Residential exposure to extremely low-frequency magnetic fields and risk of childhood leukaemia, CNS tumour and lymphoma in Denmark

Abstract

Background: We previously reported that children exposed to elevated extremely low-frequency magnetic fields (ELF-MF) had a five to six times higher risk of leukaemia, central nervous system (CNS) tumour and malignant lymphoma. Here we extend the study from 1968 to 1986 through 2003. Methods: We included 3277 children with leukaemia, CNS tumour or malignant lymphoma during 1968-2003 recorded in the Danish Cancer Registry and 9129 controls randomly selected from the Danish childhood population. ELF-MF from 50 to 400 kV facilities were calculated at the residences. Results: For recently diagnosed cases (1987-2003), the relative risk (RR) was 0.88 (95% confidence interval (CI): 0.32-2.42), while for the total period (1968-2003) it was 1.63 (95% CI: 0.77-3.46) for leukaemia, CNS tumour and malignant lymphoma combined for exposures ⩾0.4 μT compared with <0.1 μT. These results were based on five cases (recent period) and 11 cases (total period) in the highest exposure group. Conclusions: We did not confirm the previous finding of a five- to six-fold higher risk for leukaemia, CNS tumour and malignant lymphoma when including data from the more recent time period. For the total time period, the results for childhood leukaemia were in line with large pooled analyses showing RRs between 1.5 and 2.

AI evidence extraction

Main findings

In a Danish case-control study (1968-2003) estimating residential ELF-MF from 50–400 kV facilities, the RR for leukaemia/CNS tumour/lymphoma combined at ≥0.4 μT vs <0.1 μT was 0.88 (95% CI 0.32–2.42) for 1987–2003 and 1.63 (95% CI 0.77–3.46) for 1968–2003. The highest exposure category included 5 cases (1987–2003) and 11 cases (1968–2003). The authors report they did not confirm a previously reported 5–6-fold higher risk when including the more recent period.

Outcomes measured

• Childhood leukaemia
• Childhood CNS tumour
• Childhood malignant lymphoma

Limitations

• Very small number of cases in the highest exposure group (5 in 1987–2003; 11 in 1968–2003)
• Confidence intervals are wide for the highest exposure comparison
• Exposure was calculated (modeled) at residences from 50–400 kV facilities; other ELF-MF sources are not described in the abstract

Suggested hubs

• elf-powerlines (0.9)
  Residential ELF-MF exposure calculated from 50–400 kV facilities (power transmission).

{
    "study_type": "case_control",
    "exposure": {
        "band": "ELF",
        "source": "residential proximity to high-voltage facilities",
        "frequency_mhz": null,
        "sar_wkg": null,
        "duration": "1968-2003 (recent period 1987-2003)"
    },
    "population": "Children in Denmark",
    "sample_size": 12406,
    "outcomes": [
        "Childhood leukaemia",
        "Childhood CNS tumour",
        "Childhood malignant lymphoma"
    ],
    "main_findings": "In a Danish case-control study (1968-2003) estimating residential ELF-MF from 50–400 kV facilities, the RR for leukaemia/CNS tumour/lymphoma combined at ≥0.4 μT vs <0.1 μT was 0.88 (95% CI 0.32–2.42) for 1987–2003 and 1.63 (95% CI 0.77–3.46) for 1968–2003. The highest exposure category included 5 cases (1987–2003) and 11 cases (1968–2003). The authors report they did not confirm a previously reported 5–6-fold higher risk when including the more recent period.",
    "effect_direction": "mixed",
    "limitations": [
        "Very small number of cases in the highest exposure group (5 in 1987–2003; 11 in 1968–2003)",
        "Confidence intervals are wide for the highest exposure comparison",
        "Exposure was calculated (modeled) at residences from 50–400 kV facilities; other ELF-MF sources are not described in the abstract"
    ],
    "evidence_strength": "low",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "extremely low-frequency magnetic fields",
        "ELF-MF",
        "residential exposure",
        "high-voltage facilities",
        "childhood leukaemia",
        "CNS tumour",
        "malignant lymphoma",
        "Denmark",
        "case-control"
    ],
    "suggested_hubs": [
        {
            "slug": "elf-powerlines",
            "weight": 0.90000000000000002220446049250313080847263336181640625,
            "reason": "Residential ELF-MF exposure calculated from 50–400 kV facilities (power transmission)."
        }
    ]
}

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