Brain cancer and leukemia and exposure to power-frequency (50- to 60-Hz) electric and magnetic fields.

Abstract

Concern about a possible association between cancer and electric and magnetic fields created by the generation and use of electricity first surfaced in response to the study of childhood cancer in Denver, Colorado, by Wertheimer and Leeper (1). Since then, nearly 90 epidemiologic studies of both occupational and environmental exposure have been published, and numerous reviews (e.g., references 2-6) of this literature exist. Most of the existing reviews have not evaluated the published studies in depth (e.g., references 3 and 7-10). Some (e.g., references 4, 5, and 11) have included several noncancer outcomes, thus broadening their research base and inhibiting extensive review of individual papers. Most have uncritically accepted whatever means of exposure assessment may have been used, when exposure assessment is the most critical and least understood element of these studies of electric and magnetic fields. This review focuses specifically on published occupational and environmental epidemiologic studies of exposure to power-frequency (50to 60-Hz) electric and magnetic fields and brain cancer and leukemia. Although several study design issues are discussed, we emphasize techniques for assessing exposure to electric and magnetic fields. The large variation in study design and quality among the papers reviewed precludes any meaningful quantitative analysis (such as meta-analysis), but it is possible among studies of a given design to select those with exposure assessment methodology most likely to rank subjects by actual exposure to electric and magnetic fields and to concentrate on those results. This we have attempted to