Utrecht - Exposure to extremely low-frequency electromagnetic fields in the workplace could increase the risk of developing amyotrophic lateral sclerosis (ALS). This is what scientists from the Division of Environmental Epidemiology, Utrecht University, report in the Journal of Occupational & Environmental Medicine (2017; doi:).
ALS is neurodegenerative disease that results in progressive loss of motor nerve cells in the brain and in the Underlying spinal cord. There is currently no cure. Sick people usually die within few years of diagnosis. Previous studies had suggested that ALS could be associated with extremely low frequency electromagnetic fields, electric shocks, solvents, metals and pesticides in the workplace. However, according to the researchers, deficiencies in the study design of the previous studies called into question the relationships.
About these possible pitfalls The researchers based their study on data from the Dutch cohort study, which had examined more than 58,000 men and more than 62,000 women between 55 and 69 since 1986 for an originally different purpose. Participants who died from motor neuron disease (76 men and 60 women) were compared with around 4,000 subjects (2,411 men and 2,589 women) who were randomly selected for the purpose of the current study.
Theirs detailed employment profiles were converted into matrix of exposure to solvents, pesticides, metals and extremely low-frequency electromagnetic fields (Job Exposure Matrix). High levels of exposure to electromagnetic fields depended on the type of job and was largely restricted to men. Here the numbers ranged from two to 25 percent, while the corresponding number for women was only zero to two percent. The researchers checked the neurological health status of the patients for an average of 17 years to see if anyone among the subjects had ALS. During this time, 76 men and 60 women died of ALS.
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Particularly among the men the researchers found that exposure to extremely low-frequency electromagnetic fields in the workplace increases the risk of ALS developing. For subjects with particularly high levels of exposure through their work, the likelihood of developing ALS doubled compared to those who were never exposed to such field at work.
Other stressful factors in the workplace were only weakly associated with an increasing risk of ALS in both men and women. The team found no clear evidence of linear increase in risk as function of the amount of cumulative exposure.
On qualifying note, the scientists add that this is an observational study and cannot be used to draw firm conclusions about causality and draw effect. In summary, however, the researchers emphasize that the results of their study strengthen the assumption that ALS is associated with exposure to extremely low-frequency electromagnetic fields in the workplace.