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Occupational exposure to electromagnetic fields in relation to leukemia and brain tumors: a case-control study in Sweden

Occupational exposure to low-frequency electromagnetic fields (EMF) was studied in 250 leukemia patients and 261 brain-tumor cases, diagnosed in 1983–87 and compared with a control group of 1,121 randomly selected men, from the mid-region of Sweden, 1983–87. We based the exposure assessment on measurements from 1,015 different workplaces. On the basis of the job held longest during the 10-year period before diagnosis, we found an association between the average, daily, mean level of EMF and chronic lymphocytic leukemia (CLL). The risk increased with increasing level of exposure. The odds ratios (OR) and the 95 percent confidence interval (CI) for three consecutive levels of exposure were: 1.1 (CI=0.5–2.3); 2.2 (CI=1.1–4.3); 3.0 (CI=1.6–5.8), respectively. No association was observed for acute myeloid leukemia (OR=1.0, CI=0.5–1.8; OR=0.8, CI=0.4–1.6; OR=1.0, CI=0.6–1.9). For brain tumors, the corresponding risk estimates were 1.0 (CI=0.7–1.6); 1.5 (CI=1.0–2.2); 1.4 (CI=0.9–2.1). Different EMF indices were tested. Tasks with frequent or large variations between high and low field-densities (high standard deviation) were more common among CLL subjects. For brain tumors, a prolonged high level (high median values) showed the strongest association. Confounding by place of residence, smoking, benzene, ionizing radiation, pesticides, and solvents was evaluated, and these factors did not seem to have a decisive influence on the associations. We also analyzed other potential sources of bias. For CLL, there were indications of an excess number of low-exposure subjects among non-responders, which, to some extent, may have enhanced but not caused the risk estimates obtained. Our conclusion is that the study supports the hypothesis that occupational EMF exposure is a hazard in the development of certain cancers.

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  1. 1.

    Milham S. Mortality from leukemia in workers exposed to electrical and magnetic fields. N Engl J Med 1982; 307: 249.

    Google Scholar 

  2. 2.

    McDowall ME. Leukaemia mortality in electrical workers in England and Wales. Lancet 1983; 1: 246.

    Google Scholar 

  3. 3.

    Calle EE, Savitz DA. Leukaemia in occupational groups with presumed exposure to electrical and magnetic fields. N Engl J Med 1985; 313: 1476–7.

    Google Scholar 

  4. 4.

    Gallagher RP, McBride ML, Band PR, Spinelli JJ, Threlfall WJ, Yang P. Occuptional electromagnetic field exposure, solvents exposure, and leukemia. J Occup Med 1990; 32: 64–5.

    Google Scholar 

  5. 5.

    Loomis DP, Savitz DA. Mortality from brain cancer and leukaemia among electrical workers. Br J Ind Med 1990; 47: 633–8.

    Google Scholar 

  6. 6.

    Sahl JD, Kelsh MA, Greenland S. Cohort and nested case-control studies of hematopoietic cancers and brain cancer among electric utility workers. Epidemiol 1993; 4: 104–14

    Google Scholar 

  7. 7.

    Milham S. Mortality in workers exposed to electromagnetic fields. Environ Health Perspect 1985; 62: 297–300.

    Google Scholar 

  8. 8.

    Stern FB, Waxweiller RA, Beaumont JJ, et al. A case-control study of leukemia at a naval nuclear shipyard. Am J Epidemiol 1986; 123: 980–92.

    Google Scholar 

  9. 9.

    Wright WE, Peters JM, Mack TM. Leukaemia in workers exposed to electrical and magnetic fields. Lancet 1982; ii: 1160–1

    Google Scholar 

  10. 10.

    Coleman M, Bell J, Skeet R. Leukaemia incidence in electrical workers. Lancet 1983; i: 982–3.

    Google Scholar 

  11. 11.

    Pearce N, Reif J, Fraser J. Case control studies of cancer in New Zealand electrical workers. Int J Epidemiol 1989; 18: 55–9.

    Google Scholar 

  12. 12.

    Juutilainen J, Läärä E, Pukkala E. Incidence of leukaemia and brain tumors in Finnish workers exposed to ELF magnetic fields. Int Arch Occup Environ Health 1990; 62: 289–93.

    Google Scholar 

  13. 13.

    Tynes T, Andersen A, Langmark F. Incidence of cancer in Norwegian workers potentially exposed to electromagnetic fields. Am J Epidemiol 1992; 136: 81–8.

    Google Scholar 

  14. 14.

    Guénel P, Raskmark P, Bach Andersen J, Lynge E. Cancer incidence in persons with occupational exposure to electromagnetic fields in Denmark. Br J Ind Med (in press).

  15. 15.

    Törnqvist S, Knave B, Ahlbom A, Persson T. Incidence of leukaemia and brain tumors in some “electrical occupations.” Br J Ind Med 1991; 48: 597–603.

    Google Scholar 

  16. 16.

    Lin RS, Dischinger PC, Conde J, Farrell KP. Occupational exposure to electromagnetic fields and the occurrence of brain tumors. J Occup Med 1985; 27: 413–9.

    Google Scholar 

  17. 17.

