Moon J, Kwon J, Mun Y. Relationship between radiofrequency-electromagnetic radiation from cellular

Abstract

Moon J, Kwon J, Mun Y. Relationship between radiofrequency-electromagnetic radiation from cellular phones and brain tumor: meta-analyses using various proxies for RF-EMR exposure-outcome assessment. Environ Health 23, 82 (2024). doi.org. Abstract Introduction The authors conducted meta-analyses regarding the association between cellular and mobile phone use and brain tumor development by applying various radiofrequency-electromagnetic radiation (RF-EMR) exposure subcategories. With changing patterns of mobile phone use and rapidly developing Wireless Personal Area Network (WPAN) technology (such as Bluetooth), this study will provide insight into the importance of more precise exposure subcategories for RF-EMR. Methods The medical librarian searched MEDLINE (PubMed), EMBASE, and the Cochrane Library until 16 December 2020. Results In these meta-analyses, 19 case-control studies and five cohort studies were included. Ipsilateral users reported a pooled odds ratio (OR) of 1.40 (95% CI 1.21–1.62) compared to non-regular users. Users with years of use over 10 years reported a pooled OR of 1.27 (95% CI 1.08–1.48). When stratified by each type of brain tumor, only meningioma (OR 1.20 (95% CI 1.04–1.39)), glioma (OR 1.45 (95% CI 1.16– 1.82)), and malignant brain tumors (OR 1.93 (95% CI 1.55–2.39)) showed an increased OR with statistical significance for ipsilateral users. For users with years of use over 10 years, only glioma (OR 1.32 (95% CI 1.01–1.71)) showed an increased OR with statistical significance. When 11 studies with an OR with cumulative hours of use over 896 h were synthesized, the pooled OR was 1.59 (95% CI 1.25–2.02). When stratified by each type of brain tumor, glioma, meningioma, and acoustic neuroma reported the pooled OR of 1.66 (95% CI 1.13–2.44), 1.29 (95% CI 1.08–1.54), and 1.84 (95% CI 0.78–4.37), respectively. For each individual study that considered cumulative hours of use, the highest OR for glioma, meningioma, and acoustic neuroma was 2.89 (1.41–5.93) (both side use, > 896 h), 2.57 (1.02–6.44) (both side use, > 896 h), and 3.53 (1.59–7.82) (ipsilateral use, > 1640 h), respectively. For five cohort studies, the pooled risk ratios (RRs) for all CNS tumors, glioma, meningioma, and acoustic neuroma, were statistically equivocal, respectively. However, the point estimates for acoustic neuroma showed a rather increased pooled RR for ever-use (1.26) and over 10 years of use (1.61) compared to never-use, respectively. Excerpts “In consideration of these rapidly changing mobile phone technologies, the currently used proxies for RF-EMR exposure assessment are crude and insufficient to clarify the relationship between RF-EMR exposure from cell phones and brain tumor incidence.... The usual exposure measures, such as the years of mobile phone use, the cumulative duration of calls, and the number of calls per week, are rough indicators of mobile phone use.... the authors conducted a series of meta-analyses and subgroup analyses using various exposure measuring categories, from crude to more precise ones. In consideration of crude exposure classifications used in previous meta-analyses, this study will give insight into the importance of more precise exposure subcategories in investigating this topic." "... the authors analyzed the risk of bias regarding selection and recall bias for the amount of cell phone use and misclassification and recall bias for ipsilateral/contralateral use. A major reason was that typical risk of bias rating tools such as the National Toxicology Program Office of Health Assessment and Translation Risk of Bias rating tool (NTP OHAT RoB rating tool, Supplementary material B) were not appropriate for assessing individual studies regarding this topic." [Note: The WHO systematic reviews relied on this rating tool.] "With the conversion from 2G cellular phones through 3G and 4G mobile phones to current 5G mobile phones, transmission of large data became possible. With the introduction of 3G technology, all aspects of our society and daily lives have changed drastically. Currently, we are using mobile phones nearly continuously and putting mobile phones near our bodies even when we are not using them. For example, if people use their mobile phone for morning-alarming purposes, they might put their mobile phone near the bed, sometimes even beside their head, all night. These changed patterns of mobile phone use could increase exposure to RF-EMR from cellular and mobile phones. Therefore, precise exposure assessment for RF-EMR from mobile phones would become more complex in future studies." "The results of cumulative meta-analyses according to precision indicated that the pooled OR was biased downwards with the addition of studies with lower precision. This indicates that the results of studies with a lower precision should be interpreted cautiously." "Because brain tumors require a latency period to develop [29], an accurate assessment of brain tumor risk associated with RF-EMR exposure requires a long observation span. However, each included study did not consider a sufficient latency period in their study design. This could have led to a possible underestimation of brain tumor risk. Future studies with long observation spans might resolve this problem.” "In this meta-analysis, as the applied exposure subcategories became more concrete, the pooled ORs showed more increased values with statistical significance. Even though the meta-analysis of cohort studies showed statistically equivocal pooled effect estimates, (i) as the number of included studies increases and (ii) as the applied exposure subcategory becomes more concrete, the pooled RRs could show a different aspect in future studies. Furthermore, changing patterns of mobile phone use and increasing use of earphones or headphones with WPAN technology should be sufficiently considered in future studies. Relatively short observation spans for brain tumor incidence and age of starting exposure and brain tumor diagnosis should also be considered in future studies. Previous studies that adjusted for selection and recall bias for the amount of cellphone use and misclassification and recall bias for ipsilateral/contralateral use showed possible underestimations of previous risk estimates. Future studies should try to adjust for these biases in their study design." Open access paper: ehjournal.biomedcentral.com Supplementary material: static-content.springer.com 01117-8/MediaObjects/12940_2024_1117_MOESM1_ESM.docx

