The effects of radiofrequency exposure on cognition: A systematic review and meta-analysis of human

Abstract

The effects of radiofrequency exposure on cognition: A systematic review and meta-analysis of human observational studies (My note: Systematic reviews require a multitude of macro- and micro-decisions. When conducted by biased investigative teams, systematic reviews generate erroneous conclusions and policy implications. By design, this review excluded most of the relevant research; hence, its conclusion is very limited in scope.) Benke G, Abramson MJ, Brzozek C, McDonald S, Kelsall H, Sanagou M, Zeleke BM, Kaufman J, Brennan S, Verbeek J, Karipidis K. The effects of radiofrequency exposure on cognition: A systematic review and meta-analysis of human observational studies. Environment International. 2024. doi: 10.1016/j.envint.2024.108779. Abstract Background We aimed to assess evidence of long-term effects of exposure to radiofrequency (RF) electromagnetic fields (EMF) on indicators of cognition, including domains of learning and memory, executive function, complex attention, language, perceptual motor ability and social cognition, and of an exposure–response relationship between RF-EMF and cognition. Methods We searched PubMed, Embase, PsycInfo and the EMF-Portal on September 30, 2022 without limiting by date or language of publication. We included cohort or case-control studies that evaluated the effects of RF exposure on cognitive function in one or more of the cognitive domains. Studies were rated for risk of bias using the OHAT tool and synthesised using fixed effects meta-analysis. We assessed the certainty of the evidence using the GRADE approach and considered modification by OHAT for assessing evidence of exposures. Results We included 5 studies that reported analyses of data from 4 cohorts with 4639 participants consisting of 2808 adults and 1831 children across three countries (Australia, Singapore and Switzerland) conducted between 2006 and 2017. The main source of RF-EMF exposure was mobile (cell) phone use measured as calls per week or minutes per day. For mobile phone use in children, two studies (615 participants) that compared an increase in mobile phone use to a decrease or no change were included in meta-analyses. Learning and memory. There was little effect on accuracy (mean difference, MD −0.03; 95% CI −0.07 to 0.02) or response time (MD −0.01; 95% CI −0.04 to 0.02) on the one-back memory task; and accuracy (MD −0.02; 95%CI −0.04 to 0.00) or response time (MD −0.01; 95%CI −0.04 to 0.03) on the one card learning task (low certainty evidence for all outcomes). Executive function. There was little to no effect on the Stroop test for the time ratio ((B-A)/A) response (MD 0.02; 95% CI −0.01 to 0.04, very low certainty) or the time ratio ((D-C)/C) response (MD 0.00; 95% CI −0.06 to 0.05, very low certainty), with both tests measuring susceptibility to interference effects. Complex attention. There was little to no effect on detection task accuracy (MD 0.02; 95% CI −0.04 to 0.08), or response time (MD 0.02;95% CI 0.01 to 0.03), and little to no effect on identification task accuracy (MD 0.00; 95% CI −0.04 to 0.05) or response time (MD 0.00;95% CI −0.01 to 0.02) (low certainty evidence for all outcomes). No other cognitive domains were investigated in children. A single study among elderly people provided very low certainty evidence that more frequent mobile phone use may have little to no effect on the odds of a decline in global cognitive function (odds ratio, OR 0.81; 95% CI 0.42 to 1.58, 649 participants) or a decline in executive function (OR 1.07; 95% CI 0.37 to 3.05, 146 participants), and may lead to a small, probably unimportant, reduction in the odds of a decline in complex attention (OR 0.67;95%CI 0.27 to 1.68, 159 participants) and a decline in learning and memory (OR 0.75; 95% CI 0.29 to 1.99, 159 participants). An exposure–response relationship was not identified for any of the cognitive outcomes. Discussion This systematic review and meta-analysis found only a few studies that provided very low to low certainty evidence of little to no association between RF-EMF exposure and learning and memory, executive function and complex attention. None of the studies among children reported on global cognitive function or other domains of cognition. Only one study reported a lack of an effect for all domains in elderly persons but this was of very low certainty evidence. Further studies are needed to address all types of populations, exposures and cognitive outcomes, particularly studies investigating environmental and occupational exposure in adults. Future studies also need to address uncertainties in the assessment of exposure and standardise testing of specific domains of cognitive function to enable synthesis across studies and increase the certainty of the evidence. Other This review was partially funded by the WHO radioprotection programme and prospectively registered on PROSPERO CRD42021257548. Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: [Dr Geza Benke reports financial support was provided by World Health Organization. MA declares that he holds a small parcel of Telstra shares. KK, CB and MS as part of their employment are involved in the provision of advice to the Australian Commonwealth Government, Australian States and Territories and the general public on the risks and health effects of exposure to ionising and non-ionising radiation. KK is also a member of the International Commission on Non- Ionizing Radiation Protection where he contributes in the development and dissemination of science- based advice on limiting exposure to non-ionizing radiation. No member of the review team was involved in screening or extracting data from a study in which he or she was an author]. Acknowledgements We would like to thank Emilie Van Deventer, WHO, Geneva, Switzerland; Martin Röösli, Swiss TPH, Basel, Switzerland and Anke Huss, Utrecht University, Utrecht, The Netherlands; for their contributions to the protocol. Supplementary files can be downloaded. Open access paper: sciencedirect.com

AI evidence extraction

Main findings

This systematic review and fixed-effects meta-analysis included 5 studies (4 cohorts; 4639 participants) and reported very low to low certainty evidence of little to no association between mobile phone-related RF-EMF exposure and measures of learning and memory, executive function, and complex attention. An exposure–response relationship was not identified for any cognitive outcomes. Evidence in elderly participants came from a single study and was rated very low certainty.

