Modelling of daily radiofrequency electromagnetic field dose for a prospective adolescent cohort

Abstract

Modelling of daily radiofrequency electromagnetic field dose for a prospective adolescent cohort Eeftens M, Shen C, Jana Sönksen J, Schmutz C, van Wel L, Liorni I, Vermeulen R, Cardis E, Wiart J, Toledano M, Röösli M. Modelling of daily radiofrequency electromagnetic field dose for a prospective adolescent cohort. Environment International. 2023. doi: 10.1016/j.envint.2023.107737. Highlights • First longitudinal study to estimate daily RF-EMF dose of 6152 U.K. adolescents at ages 12 and 14. • At baseline (age 12), mean daily whole body RF-EMF dose was 170 mJ/kg/day. • Two years later, whole body dose was similar, but brain dose increased (+32% for temporal lobe). • The main contributor to the head and brain was own device use, in particular 2G mobile calls. • Dose at baseline and follow-up were correlated between 0.25 and 0.36 for various tissues. Abstract Introduction Radiofrequency electromagnetic fields originate from a variety of wireless communication sources operating near and far from the body, making it challenging to quantify daily absorbed dose. In the framework of the prospective cohort SCAMP (Study of Cognition, Adolescents and Mobile Phones), we aimed to characterize RF-EMF dose over a 2-year period. Methods The SCAMP cohort included 6605 children from greater London, UK at baseline (age 12.1 years; 2014- 2016) and 5194 at follow-up (age 14.2; 2016-2018). We estimated the daily dose of RF-EMF to eight tissues including the whole body and whole brain, using dosimetric algorithms for the specific absorption rate transfer into the body. We considered RF-EMF dose from 12 common usage scenarios such as mobile phone calls or data transmission. We evaluated the association between sociodemographic factors (gender, ethnicity, phone ownership and socio-economic status), and the dose change between baseline and follow-up. Results Whole body dose was estimated at an average of 170 mJ/kg/day at baseline and 178 mJ/kg/day at follow-up. Among the eight tissues considered, the right temporal lobe received the highest daily dose (baseline 1150 mJ/kg/day, follow-up 1520 mJ/kg/day). Estimated daily dose [mJ/kg/day] increased between baseline and follow-up for head and brain related tissues, but remained stable for the whole body and heart. Doses estimated at baseline and follow-up showed low correlation among the 3384 children who completed both assessments. Asian ethnicity (compared to white) and owning a bar phone or no phone (as opposed to a smartphone) were associated with lower estimated whole-body and whole-brain RF-EMF dose, while black ethnicity, a moderate/low socio-economic status (compared to high), and increasing age (at baseline) were associated with higher estimated RF-EMF dose. Conclusion This study describes the first longitudinal exposure assessment for children in a critical period of development. Dose estimations will be used in further epidemiological analyses for the SCAMP study. Excerpts A more critical issue for dose estimation is the type of mobile phone network. The RF-EMF dose model puts the output power of calling on a mobile phone on the 2G and 3G networks at 89.7 mW and 0.45 mW respectively, which is a large difference and explains the relative importance of the 2G calls for total dose. The model does not include a scenario for 4G, but we assumed the emitted radiation to be equal to that of 3G (Joshi, 2017). We did not have information on proportion of 2G/3G/4G use in the cohort (5G was still not relevant at the time of data collection), and assumed that 2G, 3G and 4G were each used approximately one third of the time for both baseline and follow-up, but this assumption could not be validated. Considering the importance of 2G in dose modelling, any change of this ratio within the two years would have noticeable impact on the dose estimate. Thus, we cannot rule out that decrease in 2G use over the study period may have overcompensated the increased usage, which would mean that the RF-EMF dose would have actually decreased over time.... Conclusion This study in a large sample of adolescents confirms that mobile phone use is the main contributor to daily RF- EMF dose for the whole body and various brain regions. The correlation between individual dose estimates within two years was relatively low, likely reflecting both dynamic changes in mobile device usage in this age group, as well as uncertainty when estimating own wireless communication use. This calls for repeated exposure assessment in longitudinal studies on RF-EMF. Open access paper: sciencedirect.com

