Biological and Health-Related Effects of Weak Static Magnetic Fields (≤ 1 mT) in Humans and Vertebrates: A
Abstract
Biological and Health-Related Effects of Weak Static Magnetic Fields (≤ 1 mT) in Humans and Vertebrates: A Systematic Review Sarah Driessen, Lambert Bodewein, Dagmar Dechent, David Graefrath, Kristina Schmiedchen, Dominik Stunder, Thomas Kraus, Anne-Kathrin Petri. Biological and Health-Related Effects of Weak Static Magnetic Fields (≤ 1 mT) in Humans and Vertebrates: A Systematic Review. PLoS One. 2020 Jun 9;15(6):e0230038. doi: 10.1371/journal.pone. Abstract Background: There is a rapid development in technologies that generate weak static magnetic fields (SMF) including high-voltage direct current (HVDC) lines, systems operating with batteries, such as electric cars, and devices using permanent magnets. However, few reviews on the effects of such fields on biological systems have been prepared and none of these evaluations have had a particular focus on weak SMF (≤ 1 mT). The aim of this review was to systematically analyze and evaluate possible effects of weak SMF (≤ 1 mT) on biological functioning and to provide an update on the current state of research. Methods: This review was prepared in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement. Methodological limitations in individual studies were assessed using the Office of Health Assessment and Translation (OHAT) Risk-of-Bias Rating Tool. Results: Eleven studies fulfilled the eligibility criteria and were included in this review. All included studies were experimental animal studies as no human studies were among the eligible articles. Eight of the eleven studies reported responses of rat, rabbits and quails to weak SMF exposure that were expressed as altered melatonin biosynthesis, reduced locomotor activity, altered vasomotion and blood pressure, transient changes in blood pressure-related biochemical parameters, or in the level of neurotransmitters and increases in enzyme activities. It remained largely unclear from the interpretation of the results whether the reported effects in the evaluated studies were beneficial or detrimental for health. Conclusion: The available evidence from the literature reviewed is not sufficient to draw a conclusion for biological and health-related effects of exposure to weak SMF. There was a lack of homogeneity regarding the exposed biological systems and the examined endpoints as well as a lack of scientific rigor in most reviewed studies which lowered credibility in the reported results. We therefore encourage further and more systematic research in this area. Any new studies should particularly address effects of exposure to SMF on biological functioning in humans to evaluate whether SMF pose a risk to human health. Conflict of interest statement The authors have declared that no competing interests existed during the conduct of the study. However, during the revision of the document, DS has become an employee of Amprion GmbH, a German grid operator. Open access paper: journals.plos.org
AI evidence extraction
Main findings
This PRISMA-based systematic review included 11 eligible studies, all of which were experimental animal studies (no human studies met eligibility). Eight studies reported biological responses to weak static magnetic field exposure (≤ 1 mT), including changes in melatonin biosynthesis, locomotor activity, vasomotion/blood pressure, biochemical parameters, neurotransmitters, and enzyme activities. The authors conclude that evidence is insufficient to draw conclusions about biological or health-related effects due to heterogeneity and methodological limitations in most studies.
Outcomes measured
- Melatonin biosynthesis
- Locomotor activity
- Vasomotion
- Blood pressure
- Blood pressure-related biochemical parameters
- Neurotransmitter levels
- Enzyme activities
Limitations
- No eligible human studies were found
- Heterogeneity of exposed biological systems and endpoints
- Lack of scientific rigor in most reviewed studies, lowering credibility
- Unclear whether reported effects were beneficial or detrimental
Suggested hubs
-
power-lines
(0.62) The background explicitly mentions high-voltage direct current (HVDC) lines as a source of weak static magnetic fields.
