Nighttime exposure to electromagnetic fields and childhood leukemia: an extended pooled analysis.

American journal of epidemiology · 2007 · Mixed · Low evidence

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MixedLow evidencePaper 5068

Study snapshot

PublicationAmerican journal of epidemiology · 2007

Study typepolicy

Reported directionMixed

Evidence ratingLow

Abstract

It has been hypothesized that nighttime bedroom measurements of extremely low frequency electromagnetic fields (ELF EMF) may represent a more accurate reflection of exposure and have greater biologic relevance than previously used 24-/48-hour measurements. Accordingly, the authors extended a pooled analysis of case-control studies on ELF EMF exposure and risk of childhood leukemia to examine nighttime residential exposures. Data from four countries (Canada, Germany, the United Kingdom, and the United States) were included in the analysis, comprising 1,842 children diagnosed with leukemia and 3,099 controls (diagnosis dates ranged from 1988 to 1996). The odds ratios for nighttime ELF EMF exposure for categories of 0.1-<0.2 microT, 0.2-<0.4 microT, and >or=0.4 microT as compared with <0.1 microT were 1.11 (95% confidence interval (CI): 0.91, 1.36), 1.37 (95% CI: 0.99, 1.90), and 1.93 (95% CI: 1.11, 3.35), respectively. The fact that these estimates were similar to those derived using 24-/48-hour geometric mean values (odds ratios of 1.09, 1.20, and 1.98, respectively) indicates that the nighttime component cannot, on its own, account for the pattern observed. These results do not support the hypotheses that nighttime measures are more appropriate; hence, the observed association between ELF EMF and childhood leukemia still lacks a plausible explanation.

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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 typepolicy

Effect directionmixed

PopulationChildren (cases diagnosed with leukemia) and controls from Canada, Germany, the United Kingdom, and the United States (diagnosis dates 1988–1996)

Sample size4941

ExposureELF · nighttime; compared with 24-/48-hour measurements

Evidence strengthLowConfidence: 74% · Peer reviewed: yes

Main findings

In a pooled analysis of case-control studies, nighttime bedroom ELF EMF exposure showed increasing odds ratios for childhood leukemia across exposure categories compared with <0.1 microT: 1.11 (0.91–1.36) for 0.1–<0.2 microT, 1.37 (0.99–1.90) for 0.2–<0.4 microT, and 1.93 (1.11–3.35) for ≥0.4 microT. These estimates were similar to those using 24-/48-hour geometric mean values, and the authors concluded nighttime measures were not more appropriate and do not explain the observed association.

Outcomes measured

childhood leukemia

View raw extracted JSON

{
  "study_type": "policy",
  "exposure": {
    "band": "ELF",
    "source": "residential (bedroom nighttime measurements)",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": "nighttime; compared with 24-/48-hour measurements"
  },
  "population": "Children (cases diagnosed with leukemia) and controls from Canada, Germany, the United Kingdom, and the United States (diagnosis dates 1988–1996)",
  "sample_size": 4941,
  "outcomes": [
    "childhood leukemia"
  ],
  "main_findings": "In a pooled analysis of case-control studies, nighttime bedroom ELF EMF exposure showed increasing odds ratios for childhood leukemia across exposure categories compared with <0.1 microT: 1.11 (0.91–1.36) for 0.1–<0.2 microT, 1.37 (0.99–1.90) for 0.2–<0.4 microT, and 1.93 (1.11–3.35) for ≥0.4 microT. These estimates were similar to those using 24-/48-hour geometric mean values, and the authors concluded nighttime measures were not more appropriate and do not explain the observed association.",
  "effect_direction": "mixed",
  "limitations": [],
  "evidence_strength": "low",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "extremely low frequency",
    "ELF EMF",
    "nighttime exposure",
    "bedroom measurements",
    "residential exposure",
    "pooled analysis",
    "case-control",
    "childhood leukemia",
    "microtesla"
  ],
  "suggested_hubs": [
    {
      "slug": "who-icnirp",
      "weight": 0.35,
      "reason": "Addresses ELF EMF exposure and childhood leukemia risk, a topic commonly evaluated in major health risk assessments."
    }
  ]
}

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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: 10.1093/aje/kwm080
PubMed: 17485729

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