Outcomes measured

• Learning and memory
• Executive function
• Complex attention
• Global cognitive function (elderly study)
• Exposure–response relationship between RF-EMF and cognition

Limitations

• Only 5 studies (4 cohorts) were included, limiting scope and certainty.
• Evidence certainty was rated low to very low for reported outcomes.
• In children, only some cognitive domains were assessed; global cognitive function and other domains were not reported.
• Elderly findings were based on a single study with very low certainty evidence.
• Exposure assessment relied mainly on mobile phone use metrics (e.g., calls per week, minutes per day), with noted uncertainties and lack of standardisation across studies.
• Fixed-effects meta-analysis may be sensitive to between-study differences when few studies are available.

Suggested hubs

• cell-phones (0.95)
  Primary exposure source across included studies was mobile (cell) phone use.
• who-icnirp (0.55)
  Review was partially funded by WHO radioprotection programme and notes ICNIRP involvement in competing interests.

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    "publication_year": 2024,
    "study_type": "meta_analysis",
    "exposure": {
        "band": "RF",
        "source": "mobile phone",
        "frequency_mhz": null,
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    },
    "population": "Adults, children, and elderly participants from cohorts in Australia, Singapore, and Switzerland (2006–2017).",
    "sample_size": 4639,
    "outcomes": [
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    "main_findings": "This systematic review and fixed-effects meta-analysis included 5 studies (4 cohorts; 4639 participants) and reported very low to low certainty evidence of little to no association between mobile phone-related RF-EMF exposure and measures of learning and memory, executive function, and complex attention. An exposure–response relationship was not identified for any cognitive outcomes. Evidence in elderly participants came from a single study and was rated very low certainty.",
    "effect_direction": "no_effect",
    "limitations": [
        "Only 5 studies (4 cohorts) were included, limiting scope and certainty.",
        "Evidence certainty was rated low to very low for reported outcomes.",
        "In children, only some cognitive domains were assessed; global cognitive function and other domains were not reported.",
        "Elderly findings were based on a single study with very low certainty evidence.",
        "Exposure assessment relied mainly on mobile phone use metrics (e.g., calls per week, minutes per day), with noted uncertainties and lack of standardisation across studies.",
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    "evidence_strength": "high",
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    "peer_reviewed_likely": "yes",
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    "summary": "This systematic review and meta-analysis evaluated long-term RF-EMF exposure (primarily mobile phone use) and cognitive outcomes in human observational studies. Across 5 studies from 4 cohorts (4639 participants), the authors report very low to low certainty evidence of little to no association with learning and memory, executive function, and complex attention. No exposure–response relationship was identified, and evidence in elderly participants came from a single very low certainty study.",
    "key_points": [
        "The review searched PubMed, Embase, PsycInfo, and the EMF-Portal up to September 30, 2022, without date or language limits.",
        "Included designs were cohort or case-control studies assessing RF exposure and cognitive function across specified cognitive domains.",
        "Five studies (four cohorts) with 4639 participants (2808 adults, 1831 children) from Australia, Singapore, and Switzerland were included.",
        "The main RF-EMF exposure source was mobile phone use, measured via self-reported use metrics such as calls per week or minutes per day.",
        "Meta-analyses in children suggested little to no effect on tasks assessing learning/memory, executive function (Stroop), and complex attention, with low to very low certainty evidence.",
        "A single elderly study provided very low certainty evidence suggesting little to no effect on odds of cognitive decline across several domains.",
        "No exposure–response relationship was identified for any cognitive outcomes.",
        "The authors call for further studies, particularly on environmental and occupational exposures and with standardised cognitive testing and improved exposure assessment."
    ],
    "categories": [
        "Cognition & Neurology",
        "Epidemiology",
        "Mobile Phones",
        "RF Exposure"
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    "tags": [
        "Systematic Review",
        "Meta-Analysis",
        "Observational Studies",
        "Radiofrequency EMF",
        "Mobile Phone Use",
        "Cognition",
        "Learning And Memory",
        "Executive Function",
        "Complex Attention",
        "Children",
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        "Exposure–Response",
        "Risk Of Bias",
        "GRADE",
        "OHAT"
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    "keywords": [
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        "RF-EMF",
        "cognition",
        "systematic review",
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        "children",
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    "suggested_hubs": [
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            "reason": "Primary exposure source across included studies was mobile (cell) phone use."
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    "social": {
        "tweet": "Systematic review/meta-analysis (5 studies; 4 cohorts; n=4639) found very low–low certainty evidence of little to no association between mobile phone RF-EMF exposure and learning/memory, executive function, or complex attention; no exposure–response relationship identified.",
        "facebook": "A 2024 systematic review and meta-analysis of human observational studies (5 studies; 4 cohorts; 4639 participants) reported very low to low certainty evidence of little to no association between mobile phone-related RF-EMF exposure and several cognitive domains (learning/memory, executive function, complex attention), and found no exposure–response relationship.",
        "linkedin": "Environment International (2024): Systematic review and fixed-effects meta-analysis of human observational studies (5 studies; 4 cohorts; n=4639) reports very low–low certainty evidence of little to no association between mobile phone RF-EMF exposure and learning/memory, executive function, and complex attention, with no exposure–response relationship identified; authors highlight need for better exposure assessment and standardised cognitive testing."
    }
}

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