AI evidence extraction

Main findings

This meta-analysis of 19 case-control and five cohort studies reported increased pooled odds ratios for brain tumors in several higher-exposure proxy categories, including ipsilateral use (OR 1.40) and >10 years of use (OR 1.27) versus non-regular users. By tumor type, statistically significant increased odds were reported for ipsilateral use for meningioma, glioma, and malignant brain tumors, and for >10 years of use for glioma. Cohort-study pooled risk ratios were described as statistically equivocal, though point estimates for acoustic neuroma were higher for ever-use and >10 years of use versus never-use.

Outcomes measured

• Brain tumor incidence/risk
• Glioma
• Meningioma
• Malignant brain tumors
• Acoustic neuroma
• All CNS tumors

Limitations

• Searches were conducted up to 16 December 2020 (newer studies not included).
• Exposure assessment relied on proxies (e.g., years of use, cumulative call hours, ipsilateral/contralateral use) that the authors describe as crude and potentially misclassified.
• Potential selection and recall bias in included studies (including for amount of use and ipsilateral/contralateral reporting) is discussed.
• Included studies may not have incorporated sufficient latency/observation periods for brain tumor development.
• Cohort-study pooled estimates were statistically equivocal, indicating uncertainty in prospective evidence as summarized here.

Suggested hubs

• cell-phones (0.95)
  Focuses on cellular/mobile phone RF-EMR exposure and brain tumor outcomes.

