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Malignant lymphoma and occupational exposure to extremely low frequency magnetic fields and electrical shocks: a nested case-control study in a cohort of four Nordic countries
  1. Hamed Jalilian1,
  2. Mònica Guxens2,3,4,5,
  3. Sanna Heikkinen6,
  4. Eero Pukkala6,7,
  5. Anke Huss8,
  6. Seyed Kamal Eshagh Hossaini9,
  7. Kristina Kjærheim10,
  8. Roel Vermeulen8
  1. 1Department of Occupational Health Engineering, Research Center for Environmental Pollutants, Faculty of Health, Qom University of Medical Sciences, Qom, Iran (the Islamic Republic of)
  2. 2ISGlobal, Barcelona, Spain
  3. 3Pompeu Fabra University, Barcelona, Spain
  4. 4Spanish Consortium for Research on Epidemiology and Public Health (CIBERESP), Instituto de Salud Carlos III, Madrid, Spain
  5. 5Department of Child and Adolescent Psychiatry, Erasmus MC, University Medical Centre, Rotterdam, The Netherlands
  6. 6Finnish Cancer Registry, Institute for Statistical and Epidemiological Cancer Research, Helsinki, Finland
  7. 7Faculty of Social Sciences, Tampere University, Tampere, Finland
  8. 8Institute for Risk Assessment Sciences, University of Utrecht, The Netherlands, Utrecht, The Netherlands
  9. 9Department of Pediatrics, School of Medicine, Hazrat-e Fateme Masoume Hospital, Qom, Iran (the Islamic Republic of)
  10. 10Department of Research, Cancer Registry of Norway, Oslo, Norway
  1. Correspondence to Mr Hamed Jalilian; jalilianh{at}


Background Exposure to extremely low frequency magnetic fields (ELF-MFs) and electric shocks is a common occupational risk factor in many workplaces. Recent investigations have highlighted a possible association between such exposures and lymphoma risk. This study was carried out to further explore the association between occupational exposure to ELF-MFs and electric shocks and risk of lymphoma in a large Nordic census-based cohort.

Methods We included cases of non-Hodgkin's lymphoma (NHL, n=68 978), chronic lymphocytic leukaemia (CLL, n=20 615) and multiple myeloma (MM, n=35 467) diagnosed between 1961 and 2005 in Finland, Iceland, Norway and Sweden. Cases were matched to five controls by year of birth, sex and country. Lifetime occupational ELF-MF and electric shock exposures were assigned to jobs reported in population censuses using job-exposure matrices. The risk of cancer was assessed based on cumulative exposure to ELF-MF and electric shocks. ORs with 95% CIs were estimated using logistic models adjusted for occupational co-exposures relevant to lymphomas.

Results Less than 7% of the cases experienced high levels of ELF-MF. We observed no increased risks among workers exposed to high levels of ELF-MF for NHL (OR: 0.93; CI 0.90 to 0.97), CLL (OR: 0.98; CI 0.92 to 1.05) or MM (OR: 0.96; CI 0.90 to 1.01).

Conclusion Our results do not provide support for an association between occupational exposure to ELF-MFs and electric shocks and lymphoma risk.

  • electromagnetic fields
  • radiation, nonionizing
  • leukemia
  • occupational health

Data availability statement

All data relevant to the study are included in the article or uploaded as supplementary information.

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Data availability statement

All data relevant to the study are included in the article or uploaded as supplementary information.

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  • Contributors MG, AH and RV planned the study. SH, EP and KK contributed to data collection. HJ prepared the first draft of the manuscript. RV is responsible for the overall content as the guarantor. All authors interpreted the data, critically revised the manuscript and approved of the final version to be published.

  • Funding This work was supported by Qom University of Medical Sciences (grant number:1096) and by ZonMw (grant number 85500026). MG is funded by a Miguel Servet II fellowship (CPII18/00018) awarded by the Spanish Institute of Health Carlos III. The authors acknowledge support from the Spanish Ministry of Science and Innovation and the State Research Agency through the “Centro de Excelencia Severo Ochoa 2019-2023” Program (CEX2018-000806-S), and support from the Generalitat de Catalunya through the CERCA Program. The Nordic Occupational Cancer (NOCCA) Study was funded by the Nordic Cancer Union.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.