Exposure to extremely low frequency magnetic fields and electric shocks and working in “electrical occupations” have been studied since the 1980s as potential occupational risk factors for amyotrophic lateral sclerosis development. It has been suggested that exposure to electric shocks in these electrical occupations rather than exposure to extremely low frequency magnetic fields may be the causal factor for the development of amyotrophic lateral sclerosis. In occupational settings, it is difficult to separate exposure scenarios for electric shocks and extremely low frequency magnetic fields because they often occur together, making an independent assessment of the effects of the two exposures challenging. Electroconvulsive therapy, a common treatment for some psychiatric conditions, presents a setting where a well‐documented exposure occurs in a medical setting without substantial exposure to extremely low frequency magnetic fields. This provides a unique opportunity to examine the potential role of electric shocks in amyotrophic lateral sclerosis development in a controlled and well‐documented clinical environment without the confounding effect of extremely low frequency magnetic fields.
|Reference group 1||electroconvulsive therapy treatments: no|
|Group 2||electroconvulsive therapy treatments: yes|
|Reference group 3||number of electroconvulsive therapy treatments: 0|
|Group 4||number of electroconvulsive therapy treatments: 1 - 10|
|Group 5||number of electroconvulsive therapy treatments: > 11|
A total of 7,936 subjects (0.6%) of the cohort received electroconvulsive therapy. Overall, 1,246 subjects (0.1%) of the cohort were diagnosed with amyotrophic lateral sclerosis.
A moderately increased, statically non-significant hazard ratio (HR) for amyotrophic lateral sclerosis following electroconvulsive therapy was observed (HR 1.39; CI 0.69–2.80). A statistically significant increase in the hazard ratio of amyotrophic lateral sclerosis was observed among those who received more than 10 electroconvulsive therapy treatments (HR 2.24; CI 1.00–5.01) compared to those receiving no electroconvulsive therapy, with an even stronger association observed among subjects older than 65 years (HR 3.03; CI 1.13–8.10).
The authors concluded that the results provide weak support for the hypothesis that receipt of electroconvulsive therapy increases the risk of developing amyotrophic lateral sclerosis.