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    "study_type": "meta_analysis",
    "exposure": {
        "band": "RF",
        "source": "mobile phone",
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        "sar_wkg": null,
        "duration": "Ever-use; >10 years; cumulative hours (e.g., >896 h; >1640 h); ipsilateral vs contralateral use"
    },
    "population": "Human mobile/cellular phone users (case-control and cohort study participants)",
    "sample_size": null,
    "outcomes": [
        "Brain tumor incidence/risk",
        "Glioma",
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        "Malignant brain tumors",
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    "main_findings": "This meta-analysis of 19 case-control and five cohort studies reported increased pooled odds ratios for brain tumors in several higher-exposure proxy categories, including ipsilateral use (OR 1.40) and >10 years of use (OR 1.27) versus non-regular users. By tumor type, statistically significant increased odds were reported for ipsilateral use for meningioma, glioma, and malignant brain tumors, and for >10 years of use for glioma. Cohort-study pooled risk ratios were described as statistically equivocal, though point estimates for acoustic neuroma were higher for ever-use and >10 years of use versus never-use.",
    "effect_direction": "mixed",
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        "Searches were conducted up to 16 December 2020 (newer studies not included).",
        "Exposure assessment relied on proxies (e.g., years of use, cumulative call hours, ipsilateral/contralateral use) that the authors describe as crude and potentially misclassified.",
        "Potential selection and recall bias in included studies (including for amount of use and ipsilateral/contralateral reporting) is discussed.",
        "Included studies may not have incorporated sufficient latency/observation periods for brain tumor development.",
        "Cohort-study pooled estimates were statistically equivocal, indicating uncertainty in prospective evidence as summarized here."
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    "summary": "This 2024 meta-analysis evaluated associations between mobile/cellular phone use (using multiple exposure proxies) and brain tumors, including 19 case-control and five cohort studies. It reports higher pooled odds ratios in several higher-exposure proxy categories, such as ipsilateral use and long-term or high cumulative call hours, with statistically significant increases for some tumor subtypes (notably glioma and meningioma in certain analyses). Pooled cohort-study risk ratios were described as statistically equivocal, although acoustic neuroma point estimates were elevated for ever-use and >10 years of use. The authors emphasize limitations of crude exposure proxies and potential biases that could affect estimates.",
    "key_points": [
        "The authors conducted meta-analyses using multiple RF-EMR exposure proxy subcategories (e.g., ipsilateral use, years of use, cumulative hours).",
        "Nineteen case-control studies and five cohort studies were included based on searches through 16 December 2020.",
        "For case-control studies, ipsilateral users had a pooled OR of 1.40 versus non-regular users.",
        "For case-control studies, >10 years of use had a pooled OR of 1.27 versus non-regular users.",
        "By tumor type, statistically significant increased odds for ipsilateral use were reported for meningioma, glioma, and malignant brain tumors.",
        "For cumulative hours >896 h, the pooled OR was 1.59, with glioma and meningioma showing increased pooled ORs in stratified analyses.",
        "For cohort studies, pooled RRs for CNS tumors and specific tumor types were described as statistically equivocal, with higher point estimates noted for acoustic neuroma.",
        "The paper argues that less precise exposure classifications may bias pooled estimates downward and that future studies should improve exposure assessment and consider latency."
    ],
    "categories": [
        "RF-EMF",
        "Cell Phones",
        "Cancer",
        "Epidemiology",
        "Systematic Reviews & Meta-analyses"
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    "tags": [
        "Mobile Phones",
        "Radiofrequency Exposure",
        "Brain Tumors",
        "Glioma",
        "Meningioma",
        "Acoustic Neuroma",
        "Ipsilateral Use",
        "Cumulative Call Time",
        "Long-Term Use",
        "Case-Control Studies",
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        "Exposure Misclassification",
        "Recall Bias",
        "Selection Bias",
        "Latency Period"
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        "cellular phones",
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        "brain tumor",
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    "social": {
        "tweet": "2024 meta-analysis (19 case-control, 5 cohort) examined mobile phone RF-EMR exposure proxies and brain tumors. Higher pooled odds were reported for ipsilateral use and high/long-term use in some analyses (notably glioma/meningioma), while cohort pooled RRs were statistically equivocal. doi:10.1186/s12940-024-01117-8",
        "facebook": "A 2024 meta-analysis in Environmental Health assessed mobile phone RF-EMR exposure proxies (ipsilateral use, years of use, cumulative call hours) and brain tumor risk. It reported increased pooled odds in some higher-exposure categories (including glioma/meningioma in certain analyses), while pooled cohort-study risk ratios were described as statistically equivocal. doi:10.1186/s12940-024-01117-8",
        "linkedin": "Environmental Health (2024) meta-analysis of 19 case-control and 5 cohort studies evaluated mobile phone RF-EMR exposure proxies and brain tumors. Increased pooled odds were reported for some higher-exposure categories (e.g., ipsilateral use; high cumulative hours), while pooled cohort-study RRs were statistically equivocal; authors highlight exposure misclassification and bias considerations. doi:10.1186/s12940-024-01117-8"
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