Residential magnetic fields exposure and childhood leukemia: a population-based case–control study in California
Studies have reported an increased risk of childhood leukemia associated with exposure to magnetic fields. We conducted a large records-based case–control study of childhood leukemia risk and exposure to magnetic fields from power lines in California.
The study included 5,788 childhood leukemia cases (born in and diagnosed in California 1986–2008) matched to population-based controls on age and sex. We calculated magnetic fields at birth addresses using geographic information systems, aerial imagery, historical information on load and phasing, and site visits.
Based on unconditional logistic regression controlling for age, sex, race/ethnicity, and socioeconomic status using subjects geocoded to a basic standard of accuracy, we report a slight risk deficit in two intermediate exposure groups and a small excess risk in the highest exposure group (odds ratio of 1.50 (95% confidence interval [0.70, 3.23])). Subgroup and sensitivity analyses as well as matched analyses gave similar results. All estimates had wide confidence intervals.
Our large, statewide, record-based case–control study of childhood leukemia in California does not in itself provide clear evidence of risk associated with greater exposure to magnetic fields from power lines, but could be viewed as consistent with previous findings of increased risk.
KeywordsChildhood leukemia Case–control study EMF Magnetic fields GIS
The California Power Line Study is funded by the Electric Power Research Institute. Crespi was also partially support by National Institutes of Health CA 16042. The study was approved by University of California, Los Angeles (UCLA) Office for the Protection of Research Subjects, University of Southern California (USC) Institutional Review Board, and California Committee for the Protection of Human Subjects (CPHS). We are extremely grateful to Michael Herz of Pacific Gas and Electric Company, Glenn Sias and Phil Hung from Southern California Edison, Marilyn Dulich of San Diego Gas and Electric Company, Josephine Gonzalez of Los Angeles Department of Water and Power, and other employees of these utilities who contributed generously of their time and provided key data.
Compliance with ethical standards
Conflicts of interest
The authors declare no conflicts of interest.
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