View raw extracted JSON
{
"publication_year": 2020,
"study_type": "systematic_review",
"exposure": {
"band": "static",
"source": "HVDC lines, battery-operated systems (e.g., electric cars), permanent magnets",
"frequency_mhz": null,
"sar_wkg": null,
"duration": null
},
"population": "Vertebrate animals (rats, rabbits, quails); no eligible human studies",
"sample_size": 11,
"outcomes": [
"Melatonin biosynthesis",
"Locomotor activity",
"Vasomotion",
"Blood pressure",
"Blood pressure-related biochemical parameters",
"Neurotransmitter levels",
"Enzyme activities"
],
"main_findings": "This PRISMA-based systematic review included 11 eligible studies, all of which were experimental animal studies (no human studies met eligibility). Eight studies reported biological responses to weak static magnetic field exposure (≤ 1 mT), including changes in melatonin biosynthesis, locomotor activity, vasomotion/blood pressure, biochemical parameters, neurotransmitters, and enzyme activities. The authors conclude that evidence is insufficient to draw conclusions about biological or health-related effects due to heterogeneity and methodological limitations in most studies.",
"effect_direction": "unclear",
"limitations": [
"No eligible human studies were found",
"Heterogeneity of exposed biological systems and endpoints",
"Lack of scientific rigor in most reviewed studies, lowering credibility",
"Unclear whether reported effects were beneficial or detrimental"
],
"evidence_strength": "low",
"confidence": 0.7800000000000000266453525910037569701671600341796875,
"peer_reviewed_likely": "yes",
"stance": "neutral",
"stance_confidence": 0.7399999999999999911182158029987476766109466552734375,
"summary": "This systematic review assessed experimental evidence on weak static magnetic fields (≤ 1 mT) relevant to technologies such as HVDC lines, battery-powered systems, and permanent magnets. Eleven eligible studies were identified, all in vertebrate animals, with eight reporting various biological changes (e.g., melatonin, activity, blood pressure-related measures). The authors state that the evidence is insufficient to draw conclusions about health-related effects due to heterogeneity and methodological limitations, and they call for more systematic research, especially in humans.",
"key_points": [
"The review focused specifically on weak static magnetic fields at or below 1 mT.",
"The review followed PRISMA and assessed study limitations using the OHAT Risk-of-Bias tool.",
"Eleven studies met eligibility criteria and all were experimental animal studies, with no eligible human studies.",
"Eight studies reported biological responses including altered melatonin biosynthesis and reduced locomotor activity.",
"Reported outcomes also included altered vasomotion and blood pressure and transient changes in related biochemical parameters.",
"The authors report that it was largely unclear whether observed changes were beneficial or detrimental for health.",
"The review concludes that evidence is insufficient due to heterogeneity and limited scientific rigor in most studies.",
"The authors encourage further systematic research, particularly studies in humans."
],
"categories": [
"Static Magnetic Fields",
"Animal Studies",
"Systematic Reviews",
"Risk Assessment"
],
"tags": [
"Static Magnetic Fields",
"Weak SMF",
"1 mT",
"Systematic Review",
"PRISMA",
"OHAT Risk of Bias",
"HVDC Lines",
"Permanent Magnets",
"Electric Cars",
"Melatonin",
"Blood Pressure",
"Locomotor Activity",
"Neurotransmitters",
"Enzyme Activity",
"Vertebrates"
],
"keywords": [
"weak static magnetic fields",
"SMF",
"≤ 1 mT",
"systematic review",
"animal studies",
"melatonin",
"blood pressure",
"vasomotion",
"locomotor activity",
"neurotransmitters",
"enzymes",
"HVDC"
],
"suggested_hubs": [
{
"slug": "power-lines",
"weight": 0.61999999999999999555910790149937383830547332763671875,
"reason": "The background explicitly mentions high-voltage direct current (HVDC) lines as a source of weak static magnetic fields."
}
],
"social": {
"tweet": "Systematic review (PLoS One, 2020) on weak static magnetic fields (≤1 mT) found 11 eligible studies—all in animals, none in humans. Eight reported biological changes (e.g., melatonin, activity, blood pressure), but evidence was insufficient due to heterogeneity and study limitations.",
"facebook": "A 2020 PLoS One systematic review examined weak static magnetic fields (≤1 mT) from sources like HVDC lines, battery-powered systems, and permanent magnets. It identified 11 eligible studies, all in animals (no eligible human studies). While several studies reported biological changes (e.g., melatonin and blood pressure-related measures), the authors conclude evidence is insufficient due to heterogeneity and methodological limitations, and call for more rigorous research—especially in humans.",
"linkedin": "PLoS One (2020) systematic review on weak static magnetic fields (≤1 mT) relevant to HVDC lines, battery systems, and permanent magnets: 11 eligible studies were found, all experimental animal studies (no eligible human studies). Several reported biological changes (melatonin, locomotor activity, blood pressure-related outcomes), but the authors conclude evidence is insufficient due to heterogeneity and methodological limitations, highlighting the need for more rigorous human research."
}
}
AI can be wrong. Always verify against the paper.
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