[Cancer mortality among electricity utility workers in a the state of Sao Paulo, Brazil].

Abstract

A number of epidemiologic studies have observed an association between exposure to 50-60 Hz electromagnetic fields and the development of specific types of cancer. In Brazil, a preliminary report from a study of electricity facility workers in Rio de Janeiro (RJ) has mentioned relatively similar results. An exploratory analysis of death certificates obtained from a sample of electricity workers in S. Paulo was made. Data was analysed by using the Proportional Mortality Ratio (PMR) and the Proportional Cancer Mortality Ratio (PCMR). A slightly elevated all-sites cancer mortality was observed among these workers (PMR 1.11; 95% CI 0.91-1.35). Site specific analysis has shown a statistically significant higher mortality of laryngeal cancer (PCMR 2.04; 95% CI 1.05-4.20). An excess of deaths was also seen for cancers of the buccal cavity/pharynx, prostate, bladder, brain and Hodgkin's disease, although the results lacked statistical significance. When analysed by categories of estimated exposure to magnetic fields, an excess of deaths from bladder cancer (PCMR 4.17; 95% CI 1.35-9.72), neoplasms of the brain (PCMR 7.7; 95% CI 1.02-9.65) and Hodgkin's disease (PCMR 5.55; 95% CI 1.14-16.21) was observed in the group with probably higher exposure to EMF. A comparison of cancer mortality between these workers and petrochemical employees has shown a higher PCMR for larynx tumours (PCMR 3.51; 95% CI 3.02-15.51) and bladder cancer (PCMR 7.53; 95% CI 3.02-15.51). For brain tumours, however, a PCMR of 0.74 (95% CI 0.27-1.61) was noted. Although restrictions related to sample size in the study and the lack of information about known confounders must be considered, the results of this study do not fully disagree with others previously mentioned in the literature.

AI evidence extraction

Main findings

Using proportional mortality analyses of death certificates, all-sites cancer mortality was slightly elevated (PMR 1.11; 95% CI 0.91–1.35). Laryngeal cancer mortality was statistically significantly higher overall (PCMR 2.04; 95% CI 1.05–4.20). In the group with probably higher estimated magnetic-field exposure, excess deaths were reported for bladder cancer (PCMR 4.17; 95% CI 1.35–9.72), brain neoplasms (PCMR 7.7; 95% CI 1.02–9.65), and Hodgkin's disease (PCMR 5.55; 95% CI 1.14–16.21).

Outcomes measured

• All-sites cancer mortality
• Laryngeal cancer mortality
• Buccal cavity/pharynx cancer mortality
• Prostate cancer mortality
• Bladder cancer mortality
• Brain neoplasm mortality
• Hodgkin's disease mortality

Limitations

• Exploratory analysis based on death certificates
• Sample size limitations noted by authors
• Lack of information on known confounders
• Exposure based on categories of estimated magnetic-field exposure (details not provided)
• Uses PMR/PCMR (proportional mortality) rather than incidence or full cohort risk estimates

Suggested hubs

• occupational-exposure (0.9)
  Study evaluates cancer mortality in electricity utility workers with estimated magnetic-field exposure categories.

{
    "study_type": "cohort",
    "exposure": {
        "band": "ELF",
        "source": "occupational",
        "frequency_mhz": null,
        "sar_wkg": null,
        "duration": null
    },
    "population": "Electricity utility workers in the state of Sao Paulo, Brazil (death certificate sample)",
    "sample_size": null,
    "outcomes": [
        "All-sites cancer mortality",
        "Laryngeal cancer mortality",
        "Buccal cavity/pharynx cancer mortality",
        "Prostate cancer mortality",
        "Bladder cancer mortality",
        "Brain neoplasm mortality",
        "Hodgkin's disease mortality"
    ],
    "main_findings": "Using proportional mortality analyses of death certificates, all-sites cancer mortality was slightly elevated (PMR 1.11; 95% CI 0.91–1.35). Laryngeal cancer mortality was statistically significantly higher overall (PCMR 2.04; 95% CI 1.05–4.20). In the group with probably higher estimated magnetic-field exposure, excess deaths were reported for bladder cancer (PCMR 4.17; 95% CI 1.35–9.72), brain neoplasms (PCMR 7.7; 95% CI 1.02–9.65), and Hodgkin's disease (PCMR 5.55; 95% CI 1.14–16.21).",
    "effect_direction": "mixed",
    "limitations": [
        "Exploratory analysis based on death certificates",
        "Sample size limitations noted by authors",
        "Lack of information on known confounders",
        "Exposure based on categories of estimated magnetic-field exposure (details not provided)",
        "Uses PMR/PCMR (proportional mortality) rather than incidence or full cohort risk estimates"
    ],
    "evidence_strength": "very_low",
    "confidence": 0.7399999999999999911182158029987476766109466552734375,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "50-60 Hz",
        "extremely low frequency",
        "ELF",
        "magnetic fields",
        "occupational exposure",
        "electricity utility workers",
        "proportional mortality ratio",
        "PMR",
        "PCMR",
        "cancer mortality",
        "laryngeal cancer",
        "bladder cancer",
        "brain tumors",
        "Hodgkin disease",
        "Brazil"
    ],
    "suggested_hubs": [
        {
            "slug": "occupational-exposure",
            "weight": 0.90000000000000002220446049250313080847263336181640625,
            "reason": "Study evaluates cancer mortality in electricity utility workers with estimated magnetic-field exposure categories."
        }
    ]
}

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