Carcinogenicity of intermediate frequency magnetic field in mice

2019 · No effect · Moderate evidence

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No effectModerate evidencePaper 1894

Study snapshot

Publicationmanual · 2019

Study typeanimal

Reported directionNo effect

Evidence ratingModerate

Abstract

Carcinogenicity of intermediate frequency magnetic field in mice Nishimura I, Doi Y, Imai N, Kawabe M, Mera Y, Shiina T. Carcinogenicity of intermediate frequency magnetic field in Tg.rasH2 mice. Bioelectromagnetics. 2019 Mar 15. doi: 10.1002/bem.22177. Abstract Although the likelihood of exposure to leaking intermediate frequency magnetic fields (MFs) from electronic devices, such as induction-heating and wireless power transfer systems, has increased, biological data assessing the health risks associated with human exposure remain insufficient. We examined the carcinogenicity of a 20 kHz MF, a typical frequency produced by induction-heating cookers, using a transgenic rasH2 mouse model. Twenty-five male and female CByB6F1-Tg(HRAS)2Jic mice were exposed to a 0.20 mT, 20 kHz MF (22 h/day) or sham-exposed for 26 weeks. As a positive control, 10 male and female rasH2 mice from the same batch were administered a single intraperitoneal injection of 75 mg/kg N-methyl-N-nitrosourea. A blinded histopathological evaluation was performed, and the same experiments were conducted twice, independently, to confirm the reproducibility of the results. Histopathological examination revealed that spontaneous neoplastic lesions, such as splenic hemangiosarcomas and gastric squamous cell papillomas, were less (1-3 per group) in the MF- and sham-exposed groups. The frequency of the neoplastic lesions was not significantly different between the groups. Eight to ten mice in each positive-control group exhibited malignant lymphoma. The outcomes were consistent between duplicated experiments, which indicates lack of carcinogenicity of 20 kHz MF in the rasH2 mouse model ncbi.nlm.nih.gov

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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 typeanimal

Effect directionno_effect

PopulationTransgenic rasH2 mice (CByB6F1-Tg(HRAS)2Jic), male and female

Sample size60

Exposureintermediate frequency · 0.02 MHz · 22 h/day for 26 weeks

Evidence strengthModerateConfidence: 78% · Peer reviewed: yes

Main findings

rasH2 mice exposed to a 0.20 mT, 20 kHz magnetic field for 26 weeks had low numbers of spontaneous neoplastic lesions (1–3 per group), and the frequency of neoplastic lesions was not significantly different from sham-exposed mice. Positive-control mice given N-methyl-N-nitrosourea showed malignant lymphoma in 8–10 mice per group. Results were consistent across two independent duplicate experiments.

Outcomes measured

Carcinogenicity / neoplastic lesions (histopathology)
Splenic hemangiosarcoma
Gastric squamous cell papilloma
Malignant lymphoma (positive control)

Limitations

Animal model (transgenic rasH2 mice); generalizability to humans not established in abstract
Exposure described as 0.20 mT at 20 kHz; limited to this frequency/intensity and exposure schedule
Sample size per exposure/sham group not fully clear from abstract (numbers given but group allocation details not fully specified)

View raw extracted JSON

{
  "study_type": "animal",
  "exposure": {
    "band": "intermediate frequency",
    "source": "induction-heating cooker / wireless power transfer (leaking magnetic fields)",
    "frequency_mhz": 0.02,
    "sar_wkg": null,
    "duration": "22 h/day for 26 weeks"
  },
  "population": "Transgenic rasH2 mice (CByB6F1-Tg(HRAS)2Jic), male and female",
  "sample_size": 60,
  "outcomes": [
    "Carcinogenicity / neoplastic lesions (histopathology)",
    "Splenic hemangiosarcoma",
    "Gastric squamous cell papilloma",
    "Malignant lymphoma (positive control)"
  ],
  "main_findings": "rasH2 mice exposed to a 0.20 mT, 20 kHz magnetic field for 26 weeks had low numbers of spontaneous neoplastic lesions (1–3 per group), and the frequency of neoplastic lesions was not significantly different from sham-exposed mice. Positive-control mice given N-methyl-N-nitrosourea showed malignant lymphoma in 8–10 mice per group. Results were consistent across two independent duplicate experiments.",
  "effect_direction": "no_effect",
  "limitations": [
    "Animal model (transgenic rasH2 mice); generalizability to humans not established in abstract",
    "Exposure described as 0.20 mT at 20 kHz; limited to this frequency/intensity and exposure schedule",
    "Sample size per exposure/sham group not fully clear from abstract (numbers given but group allocation details not fully specified)"
  ],
  "evidence_strength": "moderate",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "intermediate frequency",
    "magnetic field",
    "20 kHz",
    "0.20 mT",
    "induction-heating cooker",
    "wireless power transfer",
    "rasH2",
    "mouse",
    "carcinogenicity",
    "histopathology",
    "sham exposure",
    "N-methyl-N-nitrosourea"
  ],
  "suggested_hubs": [
    {
      "slug": "wireless-power-transfer",
      "weight": 0.6,
      "reason": "Mentions wireless power transfer systems as a source of intermediate-frequency magnetic fields."
    },
    {
      "slug": "induction-cooking",
      "weight": 0.7,
      "reason": "Exposure frequency described as typical of induction-heating cookers (20 kHz)."
    }
  ]
}

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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: 10.1002/bem.22177
PubMed: Not supplied

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