Electric and magnetic field exposure and brain cancer: a review.

A number of epidemiologic studies have investigated exposure to electric and magnetic fields as a possible risk factor for brain cancer. Studies of residential exposure and childhood brain tumors have produced inconsistent results, regardless of the exposure metrics used; this outcome holds for both current and past estimates of magnetic fields, whether based on wire codes, distance, or measured or calculated fields. Most recent studies provide little evidence of an association. Studies examining use of appliances by children or by their mothers during pregnancy have also found an inconsistent pattern of risk, and recent studies of parental occupational exposure and childhood brain tumors suggest a lack of an association. Methodological issues may weaken these conclusions. In adults, residential studies have found little or no association between electric and magnetic field exposure and brain cancer. However, meta-analysis of occupational studies indicates a slightly higher risk for electrical workers. A comparative analysis of major studies of electric utility workers also suggests a small increase in brain cancer risk. Of note in these analyses are large exposure misclassifications and the lack of a clear dose-response relationship in most individual studies.