Smoking and amyotrophic lateral sclerosis: A mendelian randomization study.

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.