A positive causal relationship was identified between strenuous physical exercise and amyotrophic lateral sclerosis (ALS).
Why this matters
Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease thought to be caused by complex interplay between genetic and environmental factors.
Exercise has been suggested as risk for ALS, but data to date have been inconclusive. Use of Mendelian randomization (MR) counters bias and confounding variables that have limited previous analyses.