | |||
| Other leukaemias6-161: | |||||
| 0–2.4 | 39 | 1.0 | 1.0 | ||
| 2.5–4.9 | 15 | 2.016-150 | (1.10 to 3.67) | 2.036-150 | (1.09 to 3.79) |
| 5.0–9.9 | 15 | 1.25 | (0.68 to 2.31) | 1.30 | (0.68 to 2.47) |
| 10.0–19.9 | 10 | 0.97 | (0.48 to 1.98) | 1.04 | (0.49 to 2.21) |
| ⩾20.0 | 6 | 1.52 | (0.63 to 3.64) | 1.63 | (0.66 to 4.01) |
| p Value for trend6-164 | p>0.50 and >0.50 | p=0.50 and =0.49 | |||
| All leukaemias6-162: | |||||
| 0–2.4 | 60 | 1.0 | 1.0 | ||
| 2.5–4.9 | 18 | 1.49 | (0.87 to 2.53) | 1.53 | (0.88 to 2.65) |
| 5.0–9.9 | 20 | 0.99 | (0.59 to 1.65) | 1.05 | (0.61 to 1.81) |
| 10.0–19.9 | 17 | 0.96 | (0.55 to 1.67) | 1.05 | (0.58 to 1.90) |
| ⩾20.0 | 9 | 1.37 | (0.68 to 2.79) | 1.53 | (0.73 to 3.18) |
| p Value for trend6-164 | p>0.50 and >0.50 | p>0.50 and =0.37 | |||
| All other causes6-163: | |||||
| 0–2.4 | 6,090 | 1.0 | 1.0 | ||
| 2.5–4.9 | 1,581 | 1.206-165 | (1.13 to 1.26) | 1.076-150 | (1.01 to 1.13) |
| 5.0–9.9 | 2,570 | 1.106-165 | (1.05 to 1.16) | 0.96 | (0.92 to 1.01) |
| 10.0–19.9 | 2,246 | 1.096-165 | (1.04 to 1.14) | 0.95 | (0.90 to 1.00) |
| ⩾20.0 | 701 | 0.94 | (0.87 to 1.02) | 0.886-165 | (0.81 to 0.95) |
| p Value for trend6-164 | p=0.04 (+ve) and =0.45 | p<0.001 (−ve) and <0.001 (−ve) | |||
↵6-150 p<0.05;
↵6-165 p<0.001.
↵6-151 One year refers to a working year, about 250 8 hour shifts.
↵6-152 Analysed simultaneously with sex and attained age.
↵6-153 Analysed simultaneously with sex, attained age, calendar period, year of starting employment, and negotiating body. For levels, see table 4.
↵6-164 Linearly weighted p value for trend (five exposure categories scored 1–5) and dose weighted p value for trend (five exposure categories scored 0.36, 3.67, 7.24, 13.93, 38.53), see text for details. Sign shows direction of any significant trend.