Abstract

Overview

Exposure to extremely low frequency magnetic fields (ELF-MF) and electric shocks is common in many occupations, yet it is unclear if such exposures are linked to Amyotrophic lateral sclerosis (ALS). This systematic review and meta-analysis investigates whether occupational exposure to ELF-MF and/or electric shocks contributes to ALS risk.

Methodology

• Extensive database search: PubMed, Embase, and Web of Science until the end of 2019.
• Meta-analysis with random-effects model used to calculate pooled risk estimates.
• Assessment of study heterogeneity and publication bias.

Findings

A weak yet significant association was found between occupational exposure to ELF-MF and increased risk of ALS:

• Pooled Relative Risk (RR): 1.20 (95% Confidence Interval: 1.05, 1.38)
• Heterogeneity: Moderate to high (I2=66.3%)
• Publication Bias: Present (Egger's test=0.03)

No significant association was observed between electric shocks and ALS:

• RR: 0.97 (95% CI: 0.80, 1.17)
• Heterogeneity: High (I2=80.5%)
• Publication Bias: Minimal (Egger's test=0.24)

Conclusion

Occupational exposure to ELF-MF may be a contributing factor to ALS. However, results must be approached with caution due to heterogeneity and publication bias.