Effect of exposure to extremely low frequency magnetic fields on melatonin levels in calves is seasonally dependent

Scientific Reports · 2015 · Mixed · Moderate evidence

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MixedModerate evidencePaper 2721

Exposure to 50 Hz extremely low frequency magnetic fields inhibited melatonin secretion in calves during winter, but increased melatonin concentration in summer. The inhibitory effect in winter was stronger than the positive effect in summer.

Study snapshot

PublicationScientific Reports · 2015

Study typerandomized_trial

Reported directionMixed

Evidence ratingModerate

Abstract

Abstract The question of health effects of extremely low frequency (50/60 Hz) magnetic fields (ELFMF) has been widely discussed, but the mechanisms of interaction of these fields with biological systems for intensities relevant to human and animal exposure are still under question. The melatonin (MLT) hypothesis suggests that exposure to ELFMF might decrease MLT production thereby promoting cancerogenesis. So far, most studies of MLT secretion under exposure to ELFMF reported negative or inconsistent results. Here, we measured salivary MLT in 1–2 months old cattle calves exposed to 50 Hz-MF in the hundreds of nT-range. We found an inhibitory effect of the ELFMF upon MLT secretion in winter (in accordance with the MLT hypothesis). In contrast, in summer, MLT concentration was increased by ELFMF exposure (contrary to the MLT hypothesis). The inhibitory effect in winter was much stronger than the positive effect in summer. We hypothesize that this season-dependent effect upon MLT synthesis might by mediated by an effect of ELFMF upon the serotonin metabolism and conclude that future tests of ELFMF effects should also measure serotonin levels and consider association with the seasonal effects (photoperiod or temperature) during the exposure.

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 typerandomized_trial

Effect directionmixed

Population1-2 months old cattle calves

Sample sizeNot supplied

ExposureELF · 0.05 MHz

Evidence strengthModerateConfidence: 70% · Peer reviewed: yes

Main findings

Outcomes measured

melatonin levels

Limitations

Sample size not specified
Duration of exposure not detailed
Mechanistic pathways hypothesized but not confirmed

View raw extracted JSON

{
  "study_type": "randomized_trial",
  "exposure": {
    "band": "ELF",
    "source": null,
    "frequency_mhz": 0.05,
    "sar_wkg": null,
    "duration": null
  },
  "population": "1-2 months old cattle calves",
  "sample_size": null,
  "outcomes": [
    "melatonin levels"
  ],
  "main_findings": "Exposure to 50 Hz extremely low frequency magnetic fields inhibited melatonin secretion in calves during winter, but increased melatonin concentration in summer. The inhibitory effect in winter was stronger than the positive effect in summer.",
  "effect_direction": "mixed",
  "limitations": [
    "Sample size not specified",
    "Duration of exposure not detailed",
    "Mechanistic pathways hypothesized but not confirmed"
  ],
  "evidence_strength": "moderate",
  "confidence": 0.7,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "extremely low frequency magnetic fields",
    "melatonin",
    "calves",
    "seasonal effect",
    "serotonin metabolism"
  ],
  "suggested_hubs": [
    {
      "slug": "occupational-exposure",
      "weight": 0.3,
      "reason": "Study of ELF magnetic field exposure relevant to biological effects"
    },
    {
      "slug": "who-icnirp",
      "weight": 0.7,
      "reason": "Study addresses health effects of ELF magnetic fields relevant to exposure guidelines"
    }
  ]
}

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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: 10.1038/srep14206
PubMed: Not supplied

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