Sleep quality and general health status of employees exposed to extremely low frequency magnetic fields in a petrochemical complex

J Environ Health Sci Eng · 2014 · Mixed · Low evidence

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MixedLow evidencePaper 2750

Study snapshot

PublicationJ Environ Health Sci Eng · 2014

Study typecross_sectional

Reported directionMixed

Evidence ratingLow

Abstract

Background: Advances in science and technology of electrical equipment, despite increasing human welfare in everyday life, have increased the number of people exposed to Electro-Magnetic Fields (EMFs). Because of possible adverse effects on the health of exposed individuals, the EMFs have being the center of attention. This study was performed to determine possible correlation between Extremely Low Frequency Electro-Magnetic Fields (ELF EMFs) and sleep quality and public health of those working in substation units of a petrochemical complex in southern Iran. Materials and method: To begin with, magnetic flux density was measured at different parts of a Control Building and two substations in accordance with IEEE std 644-1994. Subsequently, the questionnaires "Pittsburgh Sleep Quality Index" (PSQI) and "General Health Quality (GHQ)" were used to investigate relationship between ELF exposure level and sleep quality and public health, respectively. Both questionnaires were placed at disposal of a total number of 40 workers at the complex. The filled out questionnaires were analyzed by T-test, Duncan and the Chi-square tests. Results: The obtained results revealed that 28% of those in case group suffered from poor health status and 61% were diagnosed with a sleep disorder. However, all members in control group were in good health condition and only 4.5% of them had undesirable sleep quality. Conclusion: In spite of a significant difference between the case and control groups in terms of sleep quality and general health, no significant relationship was found between the exposure level and sleep quality and general health. It is worth noting that the measured EMF values were lower than the standard limits recommended by American Conference of Industrial Hygienists (ACGIH). However, given the uncertainties about the pathogenic effects caused by exposure to ELF EMFs, further epidemiological studies and periodic testing of personnel working in high voltage substations are of utmost importance.

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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 typecross_sectional

Effect directionmixed

PopulationWorkers in substation units of a petrochemical complex in southern Iran (case and control groups)

Sample size40

ExposureELF

Evidence strengthLowConfidence: 74% · Peer reviewed: yes

Main findings

Case vs control groups differed significantly in sleep quality and general health: 61% of the case group were diagnosed with a sleep disorder and 28% had poor health status, while the control group were all in good health and 4.5% had undesirable sleep quality. However, no significant relationship was found between measured ELF exposure level and sleep quality or general health. Measured EMF values were below ACGIH recommended standard limits.

Outcomes measured

Sleep quality (Pittsburgh Sleep Quality Index; PSQI)
General health status (General Health Questionnaire; GHQ)

Limitations

Small sample size (40 workers)
Cross-sectional design (correlation/association only)
Exposure characterization details (e.g., frequency, individual exposure duration) not reported in abstract
Outcomes based on self-report questionnaires

View raw extracted JSON

{
  "study_type": "cross_sectional",
  "exposure": {
    "band": "ELF",
    "source": "occupational (substation units in a petrochemical complex)",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": null
  },
  "population": "Workers in substation units of a petrochemical complex in southern Iran (case and control groups)",
  "sample_size": 40,
  "outcomes": [
    "Sleep quality (Pittsburgh Sleep Quality Index; PSQI)",
    "General health status (General Health Questionnaire; GHQ)"
  ],
  "main_findings": "Case vs control groups differed significantly in sleep quality and general health: 61% of the case group were diagnosed with a sleep disorder and 28% had poor health status, while the control group were all in good health and 4.5% had undesirable sleep quality. However, no significant relationship was found between measured ELF exposure level and sleep quality or general health. Measured EMF values were below ACGIH recommended standard limits.",
  "effect_direction": "mixed",
  "limitations": [
    "Small sample size (40 workers)",
    "Cross-sectional design (correlation/association only)",
    "Exposure characterization details (e.g., frequency, individual exposure duration) not reported in abstract",
    "Outcomes based on self-report questionnaires"
  ],
  "evidence_strength": "low",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "extremely low frequency",
    "ELF EMF",
    "magnetic flux density",
    "occupational exposure",
    "substation",
    "petrochemical complex",
    "sleep quality",
    "PSQI",
    "general health",
    "GHQ"
  ],
  "suggested_hubs": [
    {
      "slug": "occupational-exposure",
      "weight": 0.9,
      "reason": "Study of employees working in substations with measured ELF magnetic fields."
    }
  ]
}

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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: 10.1186/2052-336x-12-78
PubMed: 24904752

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