A synthesis of epidemiologic research on cancer risks from power-frequency magnetic fields at work.
Bowman-JD; Smith-RJ; Stayner-L
American Industrial Hygiene Conference and Exposition, May 9-15, 1998, Atlanta, Georgia. Fairfax, VA: American Industrial Hygiene Association, 1998 May; :39-40
Nearly 100 epidemiologic studies have examined cancer risks from occupational exposures to power-frequency electric and magnetic fields (EMF). Some have reported significant associations with brain cancer and leukemia, but these findings have been inconsistent. One explanation for these results is that EMF interact with biological structures through unproven physical mechanisms to increase the risks of some adult cancers during later stages of carcinogenesis. An alternative hypothesis is that most workplace EMF are too weak to affect biological tissues so the epidemiologic associations are artifacts. To assess the strength of the epidemiologic evidence on occupational EMF and cancer, we conducted a meta-analysis of the studies with personal measurements for the TWA magnitude of power-frequency magnetic fields. These eight studies all used sound epidemiologic methods, but differed in the size of the study population, work environments (electric utilities vs. other industries), outcomes (cancer incidence vs. mortality), and specificity of links between exposures measurements and subject work histories. When we considered the highest quality studies that assessed exposures SB10 years before cancer diagnosis or death, the dose-response relationship was significant for brain cancer (1.86-fold increase in the odds ratio for 1 mT increase in exposure, p<0.001) and nearly significant for chronic lymphocytic leukemia (4.07-fold increase per mT, p=0.082). Including the weaker study, the brain cancer dose-response was not significant (p=0.16). No significant dose-response with power-frequency magnetic fields was found for any other cancer studied in men. This synthesis of epidemiologic findings provides some support for the hypothesis that increasing workers' TWA magnetic field exposure may raise their risk of brain cancer and, with less certainty, chronic lymphocytic leukemia.
Electrical-fields; Electromagnetic-fields; Electromagnetic-radiation; Magnetic-fields; Epidemiology; Cancer; Brain-tumors; Leukemogenesis; Lymphocytes; Blood-disorders; Risk-analysis; Carcinogenesis; Biological-systems; Time-weighted-average-exposure; Exposure-assessment; Employee-exposure
American Industrial Hygiene Conference and Exposition, May 9-15, 1998, Atlanta, Georgia