Residential exposure to magnetic field due to high-voltage power lines and childhood leukemia risk in mainland France - GEOCAP case-control study, 2002-2010

Abstract

Background: Environmental exposure to extremely low frequency magnetic fields (ELF-MF) is suspected of being a risk factor of childhood acute leukemia (AL) and classified as possible carcinogen. Results of recent epidemiological studies remain however heterogeneous.

Objective: The present study aimed to evaluate AL risk in children exposed to ELF-MF by living close to high-voltage overhead power lines (HVOL) in France.

Methods: We included 4117 AL cases under the age of 15 diagnosed in 2002-2010 and 44,838 contemporary controls representative of the French pediatric population, drawn from the national registry-based GEOCAP study. The distance between the geocoded address of residence and the closest 63-400 kV HVOL, and the closest 225-400 kV HVOL, were evaluated. ELF-MF exposure was also calculated at the geocoded addresses considering the characteristics of the neighboring HVOLs. Logistic regression models adjusted for age were used to estimate odds-ratios (OR) and 95 % confidence intervals. Sensitivity analyses were carried out to account for geocoding error and potential confounders.

Results: 0.7 % of the controls lived within 50 m of HVOL and 0.3 % were exposed to more than 0.3 μT. Living within 50 m of HVOL was associated with an increased risk of AL for children under 5 (OR = 1.6 (1.0-2.7)), an association more marked when restricting to the high-quality geocoded addresses (OR = 3.2 (1.3-7.9)). ELF-MF was not associated with AL risk (≥0.3 μT, OR = 0.6 (0.3-1.3)). The results remained stable in all the sensitivity analyses.

Conclusion: Our study brings new evidence that ELF-MF are probably not associated with AL risk, and cannot explain an association with distance to HVOL.