Amyotrophic lateral sclerosis, occupational exposure to extremely low frequency magnetic fields and electric shocks: a systematic review and meta-analysis

Reviews on environmental health · 2020 · Mixed · Low evidence

← Research stream

MixedLow evidencePaper 2165

Study snapshot

PublicationReviews on environmental health · 2020

Study typemeta_analysis

Reported directionMixed

Evidence ratingLow

Abstract

Amyotrophic lateral sclerosis, occupational exposure to extremely low frequency magnetic fields and electric shocks: a systematic review and meta-analysis Hamed Jalilian, Kamran Najafi, Yahya Khosravi, Martin Röösli. Amyotrophic lateral sclerosis, occupational exposure to extremely low frequency magnetic fields and electric shocks: a systematic review and meta-analysis. Rev Environ Health. 2020 Sep 18;/j/reveh.ahead-of-print/reveh-2020-0041/reveh-2020-0041.xml. doi: 10.1515/reveh-2020-0041. Abstract Exposure to extremely low frequency magnetic fields (ELF-MF) and electric shocks occurs in many workplaces and occupations but it is unclear whether any of these exposures cause Amyotrophic lateral sclerosis (ALS). The aim of this systematic review and meta-analysis is to explore whether occupational exposure to ELF-MF and/or electric shocks are risk factor for ALS. We searched PubMed, Embase, and Web of Science databases up to the end of 2019. Pooled risk estimates were calculated using random-effects meta-analysis including exploration of the sources of heterogeneity between studies and publication bias. Twenty-seven publications fulfilled the inclusion criteria. We found a weak, significant, association between occupational exposure to ELF-MF and the risk of ALS (RRPooled estimate: 1.20; 95%CI: 1.05, 1.38) with moderate to high heterogeneity (I2=66.3%) and indication of publication bias (PEgger's test=0.03). No association was observed between occupational exposure to electric shocks and risk of ALS (RRPooled estimate: 0.97; 95%CI: 0.80, 1.17) with high heterogeneity (I2=80.5%), and little indication for publication bias (PEgger's test=0.24). The findings indicate that occupational exposure to ELF-MF, but not electric shocks, might be a risk factor for ALS. However, given the moderate to high heterogeneity and potential publication bias, the results should be interpreted with caution. pubmed.ncbi.nlm.nih.gov

Machine Enhanced Logic

AI evidence extraction

Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.

Study typemeta_analysis

Effect directionmixed

PopulationNot supplied

Sample size27

ExposureELF

Evidence strengthLowConfidence: 78% · Peer reviewed: yes

Main findings

Across 27 included publications, occupational exposure to extremely low frequency magnetic fields (ELF-MF) was associated with a weak but statistically significant increased risk of ALS (pooled RR 1.20; 95% CI 1.05–1.38), with moderate to high heterogeneity (I2=66.3%) and indication of publication bias (Egger’s test p=0.03). Occupational exposure to electric shocks was not associated with ALS risk (pooled RR 0.97; 95% CI 0.80–1.17), with high heterogeneity (I2=80.5%) and little indication of publication bias (Egger’s test p=0.24).

Outcomes measured

Amyotrophic lateral sclerosis (ALS) risk

Limitations

Moderate to high heterogeneity across included studies (I2=66.3% for ELF-MF; I2=80.5% for electric shocks).
Indication of publication bias for ELF-MF analysis (Egger’s test p=0.03).
Authors note results should be interpreted with caution.

View raw extracted JSON

{
  "study_type": "meta_analysis",
  "exposure": {
    "band": "ELF",
    "source": "occupational",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": null
  },
  "population": null,
  "sample_size": 27,
  "outcomes": [
    "Amyotrophic lateral sclerosis (ALS) risk"
  ],
  "main_findings": "Across 27 included publications, occupational exposure to extremely low frequency magnetic fields (ELF-MF) was associated with a weak but statistically significant increased risk of ALS (pooled RR 1.20; 95% CI 1.05–1.38), with moderate to high heterogeneity (I2=66.3%) and indication of publication bias (Egger’s test p=0.03). Occupational exposure to electric shocks was not associated with ALS risk (pooled RR 0.97; 95% CI 0.80–1.17), with high heterogeneity (I2=80.5%) and little indication of publication bias (Egger’s test p=0.24).",
  "effect_direction": "mixed",
  "limitations": [
    "Moderate to high heterogeneity across included studies (I2=66.3% for ELF-MF; I2=80.5% for electric shocks).",
    "Indication of publication bias for ELF-MF analysis (Egger’s test p=0.03).",
    "Authors note results should be interpreted with caution."
  ],
  "evidence_strength": "low",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "amyotrophic lateral sclerosis",
    "ALS",
    "occupational exposure",
    "extremely low frequency magnetic fields",
    "ELF-MF",
    "electric shocks",
    "systematic review",
    "meta-analysis",
    "heterogeneity",
    "publication bias"
  ],
  "suggested_hubs": [
    {
      "slug": "occupational-exposure",
      "weight": 0.95,
      "reason": "Focuses on workplace/occupational exposure to ELF magnetic fields and electric shocks in relation to ALS."
    }
  ]
}

AI can be wrong. Always verify against the paper.

AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: 10.1515/reveh-2020-0041
PubMed: 32946420

Read the original paper →

Related papers

← Back to the Research Library