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The relationship between residential magnetic fields and contact voltage: a pooled analysis
1Electric Power Research Institute, Palo Alto, California 94304, USA. rkavet@epri.com
Radiation Research
|October 13, 2011
Summary
Residential contact currents, not magnetic fields, may increase childhood leukemia risk. This study found a strong association between contact voltage and magnetic fields, suggesting contact current could explain the link to leukemia.
Area of Science:
- Environmental Health
- Epidemiology
- Pediatric Oncology
Background:
- Residential exposure to contact currents, particularly through water fixtures and conductive drainpipes, is hypothesized to be linked to childhood leukemia risk.
- The Northern California Childhood Leukemia Study (NCCLS) is unique in investigating contact current as a potential confounder in the association between residential magnetic fields and childhood leukemia.
Purpose of the Study:
- To analyze the relationship between residential magnetic fields and contact voltage.
- To determine if contact current exposure confounds the association between magnetic fields and childhood leukemia.
Main Methods:
- Combined NCCLS data (500+ residences) with previous contact voltage measurements for a total of 702 residences.
- Analyzed Spearman correlation between magnetic field and contact voltage.
- Categorized data into tertiles using established cutpoints (magnetic field: 0.3 μT; contact voltage: 60 mV) for exposure odds ratio (EOR) analysis.
Main Results:
- A significant positive Spearman correlation (0.29, P < 0.0001) was found between magnetic fields and contact voltage.
- Contact voltage was strongly associated with magnetic fields (EOR 15.1, 95% CI 3.6-61).
- A significant positive trend in risk was observed across increasing magnetic field strata (EOR 4.2 per stratum, 95% CI 2.4-7.4).
Conclusions:
- The observed associations between contact voltage and magnetic fields are substantial.
- Contact current exposure may be the driving factor behind the previously reported association between residential magnetic fields and childhood leukemia.
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