Electromagnetic field exposures and childhood cancers in New Zealand.

Abstract

OBJECTIVES: To assess childhood cancer risks for electromagnetic field (EMF) exposures. METHODS: A case-control study was conducted in New Zealand. Cases (aged from zero to 14 years) were ascertained from national databases including the New Zealand Cancer Registry; 303 took part (participation rate, 88 percent). The 303 age- and gender-matched controls were selected randomly from birth records (participation, 69 percent). Mothers were interviewed about appliance exposures (all cases and controls), and 24-hour residential measurements of EMFs were made (leukemia cases and matched controls). RESULTS: For the various appliance exposures, there were some odds ratios (OR) above 1.0 and others below 1.0. For electric blanket use by the child before diagnosis, the adjusted ORs were: leukemia, 2.2 (95 percent confidence interval [CI] = 0.7-6.4); central nervous system cancers, ORs = 1.6 (CI = 0.4-7.1); and other solid cancers, OR = 2.4 (CI = 1.0-6.1). Leukemia risk was increased for the highest category of the mean measured bedroom magnetic field (> or = 0.2microT cf < 0.1 microT), with an adjusted OR of 15.5 (CI = 1.1-224). A gradient in OR with exposure was not shown (middle category: OR 1.4, CI = 0.3-7.6), and there was no association with exposure categorized into thirds based on controls' exposure. The adjusted OR for leukemia in relation to the measured daytime room magnetic field (> or = 0.2 microT cf < 0.1 microT) was 5.2 (CI = 0.9-30.8). CONCLUSIONS: This was a small study and multiple comparisons were made. The positive findings thus should be interpreted cautiously.

AI evidence extraction

Main findings

Across various appliance exposures, some odds ratios were above 1.0 and others below 1.0. For electric blanket use by the child before diagnosis, adjusted ORs were 2.2 (95% CI 0.7–6.4) for leukemia, 1.6 (0.4–7.1) for CNS cancers, and 2.4 (1.0–6.1) for other solid cancers. For leukemia, the highest category of mean measured bedroom magnetic field (≥0.2 µT vs <0.1 µT) had an adjusted OR of 15.5 (1.1–224), but no exposure gradient was shown and no association was seen when exposure was categorized into thirds based on controls; daytime room magnetic field (≥0.2 µT vs <0.1 µT) had an adjusted OR of 5.2 (0.9–30.8).

Outcomes measured

• Childhood cancers (leukemia, central nervous system cancers, other solid cancers)

Limitations

• Small study
• Multiple comparisons were made
• Wide confidence intervals for some estimates
• No exposure gradient shown for mean measured bedroom magnetic field categories
• Participation rates differed between cases (88%) and controls (69%)

Suggested hubs

• elf-magnetic-fields (0.9)
  Study includes measured residential magnetic fields in µT and relates them to childhood leukemia risk.
• childhood-leukemia (0.85)
  Reports leukemia-specific odds ratios for measured bedroom/daytime magnetic fields and appliance exposures.

{
    "study_type": "case_control",
    "exposure": {
        "band": "ELF",
        "source": "residential/appliances (including electric blankets)",
        "frequency_mhz": null,
        "sar_wkg": null,
        "duration": "24-hour residential measurements; appliance use before diagnosis (timing not further specified)"
    },
    "population": "Children aged 0–14 years in New Zealand (cases from national databases; controls from birth records)",
    "sample_size": 606,
    "outcomes": [
        "Childhood cancers (leukemia, central nervous system cancers, other solid cancers)"
    ],
    "main_findings": "Across various appliance exposures, some odds ratios were above 1.0 and others below 1.0. For electric blanket use by the child before diagnosis, adjusted ORs were 2.2 (95% CI 0.7–6.4) for leukemia, 1.6 (0.4–7.1) for CNS cancers, and 2.4 (1.0–6.1) for other solid cancers. For leukemia, the highest category of mean measured bedroom magnetic field (≥0.2 µT vs <0.1 µT) had an adjusted OR of 15.5 (1.1–224), but no exposure gradient was shown and no association was seen when exposure was categorized into thirds based on controls; daytime room magnetic field (≥0.2 µT vs <0.1 µT) had an adjusted OR of 5.2 (0.9–30.8).",
    "effect_direction": "mixed",
    "limitations": [
        "Small study",
        "Multiple comparisons were made",
        "Wide confidence intervals for some estimates",
        "No exposure gradient shown for mean measured bedroom magnetic field categories",
        "Participation rates differed between cases (88%) and controls (69%)"
    ],
    "evidence_strength": "low",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "childhood cancer",
        "leukemia",
        "central nervous system cancer",
        "case-control",
        "New Zealand",
        "electric blanket",
        "appliance exposure",
        "residential measurement",
        "magnetic field",
        "microtesla"
    ],
    "suggested_hubs": [
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            "slug": "elf-magnetic-fields",
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            "reason": "Study includes measured residential magnetic fields in µT and relates them to childhood leukemia risk."
        },
        {
            "slug": "childhood-leukemia",
            "weight": 0.84999999999999997779553950749686919152736663818359375,
            "reason": "Reports leukemia-specific odds ratios for measured bedroom/daytime magnetic fields and appliance exposures."
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}

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