Mortality from Alzheimer's, motor neuron and Parkinson's disease in relation to magnetic field exposure: findings from the study of UK electricity generation and transmission workers, 1973–2004
- 1Institute of Occupational and Environmental Medicine, University of Birmingham, Edgbaston, Birmingham, UK
- 2Department of Epidemiology, University of California in Los Angeles (UCLA), Los Angeles, CA, USA
- Professor T Sorahan, Institute of Occupational and Environmental Medicine, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK;
- Accepted 25 May 2007
- Published Online First 11 July 2007
Background: There are a number of reports linking magnetic field exposure to increased risks of Alzheimer's disease and motor neuron disease.
Methods: The mortality experienced by a cohort of 83 997 employees of the former Central Electricity Generating Board of England and Wales was investigated for the period 1973–2004. All employees were employed for at least six months with some employment in the period 1973–82. Computerised work histories were available for 79 972 study subjects for the period 1971–93. Information on job and facility (location) were used to estimate exposures to magnetic fields. Two analytical approaches were used to evaluate risks, indirect standardisation (n = 83 997) and Poisson regression (n = 79 972).
Results: Based on serial mortality rates for England and Wales, deaths from Alzheimer's disease and motor neuron disease were unexceptional. There was an excess of deaths from Parkinson's disease of borderline significance. No statistically significant trends were shown for risks of any of these diseases to increase with lifetime cumulative exposure to magnetic fields (RR per 10 μT-y: Alzheimer's disease 1.10 (95% CI 0.90 to 1.33); motor neuron disease 1.06 (95% CI 0.86 to 1.32); Parkinson's disease 0.88 (95% CI 0.74 to 1.05))
Conclusions: There is no convincing evidence that UK electricity generation and transmission workers have suffered increased risks from neurodegenerative diseases as a consequence of exposure to magnetic fields.
Competing interests: None declared.
- amyotrophic lateral sclerosis
- Central Electricity Generating Board
- electromagnetic field
- standardised mortality ratio