Review of biological effects of EMF in intermediate frequency range (300 Hz to 1 MHz)

2019 · Mixed · Insufficient evidence

← Research stream

MixedInsufficient evidencePaper 1897

Study snapshot

Publicationmanual · 2019

Study typesystematic_review

Reported directionMixed

Evidence ratingInsufficient

Abstract

Review of biological effects of EMF in intermediate frequency range (300 Hz to 1 MHz) Bodewein L, Schmiedchen K, Dechent D, Stunder D, Graefrath D, Winter L, Kraus T, Driessen S. Systematic review on the biological effects of electric, magnetic and electromagnetic fields in the intermediate frequency range (300 Hz to 1 MHz). Environ Res. 2019 Jan 9;171:247-259. doi: 10.1016/j.envres.2019.01.015. Highlights • Biological effects of intermediate frequency fields were systematically analyzed. • Fifty-six experimental studies were eligible. • Weak field strengths and frequencies > 100 kHz have been hardly investigated. • Low quality of evidence for adverse effects for most examined endpoints. • Methodical limitations lowered credibility of the results. Excerpt "... a few studies that were of moderate quality, revealed some potentially adverse effects of MF in the IF range, such as an increased number of abnormal chicken embryos (Juutilainen and Saali, 1986), or an increase in inflammatory mediators and oxidative stress markers in the young mouse brain (Win-Shwe et al., 2015). Such studies should be replicated by independent laboratories." Abstract BACKGROUND: Many novel technologies, including induction cookers or wireless power transfer, produce electric fields (EF), magnetic fields (MF) or electromagnetic fields (EMF) in the intermediate frequency (IF) range. The effects of such fields on biological systems, however, have been poorly investigated. The aim of this systematic review was to provide an update of the state of research and to evaluate the potential for adverse effects of EF, MF and EMF in the IF range (300 Hz to 1 MHz) on biological systems. METHODS: The review was prepared in accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Methodical limitations in individual studies were assessed using the Office of Health Assessment and Translation (OHAT) Risk of Bias Rating Tool for Human and Animal Studies. RESULTS: Fifty-six studies exposing humans, animals or in vitro systems were eligible for this review. In these studies, many different endpoints were examined and most of the findings were obtained in studies with exposure to MF. For most endpoints, however, the reviewed studies yielded inconsistent results, with some studies indicating no effect and some linking IF exposure with adverse effects. In the majority of the included studies, the applied field strengths were above the International Commission on Non-Ionizing Radiation Protection (ICNIRP) reference levels for the general public and the applied frequencies were mainly below 100 kHz. Furthermore, many of the reviewed studies suffered from methodical limitations which lowered the credibility of the reported results. CONCLUSION: Due to the large heterogeneity in study designs, endpoints and exposed systems, as well as the inconsistent results and methodical limitations in many studies, the quality of evidence for adverse effects remains inadequate for drawing a conclusion on investigated biological effects of IF fields for most endpoints. We recommend that in future studies, effects of EF, MF and EMF in the IF range should be investigated more systematically, i.e., studies should consider various frequencies to identify potential frequency-dependent effects and apply different field strengths, especially if threshold-dependent effects are expected. Priority should be given to the investigation of acute effects, like induction of phosphenes, perception, excitation of nerves or muscles and thermal effects. This would be an important step towards the validation of the reference levels recommended by ICNIRP. Furthermore, we recommend that any new studies aim at implementing high quality dosimetry and minimizing sources of risk of bias. 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 typesystematic_review

Effect directionmixed

PopulationNot supplied

Sample size56

ExposureIF

Evidence strengthInsufficientConfidence: 78% · Peer reviewed: yes

Main findings

This PRISMA-based systematic review included 56 experimental studies (human, animal, and in vitro) on electric, magnetic, and electromagnetic fields in the intermediate frequency range (300 Hz to 1 MHz). Across endpoints, results were inconsistent (some studies reported no effects while others reported adverse effects), and many studies had methodological limitations that reduced credibility; overall evidence for adverse effects was judged inadequate for most endpoints.

Outcomes measured

biological effects (various endpoints)
abnormal chicken embryos
inflammatory mediators
oxidative stress markers
phosphenes
perception
excitation of nerves or muscles
thermal effects

Limitations

Large heterogeneity in study designs, endpoints, and exposed systems
Inconsistent results across studies
Many included studies had methodological limitations/risk of bias lowering credibility
Weak field strengths and frequencies >100 kHz were hardly investigated
Most applied frequencies were mainly below 100 kHz
In many studies, applied field strengths were above ICNIRP reference levels for the general public

View raw extracted JSON

{
  "study_type": "systematic_review",
  "exposure": {
    "band": "IF",
    "source": "induction cookers or wireless power transfer",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": null
  },
  "population": null,
  "sample_size": 56,
  "outcomes": [
    "biological effects (various endpoints)",
    "abnormal chicken embryos",
    "inflammatory mediators",
    "oxidative stress markers",
    "phosphenes",
    "perception",
    "excitation of nerves or muscles",
    "thermal effects"
  ],
  "main_findings": "This PRISMA-based systematic review included 56 experimental studies (human, animal, and in vitro) on electric, magnetic, and electromagnetic fields in the intermediate frequency range (300 Hz to 1 MHz). Across endpoints, results were inconsistent (some studies reported no effects while others reported adverse effects), and many studies had methodological limitations that reduced credibility; overall evidence for adverse effects was judged inadequate for most endpoints.",
  "effect_direction": "mixed",
  "limitations": [
    "Large heterogeneity in study designs, endpoints, and exposed systems",
    "Inconsistent results across studies",
    "Many included studies had methodological limitations/risk of bias lowering credibility",
    "Weak field strengths and frequencies >100 kHz were hardly investigated",
    "Most applied frequencies were mainly below 100 kHz",
    "In many studies, applied field strengths were above ICNIRP reference levels for the general public"
  ],
  "evidence_strength": "insufficient",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "intermediate frequency",
    "300 Hz to 1 MHz",
    "systematic review",
    "PRISMA",
    "OHAT risk of bias",
    "electric fields",
    "magnetic fields",
    "electromagnetic fields",
    "ICNIRP reference levels",
    "induction cookers",
    "wireless power transfer"
  ],
  "suggested_hubs": [
    {
      "slug": "who-icnirp",
      "weight": 0.7,
      "reason": "Review discusses ICNIRP reference levels and validation of ICNIRP recommendations."
    },
    {
      "slug": "wireless-power-transfer",
      "weight": 0.55,
      "reason": "Background notes wireless power transfer as a source of intermediate-frequency fields."
    }
  ]
}

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: 10.1016/j.envres.2019.01.015
PubMed: Not supplied

Read the original paper →

Related papers

← Back to the Research Library