Electromagnetic field exposures and childhood cancers in New Zealand.

Cancer causes & control : CCC · 1998 · Mixed · Low evidence

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MixedLow evidencePaper 5386

Study snapshot

PublicationCancer causes & control : CCC · 1998

Study typecase_control

Reported directionMixed

Evidence ratingLow

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.

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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

PopulationChildren aged 0–14 years in New Zealand (cases from national databases; controls from birth records)

Sample size606

ExposureELF · 24-hour residential measurements; appliance use before diagnosis (timing not further specified)

Evidence strengthLowConfidence: 78% · Peer reviewed: yes

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%)

View raw extracted JSON

{
  "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": 0.78,
  "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": [
    {
      "slug": "elf-magnetic-fields",
      "weight": 0.9,
      "reason": "Study includes measured residential magnetic fields in µT and relates them to childhood leukemia risk."
    },
    {
      "slug": "childhood-leukemia",
      "weight": 0.85,
      "reason": "Reports leukemia-specific odds ratios for measured bedroom/daytime magnetic fields and appliance exposures."
    }
  ]
}

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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: 10.1023/a:1008825220759
PubMed: 9684710

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