Residential exposure to magnetic fields from high-voltage power lines and risk of childhood leukemia

Abstract

Residential exposure to magnetic fields from high-voltage power lines and risk of childhood leukemia Malagoli C, Malavolti M, Wise LA, Balboni E, Fabbi S, Teggi S, Palazzi G, Cellini M, Poli M, Zanichelli P, Notari B, Cherubini A, Vinceti M, Filippini T. Residential exposure to magnetic fields from high-voltage power lines and risk of childhood leukemia. Environ Res. 2023 Jun 2:116320. doi: 10.1016/j.envres.2023.116320. Highlights • The exact relation between magnetic fields and childhood leukemia risk is still to be elucidated. • Residence very close to power lines was associated with greater childhood leukemia risk. • The association between residential proximity to power lines and leukemia risk was non-linear. Abstract Background: Several studies have suggested an excess risk of leukemia among children living close to high- voltage power lines and exposed to magnetic fields. However, not all studies have yielded consistent results, and many studies may have been susceptible to confounding and exposure misclassification. Methods: We conducted a case-control study to investigate the risk of leukemia associated with magnetic field exposure from high-voltage power lines. Eligible participants were children aged 0-15 years residing in the Northern Italian provinces of Modena and Reggio Emilia. We included all 182 registry-identified childhood leukemia cases diagnosed in 1998-2019, and 726 age-, sex- and province-matched population controls. We assessed exposure by calculating distance from house to nearest power line and magnetic field intensity modelling at the subjects' residence. We used conditional logistic regression models to estimate odds ratios (ORs) and 95% confidence intervals (CIs), with adjustment for potential confounders (distance from nearest petrol station and fuel supply within the 1000 m-buffer, traffic-related particulate and benzene concentrations, presence of indoor transformers, percentage of urban area and arable crops). Results: In multivariable analyses, the OR comparing children living <100 m from high-voltage power-lines with children living ≥400 m from power-lines was 2.0 (95% CI 0.8-5.0). Results did not differ substantially by age at disease diagnosis, disease subtype, or when exposure was based on modeled magnetic field intensity, though estimates were imprecise. Spline regression analysis showed an excess risk for both overall leukemia and acute lymphoblastic leukemia among children with residential distances <100 m from power lines, with a monotonic inverse association below this cutpoint. Conclusions: In this Italian population, close proximity to high-voltage power lines was associated with an excess risk of childhood leukemia, particularly among the youngest children. pubmed.ncbi.nlm.nih.gov Excerpts Compared with children living ≥400 m from a power line, ORs for leukemia among children residing <100 m from the nearest power line were 2.1 (95% CI: 0.9–5.2) in the crude analysis and ORs of 2.0 (95% CI: 0.8–5.0) in multivariable model. Restricting the analysis to the ALL subtype, these respective ORs were 2.3 (95% CI: 0.9–6.1) and 2.2 (95% CI: 0.8–6.0) (Table 2).... In age-stratified analyses, ORs for overall leukemia were slightly stronger among younger children, living <100 m (vs. ≥400 m) from a power line, with ORs of 2.4 (95% CI: 0.4–14.6) among children aged <5 years and 1.8 (95% CI: 0.6–5.4) among children aged >5 years in the fully-adjusted model (Table 2). Conversely, for the ALL subtype, the OR was slightly stronger among older children (≥5 years: multivariable OR = 2.0, 95% CI: 0.6–6.4) than among younger children (<5 years: multivariable OR = 1.8, 95% CI: 0.2–20.0).... In the dose-response spline model, we observed a strong though imprecise association between distance from power lines and an excess risk of leukemia among children residing within close proximity to the lines, i.e. <100 m, in both crude and adjusted analysis, while there was no such indication at distance greater than 150 m (Fig. 1). Adjustment for potential confounders had little influence on this pattern (Fig. 1B). We found comparable trends when ALL is considered only (Supplementary Figure S1).... Over the last four decades, residential exposure to extremely low frequency magnetic fields, including those generated by power lines, has been associated with childhood leukemia in several epidemiological studies, though there have been some inconsistencies in results, likely owing to small sample sizes, selection and information biases, and residual confounding ... In conclusion, in this Italian population, residence within 100 m of high-voltage power lines was associated with an increased risk of childhood leukemia. These results showed a clear dose-response relation below that cutpoint, though the results were imprecise. Our findings are generally consistent with findings obtained in several studies worldwide.

AI evidence extraction

Main findings

In multivariable analyses, children living <100 m from high-voltage power lines had higher odds of leukemia compared with those living ≥400 m away (OR 2.0, 95% CI 0.8–5.0). Spline models suggested excess risk for overall leukemia and ALL at distances <100 m, with no indication of increased risk at distances >150 m; results were described as imprecise and were similar when using modeled magnetic field intensity.

Outcomes measured

• Childhood leukemia
• Acute lymphoblastic leukemia (ALL)

Limitations

• Estimates described as imprecise (wide confidence intervals)
• Potential for confounding and exposure misclassification noted in background (and addressed via adjustment)
• Small numbers in some stratified analyses (implied by very wide CIs)

Suggested hubs

• power-lines-elf (0.95)
  Case-control study of residential proximity to high-voltage power lines / ELF magnetic fields and childhood leukemia risk.

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    "study_type": "case_control",
    "exposure": {
        "band": "ELF",
        "source": "high-voltage power lines (residential proximity)",
        "frequency_mhz": null,
        "sar_wkg": null,
        "duration": null
    },
    "population": "Children aged 0–15 years residing in the Northern Italian provinces of Modena and Reggio Emilia",
    "sample_size": 908,
    "outcomes": [
        "Childhood leukemia",
        "Acute lymphoblastic leukemia (ALL)"
    ],
    "main_findings": "In multivariable analyses, children living <100 m from high-voltage power lines had higher odds of leukemia compared with those living ≥400 m away (OR 2.0, 95% CI 0.8–5.0). Spline models suggested excess risk for overall leukemia and ALL at distances <100 m, with no indication of increased risk at distances >150 m; results were described as imprecise and were similar when using modeled magnetic field intensity.",
    "effect_direction": "harm",
    "limitations": [
        "Estimates described as imprecise (wide confidence intervals)",
        "Potential for confounding and exposure misclassification noted in background (and addressed via adjustment)",
        "Small numbers in some stratified analyses (implied by very wide CIs)"
    ],
    "evidence_strength": "low",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "childhood leukemia",
        "acute lymphoblastic leukemia",
        "case-control",
        "residential exposure",
        "high-voltage power lines",
        "magnetic fields",
        "distance to power line",
        "modeled magnetic field intensity",
        "Italy",
        "ELF"
    ],
    "suggested_hubs": [
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            "reason": "Case-control study of residential proximity to high-voltage power lines / ELF magnetic fields and childhood leukemia risk."
        }
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}

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