Occupational exposure to high-frequency EMF and brain tumor risk in INTEROCC study

2018 · Mixed · Low evidence

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MixedLow evidencePaper 2063

Study snapshot

Publicationmanual · 2018

Study typecase_control

Reported directionMixed

Evidence ratingLow

Abstract

Occupational exposure to high-frequency EMF and brain tumor risk in INTEROCC study Vila J, Turner MC, Gracia-Lavedan E, Figuerola J, Bowman JD, Kincl L, Richardson L, Benke G, Hours M, Krewski D, McLean D, Parent ME, Sadetzki S, Schlaefer K, Schlehofer B, Schüz J, Siemiatycki J, van Tongeren M, Cardis E, INTEROCC Study Group.Occupational exposure to high-frequency electromagnetic fields and brain tumor risk in the INTEROCC study: An individualized assessment approach. Environ Int. 2018 Jul 8;119:353-365. doi: 10.1016/j.envint.2018.06.038. Introduction: In 2011, the International Agency for Research on Cancer classified radiofrequency (RF) electromagnetic fields (EMF) as possibly carcinogenic to humans (group 2B), although the epidemiological evidence for the association between occupational exposure to RF-EMF and cancer was judged to be inadequate, due in part to limitations in exposure assessment. This study examines the relation between occupational RF and intermediate frequency (IF) EMF exposure and brain tumor (glioma and meningioma) risk in the INTEROCC multinational population-based case-control study (with nearly 4000 cases and over 5000 controls), using a novel exposure assessment approach. Methods: Individual indices of cumulative exposure to RF and IF-EMF (overall and in specific exposure time windows) were assigned to study participants using a source-exposure matrix and detailed interview data on work with or nearby EMF sources. Conditional logistic regression was used to investigate associations with glioma and meningioma risk. Results: Overall, around 10% of study participants were exposed to RF while only 1% were exposed to IF-EMF. There was no clear evidence for a positive association between RF or IF-EMF and the brain tumors studied, with most results showing either no association or odds ratios (ORs) below 1.0. The largest adjusted ORs were obtained for cumulative exposure to RF magnetic fields (as A/m-years) in the highest exposed category (≥90th percentile) for the most recent exposure time window (1-4 years before the diagnosis or reference date) for both glioma, OR = 1.62 (95% confidence interval (CI): 0.86, 3.01) and meningioma (OR = 1.52, 95% CI: 0.65, 3.55). Conclusion: Despite the improved exposure assessment approach used in this study, no clear associations were identified. However, the results obtained for recent exposure to RF electric and magnetic fields are suggestive of a potential role in brain tumor promotion/progression and should be further investigated. ncbi.nlm.nih.gov Excerpt In conclusion, despite the improved quantitative exposure assessment used in this study, the results do not support a positive association between occupational exposure to high-frequency EMF and either glioma or meningioma risk. However, given our limited statistical power, due to the small number of exposed participants, and despite our results´ lack of significance (Greenland et al., 2016; Rothman, 2016; Smith and Kriebel, 2010), our findings foster the need for further research focusing on RF magnetic fields and tumor promotion, as well as possible interactions with other frequencies and with chemicals. Moreover, since most RF studies until now have focused on the effects of electric fields, more studies of RF magnetic fields are needed, particularly looking at differences between near-field (e.g. walkie-talkies) and far-field exposures (e.g. radars). Furthermore, the development of biology-based dose metrics which take into account both electric and magnetic fields from various sources (Hansson Mild and Mattson, 2017) may provide further insights on the potential biophysical mechanism(s), other than heating and nerve electro-stimulation (ICNIRP, 1998; IEEE, 2006), by which long-term exposure to high-frequency EMF may damage health.

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AI evidence extraction

Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.

Study typecase_control

Effect directionmixed

PopulationParticipants in the INTEROCC multinational population-based case-control study

Sample size9000

ExposureRF · cumulative exposure (overall and specific exposure time windows; includes recent 1–4 years before diagnosis/reference)

Evidence strengthLowConfidence: 78% · Peer reviewed: yes

Main findings

In this multinational population-based case-control study (nearly 4000 cases and over 5000 controls), there was no clear evidence for a positive association between occupational RF or intermediate frequency (IF)-EMF exposure and glioma or meningioma risk; most odds ratios were null or below 1.0. The largest adjusted odds ratios were observed for the highest category (≥90th percentile) of cumulative RF magnetic-field exposure in the most recent exposure window (1–4 years before diagnosis/reference): glioma OR 1.62 (95% CI 0.86–3.01) and meningioma OR 1.52 (95% CI 0.65–3.55).

Outcomes measured

Glioma risk
Meningioma risk
Brain tumor risk

Limitations

Limited statistical power due to small number of exposed participants (around 10% exposed to RF; 1% to IF-EMF)
Confidence intervals include 1.0 for the largest reported odds ratios

View raw extracted JSON

{
  "study_type": "case_control",
  "exposure": {
    "band": "RF",
    "source": "occupational",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": "cumulative exposure (overall and specific exposure time windows; includes recent 1–4 years before diagnosis/reference)"
  },
  "population": "Participants in the INTEROCC multinational population-based case-control study",
  "sample_size": 9000,
  "outcomes": [
    "Glioma risk",
    "Meningioma risk",
    "Brain tumor risk"
  ],
  "main_findings": "In this multinational population-based case-control study (nearly 4000 cases and over 5000 controls), there was no clear evidence for a positive association between occupational RF or intermediate frequency (IF)-EMF exposure and glioma or meningioma risk; most odds ratios were null or below 1.0. The largest adjusted odds ratios were observed for the highest category (≥90th percentile) of cumulative RF magnetic-field exposure in the most recent exposure window (1–4 years before diagnosis/reference): glioma OR 1.62 (95% CI 0.86–3.01) and meningioma OR 1.52 (95% CI 0.65–3.55).",
  "effect_direction": "mixed",
  "limitations": [
    "Limited statistical power due to small number of exposed participants (around 10% exposed to RF; 1% to IF-EMF)",
    "Confidence intervals include 1.0 for the largest reported odds ratios"
  ],
  "evidence_strength": "low",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "INTEROCC",
    "occupational exposure",
    "radiofrequency",
    "intermediate frequency",
    "electromagnetic fields",
    "RF magnetic fields",
    "RF electric fields",
    "glioma",
    "meningioma",
    "brain tumors",
    "case-control",
    "exposure assessment",
    "source-exposure matrix"
  ],
  "suggested_hubs": [
    {
      "slug": "occupational-exposure",
      "weight": 0.95,
      "reason": "Study evaluates occupational RF/IF-EMF exposure and brain tumor risk using individualized exposure assessment."
    }
  ]
}

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AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: 10.1016/j.envint.2018.06.038
PubMed: Not supplied

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