AI evidence extraction

Main findings

Using dosimetric algorithms across 12 usage scenarios, mean estimated whole-body RF-EMF dose was 170 mJ/kg/day at baseline and 178 mJ/kg/day at follow-up. Estimated doses increased for head/brain-related tissues (e.g., right temporal lobe 1150 to 1520 mJ/kg/day) while remaining stable for whole body and heart; own device use (notably 2G mobile calls) was the main contributor to head/brain dose. Individual dose estimates at baseline and follow-up were lowly correlated among children completing both assessments, and ethnicity, phone type/ownership, socio-economic status, and age were associated with dose differences.

Outcomes measured

• Estimated daily RF-EMF absorbed dose (mJ/kg/day) to whole body and specific tissues (including whole brain, right temporal lobe, heart)
• Change in estimated dose between baseline and follow-up
• Correlation of individual dose estimates between baseline and follow-up
• Associations of sociodemographic factors (gender, ethnicity, phone ownership, socio-economic status, age) with estimated dose

Limitations

• Dose estimates are model-based (dosimetric algorithms) rather than direct measurements.
• Model did not include a specific 4G scenario; 4G emissions were assumed equal to 3G.
• No information on proportion of 2G/3G/4G use; assumed each one-third, which could not be validated.
• Authors note uncertainty that changes in 2G use over time could materially affect estimated dose trends.

Suggested hubs

• occupational-exposure (0.05)
  Not occupational; included only if portal uses this hub for general exposure assessment (weak match).

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    "study_type": "exposure_assessment",
    "exposure": {
        "band": "RF",
        "source": "mobile phone (own device use) and other wireless communication usage scenarios",
        "frequency_mhz": null,
        "sar_wkg": null,
        "duration": "daily dose estimated at baseline (age ~12; 2014–2016) and follow-up ~2 years later (age ~14; 2016–2018)"
    },
    "population": "UK adolescents (greater London) in the SCAMP cohort",
    "sample_size": 6605,
    "outcomes": [
        "Estimated daily RF-EMF absorbed dose (mJ/kg/day) to whole body and specific tissues (including whole brain, right temporal lobe, heart)",
        "Change in estimated dose between baseline and follow-up",
        "Correlation of individual dose estimates between baseline and follow-up",
        "Associations of sociodemographic factors (gender, ethnicity, phone ownership, socio-economic status, age) with estimated dose"
    ],
    "main_findings": "Using dosimetric algorithms across 12 usage scenarios, mean estimated whole-body RF-EMF dose was 170 mJ/kg/day at baseline and 178 mJ/kg/day at follow-up. Estimated doses increased for head/brain-related tissues (e.g., right temporal lobe 1150 to 1520 mJ/kg/day) while remaining stable for whole body and heart; own device use (notably 2G mobile calls) was the main contributor to head/brain dose. Individual dose estimates at baseline and follow-up were lowly correlated among children completing both assessments, and ethnicity, phone type/ownership, socio-economic status, and age were associated with dose differences.",
    "effect_direction": "unclear",
    "limitations": [
        "Dose estimates are model-based (dosimetric algorithms) rather than direct measurements.",
        "Model did not include a specific 4G scenario; 4G emissions were assumed equal to 3G.",
        "No information on proportion of 2G/3G/4G use; assumed each one-third, which could not be validated.",
        "Authors note uncertainty that changes in 2G use over time could materially affect estimated dose trends."
    ],
    "evidence_strength": "moderate",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "RF-EMF",
        "radiofrequency electromagnetic fields",
        "dose modelling",
        "specific absorption rate",
        "adolescents",
        "SCAMP cohort",
        "mobile phone use",
        "2G",
        "3G",
        "4G assumption",
        "longitudinal exposure assessment",
        "brain dose",
        "whole-body dose"
    ],
    "suggested_hubs": [
        {
            "slug": "occupational-exposure",
            "weight": 0.05000000000000000277555756156289135105907917022705078125,
            "reason": "Not occupational; included only if portal uses this hub for general exposure assessment (weak match)."
        }
    ]
}

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