Calculated residential exposure to power frequency magnetic fields for an epidemiological study in France and comparison to measurements

Abstract

Calculated residential exposure to power frequency magnetic fields for an epidemiological study in France and comparison to measurements Deschamps F, Deambrogio V. Calculated residential exposure to power frequency magnetic fields for an epidemiological study in France and comparison to measurements. J Radiol Prot. 2023 Apr 27. doi: 10.1088/1361-6498/acd0b9. Abstract The GEOCAP epidemiological study of paediatric cancers in relation with various environmental factors is currently being carried out in France. Proximity to high voltage overhead lines (63-400kV) related to exposure to extremely low frequency magnetic field (ELF-MF) is one of studied factors. The study covers the mainland French territory and includes 4174 leukaemia cases and 45,000 controls recruited from 2002 to 2010. Residential exposure was calculated for 1124 subjects whose distance to power lines was small enough for their residential exposure to possibly exceed the background reference level 0.1µT. Residential exposure was calculated by modelling all the influencing spans close to the subjects' residences. At final, 371 subjects out of 1124 have a calculated exposure over 0.1µT, including 123 subjects over 0.4µT, i.e. 0.25% of the study population. These 371 calculated exposures exceeding 0.1µT have been matched to an existing database of ELF- MF measurements performed in inhabited areas crossed by power lines, and measurements were found for 206 subjects. Comparison was possible for 156 of them. After extrapolation of the measured values to match to calculation conditions, the difference between calculations and adjusted measurements was lower than 30% for 124 subjects (80%), with no clear tendency for over/under estimation. Differences higher than 30% have been analysed and explained. pubmed.ncbi.nlm.nih.gov

AI evidence extraction

Main findings

Residential ELF-MF exposure was calculated for 1124 subjects living close enough to high-voltage overhead lines that exposure could exceed 0.1 µT; 371/1124 had calculated exposure >0.1 µT and 123/1124 >0.4 µT (0.25% of the full study population). For 156 subjects with comparable measurement data after extrapolation, the difference between calculated and adjusted measured values was <30% for 124 (80%), with no clear tendency toward over- or under-estimation; larger differences were analyzed and explained.

Outcomes measured

• Calculated residential ELF magnetic field exposure (µT) relative to 0.1 µT and 0.4 µT thresholds
• Agreement between calculated exposures and adjusted measurements (percent difference; proportion within 30%)

Limitations

• Exposure calculations were performed only for a subset (1124) selected based on proximity sufficient to potentially exceed 0.1 µT.
• Measurement comparisons were available for a subset (comparison possible for 156 subjects), implying incomplete validation coverage.
• Measured values required extrapolation/adjustment to match calculation conditions, which may introduce uncertainty.

Suggested hubs

• occupational-exposure (0.05)
  Study concerns residential (not occupational) exposure; hub match is weak.

{
    "study_type": "exposure_assessment",
    "exposure": {
        "band": "ELF",
        "source": "high voltage overhead lines",
        "frequency_mhz": null,
        "sar_wkg": null,
        "duration": null
    },
    "population": "GEOCAP epidemiological study population in mainland France (paediatric leukaemia cases and controls; subset assessed for proximity to power lines)",
    "sample_size": 49174,
    "outcomes": [
        "Calculated residential ELF magnetic field exposure (µT) relative to 0.1 µT and 0.4 µT thresholds",
        "Agreement between calculated exposures and adjusted measurements (percent difference; proportion within 30%)"
    ],
    "main_findings": "Residential ELF-MF exposure was calculated for 1124 subjects living close enough to high-voltage overhead lines that exposure could exceed 0.1 µT; 371/1124 had calculated exposure >0.1 µT and 123/1124 >0.4 µT (0.25% of the full study population). For 156 subjects with comparable measurement data after extrapolation, the difference between calculated and adjusted measured values was <30% for 124 (80%), with no clear tendency toward over- or under-estimation; larger differences were analyzed and explained.",
    "effect_direction": "unclear",
    "limitations": [
        "Exposure calculations were performed only for a subset (1124) selected based on proximity sufficient to potentially exceed 0.1 µT.",
        "Measurement comparisons were available for a subset (comparison possible for 156 subjects), implying incomplete validation coverage.",
        "Measured values required extrapolation/adjustment to match calculation conditions, which may introduce uncertainty."
    ],
    "evidence_strength": "moderate",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "GEOCAP",
        "paediatric cancers",
        "leukaemia",
        "France",
        "residential exposure",
        "extremely low frequency magnetic field",
        "ELF-MF",
        "power frequency",
        "high voltage overhead lines",
        "63-400 kV",
        "exposure modelling",
        "measurement comparison",
        "0.1 µT",
        "0.4 µT"
    ],
    "suggested_hubs": [
        {
            "slug": "occupational-exposure",
            "weight": 0.05000000000000000277555756156289135105907917022705078125,
            "reason": "Study concerns residential (not occupational) exposure; hub match is weak."
        }
    ]
}

Comments

Log in to comment.

No comments yet.