Neurodegenerative diseases in welders and other workers exposed to high levels of magnetic fields.
BACKGROUND
Previous work has suggested an increase in risk of amyotrophic lateral sclerosis (ALS) and Alzheimer's disease among workers exposed to extremely low-frequency magnetic fields (ELF-MF). We evaluated the relation between ELF-MF from occupational exposures and mortality from neurodegenerative diseases.


METHODS
The study was based on a cohort of Swedish engineering industry workers, comprising 537,692 men and 180,529 women. The cohort was matched against the 3 most recent censuses and The Causes of Death Registry. Levels of ELF-MF exposure were obtained by linking occupation according to the censuses to a job exposure matrix. We used 4 levels of exposure and considered both the primary and contributing causes of death, 1985-96.


RESULTS
The risk of Alzheimer's disease as primary or contributing cause of death increased with increasing exposure to ELF-MF among both men and women, with a relative risk (RR) of 4.0 and a 95% confidence interval (95% CI) of 1.4-11.7 in the highest exposure group for both sexes combined. There was a RR of 2.2 (95% CI: 1.0-4.7) for ALS in the highest exposure group with the suggestion of an exposure-response relationship. No evidence of increased risk was seen for Parkinson's disease or multiple sclerosis.


CONCLUSIONS
The findings support previous observations of an increased risk of Alzheimer's disease and ALS among employees occupationally exposed to ELF-MF. Further studies based on morbidity data are warranted.
Håkansson
Niclas
N
Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden. niclas.hakansson@imm.ki.se
Gustavsson
Per
P
Johansen
Christoffer
C
Floderus
Birgitta
B
D000328:Adult; D000368:Aged; D000544:Alzheimer Disease / Q000209:etiology* / Q000401:mortality*; D000690:Amyotrophic Lateral Sclerosis / Q000209:etiology* / Q000401:mortality*; D002423:Cause of Death; D015331:Cohort Studies; D004574:Electromagnetic Fields / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D008669:Metallurgy; D008875:Middle Aged; D016273:Occupational Exposure; D012042:Registries / Q000706:statistics & numerical data*