Mortality from neurodegenerative disease and exposure to extremely low-frequency magnetic fields: 31 years of observations on Swiss railway employees.
OBJECTIVE
The objective of the present study was to investigate the relationship between extremely low-frequency magnetic field (ELF-MF) exposure and mortality from several neurodegenerative conditions in Swiss railway employees.


METHODS
We studied a cohort of 20,141 Swiss railway employees with 464,129 person-years of follow-up between 1972 and 2002. For each individual, cumulative exposure was calculated from on-site measurements and modelling of past exposure. We compared cause-specific mortality in highly exposed train drivers (mean exposure: 21 microT) with less exposed occupational groups (for example station masters: 1 microT).


RESULTS
The hazard ratio for train drivers compared to station masters was 1.96 [95% confidence interval (CI) = 0.98-3.92] for senile dementia and 3.15 (95% CI = 0.90-11.04) for Alzheimer's disease. For every 10 microT years of cumulative exposure senile dementia mortality increased by 5.7% (95% CI = 1.3-10.4), Alzheimer's disease by 9.4% (95% CI = 2.7-16.4) and amyotrophic lateral sclerosis by 2.1% (95% CI = -6.8 to 11.7). There was no evidence for an increase in mortality from Parkinson's disease and multiple sclerosis.


CONCLUSIONS
This study suggests a link between exposure to ELF-MF and Alzheimer's disease and indicates that ELF-MF might act in later stages of the disease process.
Röösli
Martin
M
Department of Social and Preventive Medicine, University of Berne, Berne, Switzerland. Roeoesli@ispm.unibe.ch
Lörtscher
Manfred
M
Egger
Matthias
M
Pfluger
Dominik
D
Schreier
Nadja
N
Lörtscher
Emanuel
E
Locher
Peter
P
Spoerri
Adrian
A
Minder
Christoph
C
D015331:Cohort Studies; D004574:Electromagnetic Fields / Q000009:adverse effects*; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D019636:Neurodegenerative Diseases / Q000209:etiology / Q000401:mortality*; D009784:Occupational Diseases / Q000209:etiology / Q000401:mortality*; D016273:Occupational Exposure / Q000009:adverse effects*; D011890:Railroads; D013557:Switzerland / Q000453:epidemiology