Evidence map›Paper›PMID 40335291›Full record

ArticleEnvironmental health and preventive medicine2025

Single exposure to near-threshold 5G millimeter wave modifies restraint stress responses in rats.

Akiko Matsumoto, Ikumi Endo, Etsuko Ijima, Akimasa Hirata, Sachiko Kodera, Masayoshi Ichiba, Mikiko Tokiya, Takashi Hikage, Hiroshi Masuda

Abstract read
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Article in Environmental health and preventive medicine, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 2 papers.

0numbers the graph read from it
0cells of the map it votes in
2citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

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3 · Its place in the literature

Who cites it

2 citing papers in PubMed.

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4 · The record

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PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

9 authors.

Akiko MatsumotoDepartment of Social and Environmental Medicine, Saga University School of Medicine.ORCID http://orcid.org/0000-0002-8445-4071
Ikumi EndoDepartment of Social and Environmental Medicine, Saga University School of Medicine.
Etsuko IjimaDepartment of Environmental Medicine, Kurume University School of Medicine.
Akimasa HirataDepartment of Electrical and Mechanical Engineering, Nagoya Institute of Technology.
Sachiko KoderaDepartment of Electrical and Mechanical Engineering, Nagoya Institute of Technology.
Masayoshi IchibaDepartment of Social and Environmental Medicine, Saga University School of Medicine.
Mikiko TokiyaDepartment of Social and Environmental Medicine, Saga University School of Medicine.
Takashi HikageFaculty of Information Science and Technology, Hokkaido University.
Hiroshi MasudaDepartment of Environmental Medicine, Kurume University School of Medicine.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundIn response to growing concerns about the health effects of quasi-millimeter waves (qMMW) used in 5th-generation wireless systems, conservative whole-body exposure thresholds based on indirect evidence have been proposed. The guidelines define a whole-body average specific absorption rate (WBA-SAR) of 4 W/kg which causes a 1 °C increase in core temperature, as the operational threshold for adverse health effects. To address the lack of direct evidence, we recently reported that a 30-minute exposure to qMMW at 4.6 W/kg resulted in a 1 °C increase in rat core temperature. Here, we further analyzed the near-threshold stress response for the first time, using biological samples from the aforementioned and additional experiments.

methodsA total of 59 young Sprague-Dawley rats (240-322 g) were exposed to 28 GHz for 40 minutes at WBA-SARs of 0, 3.7, and 7.2 W/kg, under normal (22.5 °C, 45-55% humidity), and heat (32 °C, 70% humidity) conditions. Rats were restrained in acrylic holders for dose control. We repeatedly measured serum and urinary biomarkers of stress response, aggregated the data, and analyzed them using a single statistical mixed model to subtract the effects of sham exposure and between-subject variation.

resultsSham exposure induced stress responses, suggesting an effect of restraint. After the subtraction of the sham exposure effect, 28 GHz appeared to induce stress responses as evidenced by elevated serum-free corticosterone 1 or 3 days after the exposure, which was more evident in animals with a change in rectal temperature exceeding 1 °C. Urinary-free catecholamines demonstrated an inhibitory property of 28 GHz frequency exposure on the stress response as evidenced by noradrenaline on the day of exposure. Heat exposure enhanced this effect, suggesting a possible role of noradrenaline in heat dissipation by promoting cutaneous blood flow, a notion supported by the correlation between noradrenaline levels and tail surface temperature, a critical organ for heat dissipation.

conclusionsThis study is the first to demonstrate that qMMW whole-body exposure can alter the stress response as indicated by corticosterone and noradrenaline at near-threshold levels. Our findings may provide insight into the biological basis of the whole-body exposure thresholds in the international guidelines.

Indexed as

MicrowavesRestraint, PhysicalStress, PhysiologicalAnimalsBiomarkersCorticosteroneMaleRatsRats, Sprague-DawleyBiomarkersCorticosterone5GQuasi-millimeter wavesStress response biomarkersTemperatureWhole-body exposure

Identifiers

PMID40335291
PMCPMC12062831

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.