[Evaluation of genotoxic and/or co-genotoxic effects in cells exposed in vitro to extremely-low frequency electromagnetic fields].

Annali di igiene : medicina preventiva e di comunita · 2004 · Mixed · Low evidence

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MixedLow evidencePaper 5208

Study snapshot

PublicationAnnali di igiene : medicina preventiva e di comunita · 2004

Study typein_vitro

Reported directionMixed

Evidence ratingLow

Abstract

During the last two decades, concerns have arisen regarding a possible association between extremely-low frequency (ELF) electromagnetic fields (EMF) exposure and cancer incidence (e.g. childhood acute leukaemia, cancer of the nervous system, and lymphomas). In 1979, Wertheimer and Leeper firstly reported an excess of cancer mortality among children living in homes located near power lines and presumably exposed to elevated magnetic fields. Subsequently, a large number of epidemiological studies investigated the possible association between residential or occupational exposure to ELF-EMF and cancer. Several in vivo and in vitro models have been investigated with the effort to determine a link, if any, between such fields and mutagenesis and to determine the possible mechanism of cancer risk. However, a causal relationship between exposure to ELF-EMF and cancer has been suggested but has not been unequivocally demonstrated. In 1998, following an analysis of the results retrieved in the literature, the U.S. National Institute of Environmental Health Sciences proposed to apply a "possible human carcinogen" category (Group 2B) to ELF-EMF. More recently, in 2002, the same classification for ELF-MF was proposed by the International Agency for Research on Cancer. In this in vitro approach, to test the genotoxic and/or co-genotoxic potency of ELF-MF, we used the alkaline single-cell microgel-electrophoresis (comet) assay and the cytokinesis block micronucleus test. Co-exposure assays were performed in the presence of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), 4-nitroquinoline N-oxide (4NQO), benzene, 1,4-benzenediol (1,4-BD), or 1,2,4-benzenetriol (1,2,4-BT). An ELF-MF (50 Hz, 5 mT) was obtained by a system composed of capsulated induction coils. ELF-MF alone was unable to cause direct primary DNA damage. Whereas, an increased extent of DNA damage was observed in cells co-exposed to ELF-MF and MNNG, 1,4-BD, or 1,2,4-BT. An opposite trend was observed in cells treated with 4NQO and co-exposed to ELF-MF. Moreover, the frequency of micronucleated cells in ELF-MF-exposed cells was higher than in control cultures. Our findings suggest that the tested ELF-MF (50 Hz, 5 mT) possess genotoxic (micronucleus test) and co-genotoxic (comet assay) capabilities. The possibility that ELF-MF might interfere with the genotoxic activity of xenobiotics has important implications, since human populations are likely to be exposed to a variety of genotoxic agents concomitantly with exposure to this type of physical agent.

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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 typein_vitro

Effect directionmixed

PopulationNot supplied

Sample sizeNot supplied

ExposureELF

Evidence strengthLowConfidence: 78% · Peer reviewed: yes

Main findings

Cells exposed to an ELF magnetic field (50 Hz, 5 mT) showed no direct primary DNA damage by comet assay when exposed to ELF-MF alone. Increased DNA damage was reported in co-exposures with ELF-MF plus MNNG, 1,4-benzenediol, or 1,2,4-benzenetriol, while an opposite trend was observed with 4NQO plus ELF-MF. The frequency of micronucleated cells was higher in ELF-MF-exposed cells than in controls.

Outcomes measured

Primary DNA damage (comet assay)
Micronucleus frequency (cytokinesis-block micronucleus test)
Co-genotoxic interactions with chemical agents (MNNG, 4NQO, benzene metabolites)

Limitations

Cell type(s) not specified in the abstract
Exposure duration and timing not reported
In vitro findings may not generalize to in vivo or human exposures
Co-exposure effects differed by chemical agent (direction not consistent across agents)

View raw extracted JSON

{
  "study_type": "in_vitro",
  "exposure": {
    "band": "ELF",
    "source": "other",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": null
  },
  "population": null,
  "sample_size": null,
  "outcomes": [
    "Primary DNA damage (comet assay)",
    "Micronucleus frequency (cytokinesis-block micronucleus test)",
    "Co-genotoxic interactions with chemical agents (MNNG, 4NQO, benzene metabolites)"
  ],
  "main_findings": "Cells exposed to an ELF magnetic field (50 Hz, 5 mT) showed no direct primary DNA damage by comet assay when exposed to ELF-MF alone. Increased DNA damage was reported in co-exposures with ELF-MF plus MNNG, 1,4-benzenediol, or 1,2,4-benzenetriol, while an opposite trend was observed with 4NQO plus ELF-MF. The frequency of micronucleated cells was higher in ELF-MF-exposed cells than in controls.",
  "effect_direction": "mixed",
  "limitations": [
    "Cell type(s) not specified in the abstract",
    "Exposure duration and timing not reported",
    "In vitro findings may not generalize to in vivo or human exposures",
    "Co-exposure effects differed by chemical agent (direction not consistent across agents)"
  ],
  "evidence_strength": "low",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "extremely-low frequency",
    "ELF",
    "electromagnetic fields",
    "magnetic field",
    "50 Hz",
    "5 mT",
    "genotoxicity",
    "co-genotoxicity",
    "comet assay",
    "micronucleus test",
    "MNNG",
    "4NQO",
    "benzene metabolites"
  ],
  "suggested_hubs": [
    {
      "slug": "occupational-exposure",
      "weight": 0.2,
      "reason": "Abstract discusses occupational/residential ELF-EMF context, though the reported work is in vitro."
    }
  ]
}

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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: Not supplied
PubMed: 15554538

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