Intermittent extremely low frequency electromagnetic fields cause DNA damage in a dose-dependent way.

Abstract

OBJECTIVES: Epidemiological studies have reported an association between exposure to extremely low frequency electromagnetic fields (ELF-EMFs) and increased risk of cancerous diseases, albeit without dose-effect relationships. The validity of such findings can be corroborated only by demonstration of dose-dependent DNA-damaging effects of ELF-EMFs in cells of human origin in vitro. METHODS: Cultured human diploid fibroblasts were exposed to intermittent ELF electromagnetic fields. DNA damage was determined by alkaline and neutral comet assay. RESULTS: ELF-EMF exposure (50 Hz, sinusoidal, 1-24 h, 20-1,000 mu T, 5 min on/10 min off) induced dose-dependent and time-dependent DNA single-strand and double-strand breaks. Effects occurred at a magnetic flux density as low as 35 mu T, being well below proposed International Commission of Non-Ionising Radiation Protection (ICNIRP) guidelines. After termination of exposure the induced comet tail factors returned to normal within 9 h. CONCLUSION: The induced DNA damage is not based on thermal effects and arouses concern about environmental threshold limit values for ELF exposure.

AI evidence extraction

Main findings

Exposure to intermittent 50 Hz ELF-EMF (20–1,000 µT; 1–24 h; 5 min on/10 min off) induced dose-dependent and time-dependent DNA single-strand and double-strand breaks in cultured human diploid fibroblasts. Effects were reported at magnetic flux density as low as 35 µT, and comet tail factors returned to normal within 9 h after exposure ended.

Outcomes measured

• DNA single-strand breaks
• DNA double-strand breaks
• Comet assay tail factors (alkaline and neutral comet assay)

Limitations

• In vitro study in cultured cells; generalizability to humans not established in abstract
• No sample size or replication details provided in abstract
• Exposure source/context (e.g., occupational vs environmental) not specified in abstract

Suggested hubs

• occupational-exposure (0.55)
  Published in an occupational/environmental health journal and discusses ELF exposure limits; specific occupational setting not described.
• who-icnirp (0.6)
  Mentions effects below proposed ICNIRP guidelines and raises concern about threshold limit values.

{
    "study_type": "in_vitro",
    "exposure": {
        "band": "ELF",
        "source": null,
        "frequency_mhz": 0.05000000000000000277555756156289135105907917022705078125,
        "sar_wkg": null,
        "duration": "1–24 h; intermittent 5 min on/10 min off"
    },
    "population": "Cultured human diploid fibroblasts",
    "sample_size": null,
    "outcomes": [
        "DNA single-strand breaks",
        "DNA double-strand breaks",
        "Comet assay tail factors (alkaline and neutral comet assay)"
    ],
    "main_findings": "Exposure to intermittent 50 Hz ELF-EMF (20–1,000 µT; 1–24 h; 5 min on/10 min off) induced dose-dependent and time-dependent DNA single-strand and double-strand breaks in cultured human diploid fibroblasts. Effects were reported at magnetic flux density as low as 35 µT, and comet tail factors returned to normal within 9 h after exposure ended.",
    "effect_direction": "harm",
    "limitations": [
        "In vitro study in cultured cells; generalizability to humans not established in abstract",
        "No sample size or replication details provided in abstract",
        "Exposure source/context (e.g., occupational vs environmental) not specified in abstract"
    ],
    "evidence_strength": "low",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "extremely low frequency",
        "ELF-EMF",
        "50 Hz",
        "intermittent exposure",
        "magnetic flux density",
        "microtesla",
        "DNA damage",
        "single-strand breaks",
        "double-strand breaks",
        "comet assay",
        "human diploid fibroblasts",
        "ICNIRP guidelines"
    ],
    "suggested_hubs": [
        {
            "slug": "occupational-exposure",
            "weight": 0.5500000000000000444089209850062616169452667236328125,
            "reason": "Published in an occupational/environmental health journal and discusses ELF exposure limits; specific occupational setting not described."
        },
        {
            "slug": "who-icnirp",
            "weight": 0.59999999999999997779553950749686919152736663818359375,
            "reason": "Mentions effects below proposed ICNIRP guidelines and raises concern about threshold limit values."
        }
    ]
}

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