    Thomas TL, Stolley PD, Stemhagen A, et al. Brain tumor mortality risk among men with electrical jobs. A case-control study. JNCI 1987; 79: 233–8.

    Google Scholar 

  18. 18.

    Speers MA, Dobbins JG, Miller VS. Occupational exposures and brain cancer mortality: A preliminary study of east Texas residents. Am J Ind Med 1988; 13: 629–38.

    Google Scholar 

  19. 19.

    Preston-Martin S, Mack W, Henderson BE. Risk factors for gliomas and meningiomas in males in Los Angeles County. Cancer Res 1989; 49: 6137–43.

    Google Scholar 

  20. 20.

    World Health Organization. International Classification of Diseases, Seventh Revision. Geneva: WHO, 1976.

    Google Scholar 

  21. 21.

    Floderus B, Persson T, Stenlund C, et al. Occupational Exposure to Electromagnetic Fields in Relation to Leukemia and Brain Tumors. A case-control study. Solna, Sweden: National Institute of Occupational Health, PM ed 1992.

    Google Scholar 

  22. 22.

    Breslow NE, Day NE. Statistical Methods in Cancer Research. Vol 1. The Analysis of Case-control Studies. Lyon, France: International Agency for Research on Cancer, 1980; IARC Sci. Pub. No. 32.

    Google Scholar 

  23. 23.

    Matanoski GM, Elliot EA, Breysse PN. Cancer incidence in New York telephone workers. Presentation at the annual review of research on biological effects of 50 & 60 Hz electric and magnetic fields, organized by the U.S. Department of Energy and the Electric Power Research Institute, Portland, Oregon, Nov 1989.

  24. 24.

    Matanoski GM, Elliot EA, Breysse PN, Lynberg MC. Leukemia in telephone linemen. Am J Epidemiol 1993; 137: 609–19.

    Google Scholar 

  25. 25.

    Report of an Advisory Group on Non-ionising Radiation. Electromagnetic Fields and the Risk of Cancer. Documents of the NRPB, National Radiological Protection Board 1992: Vol. 3, No. 1.

  26. 26.

    Englund A, Ekman G, Zabrielski L. Occupational categories among brain tumor cases recorded in the cancer registry in Sweden. Ann N Y Acad Sci 1982; 381: 188–96.

    Google Scholar 

  27. 27.

    Office of Population Censuses and Surveys. Occupational Mortality 1979–80, 1982–83. Great Britain: HMSO, 1986; A Publication of the Government Statistical Service.

    Google Scholar 

  28. 28.

    Mack W, Preston-Martin S, Peters JM. Astrocytoma risk related to job exposure to electric and magnetic fields. Bioelectromagnetics 1991; 12: 57–66.

    Google Scholar 

  29. 29.

    Wertheimer N, Leeper E. Adult cancer related to electrical wires near the home. Int J Epidemiol 1982; 11: 345–55.

    Google Scholar 

  30. 30.

    McDowall ME. Mortality of persons resident in the vicinity of electricity transmission facilities. Br J Cancer 1986; 53: 271–9.

    Google Scholar 

  31. 31.

    Severson RK, Stevens RG, Kaune WT, et al. Acute non-lymphocytic leukemia and residential exposure to power frequency magnetic fields. Am J Epidemiol 1988; 128: 10–20.

    Google Scholar 

  32. 32.

    Coleman MP, Bell CMJ, Taylor HL, Primic-Zakelj M. Leukaemia and residence near electricity transmission equipment: A case-control study. Br J Cancer 1989; 60: 793–8.

    Google Scholar 

  33. 33.

    Youngson JHAM, Clayden AD, Myers A, Cartwright RA. A case-control study of adult haematological malignancies in relation to overhead powerlines. Br J Cancer 1991; 63: 977–85.

    Google Scholar 

  34. 34.

    Feychting M, Ahlbom A. Magnetic fields and cancer in people residing near Swedish high voltage power lines. Stockholm, Sweden: Institute of Environmental Medicin, 1992; Report No 6.

    Google Scholar 

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Additional information

Dr Floderus, Mr persson, Ms Stenlund, and Drs Wennberg and Knave are with the National Institute of Occupational Health, Solna, Sweden. Drs Floderus and Öst are affiliated also with the Karolinska Institute, Solna, Sweden. Address correspondence to Dr Floderus, Department of Neuromedicine, National Institute of Occupational Health, S-171 84 Solna, Sweden. The project is funded partially by the Swedish National Board for Industrial and Technical Development, Vattenfall, the Association of Swedish Electric Utilities, the Swedish State Railway, The Swedish National Railway Administration, The Swedish Power Association Development Foundation (VAST), the Association of Swedish Energy Distribution (REL), and the Swedish National Grid.

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Floderus, B., Persson, T., Stenlund, C. et al. Occupational exposure to electromagnetic fields in relation to leukemia and brain tumors: a case-control study in Sweden. Cancer Causes Control 4, 465–476 (1993).

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Key words

  • Acute myeloid leukemia
  • astrocytoma
  • brain tumors
  • case-control study
  • chronic lymphocytic leukemia
  • electromagnetic fields
  • leukemia
  • Sweden