In this study, we examined the potential causal effect of smoking on amyotrophic lateral sclerosis (ALS) using the Project MinE data involving 12,577 patients with ALS and 23,475 controls in a Mendelian randomization (MR) framework. The MR approach has the potential to investigate a causal relationship between a risk factor and a disease, avoiding confounding and information bias that often present in conventional epidemiological studies. We found that smokers had a higher risk of ALS compared to never smokers. Our study thus provides evidence for a causal relationship between smoking and ALS. Ann Neurol 2019;85:482-484.
© 2019 American Neurological Association.