Physical activity as risk factor in amyotrophic lateral sclerosis: a systematic review and meta-analysis

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder with rapid progression and high mortality. Physical activity (PA) has been identified as a major risk factor for ALS. However, the results across studies are still controversial. We aimed to explore the association between different types of PA and ALS.

The PubMed, EMBASE, Cochrane and Web of Science databases were systematically searched for case-control and cohort studies which explored the relationship between PA and ALS from inception to October 2022. The data were analyzed to generate a pooled effect and 95% confidence interval (CI).

A total of 16,686 articles were included in the systematic search. After filtering, 28 studies from online database and 6 studies from references of relevant articles remained in the analysis. Individuals with a history of vigorous physical activity (OR 1.26, 95% CI 1.06-1.49), occupational-related activity (OR 1.14, 95% CI 1.04-1.25), leisure time activity (OR 1.08, 95% CI 1.04-1.12), unclassified PA (OR 1.05 95% CI 1.02-1.09) and professional athletes (SMR 5.23, 95% CI 2.67-10.25; SIR 2.54, 95% CI 1.37-4.69) were in higher risk of developing ALS. In contrast, sport-related activity (OR 0.97, 95% CI 0.76-1.26) was not associated with ALS.

Vigorous physical activity, occupational-related activity, leisure time activity, unclassified PA and professional athletes were associated with a higher risk of ALS, while sport-related activity showed no association with ALS. Our findings clarified the relation between different types of PA and ALS and provided some practicable advice for the lifestyle of high-risk populations.