ORIGINAL ARTICLE

Occupational exposure to low frequency magnetic fields and dementia: a case–control study

Andreas Seidler¹, Petra Geller², Albert Nienhaus³, Tanja Bernhardt⁴, Ingeburg Ruppe¹, Siegfried Eggert¹, Maila Hietanen⁵, Timo Kauppinen⁵, Lutz Frölich⁴

¹ Federal Institute for Occupational Safety and Health (BAuA), Berlin, Germany
² Institute of Occupational Medicine, Johann Wolfgang Goethe-University, Frankfurt/Main, Germany
³ Institution for Statutory Accident Insurance and Prevention in the Health and Welfare Services, Hamburg, Germany
⁴ Department for Gerontopsychiatry, Central Institute of Mental Health, Mannheim, Germany
⁵ Department of Epidemiology and Biostatistics, Finnish Institute of Occupational Health, Helsinki, Finland

Correspondence to:
Dr A Seidler
Federal Institute for Occupational Safety and Health (BAuA), Nöldnerstr. 40-42, D-10317 Berlin, Germany; seidler.andreas{at}baua.bund.de

Background: Several studies point to a potential aetiological relevance to dementia of exposure to low-frequency magnetic fields, but the evidence is inconclusive.

Objective: To further examine the relationship between low frequency magnetic fields and dementia.

Methods: From 23 general practices, 195 patients with dementia were recruited. Of these, 108 had possible Alzheimer’s disease, 59 had possible vascular dementia and 28 had secondary or unclassified dementia. A total of 229 controls were recruited: 122 population controls and 107 ambulatory patients free from dementia. Data were gathered in a structured personal interview; in cases, the interview was administered to the next of kin. Exposure to low-frequency electromagnetic fields was assessed by expert rating. To identify occupations suspected to be associated with dementia, major occupations were a priori formed. Odds ratios were calculated using logistic regression, to control for age, region, sex, dementia in parents and smoking.

Results: Exposure to magnetic fields was not significantly associated with dementia; restriction of the analysis to cases with possible Alzheimer’s disease or possible vascular dementia did not lead to statistically significant results. We found an increased risk of dementia in blue-collar occupations (electrical and electronics workers, metal workers, construction workers, food and beverage processors and labourers).

Conclusions: Our study does not support a strong association between occupational exposure to low-frequency magnetic fields and dementia. Further studies should consider the relationship between blue-collar work and the late development of dementia.

Abbreviations: BAuA, German Federal Institute for Occupational Safety and Health; MMSE, Mini-Mental State Examination

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