Association between occupational exposure to power frequency electromagnetic fields and amyotrophic lateral sclerosis: a review.
BACKGROUND
For the past two decades, there has been concern over electromagnetic exposure and human health. While most research has focused on cancer and reproductive outcomes, there is interest in the relationship between electromagnetic fields (EMF) and neurodegenerative diseases.


METHODS
We review epidemiological findings and evidence regarding the association between occupational exposure to power frequency EMFs and amyotrophic lateral sclerosis (ALS). Medline was searched for citations related to occupational hazards and ALS, literature reviews and epidemiological evaluations.


RESULTS
Nine out of the ten epidemiological studies that have been conducted on the risk of ALS in relation to occupational exposure to EMF show moderate to strong relative risk estimates that supported a link between them. Although data from these studies was consistent, the causal inference to a link between EMF exposure and ALS is restricted mainly due to the lack of direct information on EMF exposure and incomplete consideration of the other potential risk factors for ALS at workplaces. For instance, electric shock, in particular, is more common in electrical occupations than in any other occupations.


CONCLUSIONS
This review concludes that further studies should consider investigating the separate effect of EMF exposure and electrical shocks to make more specific interpretations. On-site measurements of EMF should be conducted to include information on EMF exposure from residences as well as workplaces to improve exposure assessment.
Li
Chung-Yi
CY
Department of Public Health, College of Medicine, Fu-Jen Catholic University, Hsinchuang, Taipei Hsien, Taiwan Republic of China. chungyi@mails.fju.edu.tw
Sung
Fung-Chang
FC
D000690:Amyotrophic Lateral Sclerosis / Q000453:epidemiology*; D015982:Bias; D016022:Case-Control Studies; D015331:Cohort Studies; D015986:Confounding Factors, Epidemiologic; D004574:Electromagnetic Fields / Q000009:adverse effects*; D006801:Humans; D016273:Occupational Exposure / Q000009:adverse effects*; D018570:Risk Assessment