Exposure to electromagnetic fields does not modify neither the age of onset nor the disease progression in ALS patients.

Being exposed to electromagnetic fields has been suggested to increase the risk of developing Amyotrophic Lateral Sclerosis (ALS). Here, we investigated the effect of exposure to electromagnetic fields on ALS onset age and progression rate (ΔALSFRS-r). A large cohort of ALS patients (n = 1098) was geolocalized at the time of their diagnosis. Concomitantly, data on the distribution of power lines and repeater antennas (extremely low frequency electromagnetic fields) during the same period were retrieved. Exposure to each repeater antenna was calculated as the sum of 1/(distance from each antenna)^2. Exposure to power lines was calculated assuming each patient's address as the center of several circles of variable radius (100, 250, 500, 1000, and 2000 m). For each radius, the exposure was calculated as the length of the power lines included in the circle. Finally, patients were divided into low- and high-exposed based on the median of the exposure and compared using the Mann-Whitney test. A regression model (one for each radius) was also performed. Neither the onset age nor the ΔALSFRS-r differed among patients' low- and high-exposed to electromagnetic fields. Similarly, we could not find any significant relationship using the regression models. Our findings suggest that electromagnetic fields do not modify the ALS phenotype or progression.