Extremely low frequency magnetic fields in residences in Germany. Distribution of measurements, comparison of two methods for assessing exposure, and predictors for the occurrence of magnetic fields above background level.

Radiation and environmental biophysics · 2000 · Unclear · Moderate evidence

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UnclearModerate evidencePaper 3982

Study snapshot

PublicationRadiation and environmental biophysics · 2000

Study typeexposure_assessment

Reported directionUnclear

Evidence ratingModerate

Abstract

We examined the results of 1,835 magnetic field measurements in German residences conducted between November 1997 and September 1999. The measurements were part of an epidemiological study on the relationship between magnetic fields and childhood leukemia. We performed a fixed-location measurement of the magnetic field at 50 Hz and 16 2/3 Hz (frequency of the German railway system) over 24 h in the child's bedroom in the residence of each study participant. In addition, we conducted a second 24 h-measurement in the living room at 50 Hz, and spot measurements while walking through all rooms of the respective dwelling. Median 50 Hz magnetic fields above 0.2 muT were found to be infrequent in Germany (only 1.4% of all residences). Fields produced by high-voltage power lines (123-420 kV) were lower than expected: the median magnetic field was above 0.2 muT in only 8 (32.0%) of 25 residences located 50 m or closer to a high-voltage power line indicating that power lines in Germany are usually run well below the maximum power load. We found that magnetic fields were correlated with the type of residence and higher magnetic fields were measured in apartment buildings. There was also some evidence for a positive correlation between magnetic fields and traffic density and an inverse association between magnetic fields and family net income. The 24 h-magnetic field measurements correlated well with the spot measurements (r>0.7). However, when dichotomized with a cut-off point of 0.2 muT, there was only a poor agreement between the two measurement methods. A loss of the strength of the association after categorization was also observed when comparing the arithmetic mean and median of the same 24 h-measurement. In summary, these analyses give a valuable overview of magnetic field distributions in German residences.

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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 typeexposure_assessment

Effect directionunclear

PopulationGerman residences (child participants' homes in an epidemiological study on magnetic fields and childhood leukemia)

Sample size1835

ExposureELF · 24 h fixed-location measurements (bedroom; plus living room at 50 Hz) and spot measurements through dwelling

Evidence strengthModerateConfidence: 78% · Peer reviewed: yes

Main findings

Across 1,835 measurements in German residences (1997–1999), median 50 Hz magnetic fields >0.2 µT were infrequent (1.4% of residences). Among 25 residences within 50 m of high-voltage power lines (123–420 kV), the median field exceeded 0.2 µT in 8 (32%). 24 h measurements correlated well with spot measurements (r>0.7), but agreement was poor when dichotomizing at 0.2 µT; apartment buildings had higher measured fields, with some evidence of positive correlation with traffic density and inverse association with family net income.

Outcomes measured

Residential magnetic field levels at 50 Hz and 16 2/3 Hz
Proportion of residences with median 50 Hz magnetic fields >0.2 µT
Magnetic fields near high-voltage power lines (123–420 kV)
Correlation/agreement between 24 h measurements and spot measurements
Predictors/correlates of higher residential magnetic fields (type of residence, traffic density, family net income)

Limitations

Agreement between measurement methods was poor after dichotomizing at 0.2 µT, suggesting categorization may reduce information/association strength
Abstract does not report detailed statistical estimates for predictors (e.g., effect sizes, confidence intervals)
Sampling frame is residences of study participants in a childhood leukemia epidemiological study; representativeness for all German residences is not stated

View raw extracted JSON

{
  "study_type": "exposure_assessment",
  "exposure": {
    "band": "ELF",
    "source": "residential",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": "24 h fixed-location measurements (bedroom; plus living room at 50 Hz) and spot measurements through dwelling"
  },
  "population": "German residences (child participants' homes in an epidemiological study on magnetic fields and childhood leukemia)",
  "sample_size": 1835,
  "outcomes": [
    "Residential magnetic field levels at 50 Hz and 16 2/3 Hz",
    "Proportion of residences with median 50 Hz magnetic fields >0.2 µT",
    "Magnetic fields near high-voltage power lines (123–420 kV)",
    "Correlation/agreement between 24 h measurements and spot measurements",
    "Predictors/correlates of higher residential magnetic fields (type of residence, traffic density, family net income)"
  ],
  "main_findings": "Across 1,835 measurements in German residences (1997–1999), median 50 Hz magnetic fields >0.2 µT were infrequent (1.4% of residences). Among 25 residences within 50 m of high-voltage power lines (123–420 kV), the median field exceeded 0.2 µT in 8 (32%). 24 h measurements correlated well with spot measurements (r>0.7), but agreement was poor when dichotomizing at 0.2 µT; apartment buildings had higher measured fields, with some evidence of positive correlation with traffic density and inverse association with family net income.",
  "effect_direction": "unclear",
  "limitations": [
    "Agreement between measurement methods was poor after dichotomizing at 0.2 µT, suggesting categorization may reduce information/association strength",
    "Abstract does not report detailed statistical estimates for predictors (e.g., effect sizes, confidence intervals)",
    "Sampling frame is residences of study participants in a childhood leukemia epidemiological study; representativeness for all German residences is not stated"
  ],
  "evidence_strength": "moderate",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "extremely low frequency",
    "ELF",
    "magnetic fields",
    "residential exposure",
    "Germany",
    "50 Hz",
    "16 2/3 Hz",
    "railway frequency",
    "high-voltage power lines",
    "spot measurements",
    "24-hour measurement",
    "exposure assessment",
    "childhood leukemia study"
  ],
  "suggested_hubs": [
    {
      "slug": "occupational-exposure",
      "weight": 0,
      "reason": null
    }
  ]
}

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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: 10.1007/s004110000068
PubMed: 11200967

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