Breast cancer and electromagnetic fields - A review

PURPOSE: Several statements have been issued to the effect that no consiste nt, significant Link has been demonstrated between cancer and electromagnet ic fields (EMF). However, there continues to be much interest in a possible association with breast cancer, in part because breast cancer risk is subs tantially higher in industrialized countries than in other areas, and elect ric power generation and consumption is one of the hallmarks of industriali zed societies. In 1987, Stevens proposed a biological mechanism whereby two products of electric power generation, EMF and light at night, might contr ibute to mammary carcinogenesis through inhibition of melatonin. METHODS: We conducted a comprehensive review of the epidemiologic literatur e and hypothesized mechanisms pertaining to EMF exposure and the risk of br east cancer, in order to assess whether or not there was evidence to sugges t a link between EMF and breast cancer. RESULTS: Some occupational epidemiological studies have demonstrated an inc reased incidence of breast cancer among mainly male electrical workers. It has been difficult to study women, as few are employed in these types of oc cupations. In all, there have been eleven occupational studies related to b reast cancer in women, and statistically significant risk ratios have been observed: 1.98 for premenopausal women in occupations with high EMF exposur e in one study, 2.17 in all women who worked as telephone installers, repai rers, and line workers in another study, and 1.65 for system analysts/progr ammers, 1.40 for telegraph and radio operators, and 1.27 for telephone oper ators in a third study. However, six of the studies did not find any signif icant effects and two found effects only in subgroups. The results of the e ight studies of residential exposure and four electric blanket studies have been inconsistent, with most not demonstrating any significant association . However, this might be attributed, at least to some extent, to difficulti es in assessing residential exposure in these studies, as well as other met hodological considerations. CONCLUSIONS: The biologic plausibility of an association between EMF and br east cancer, coupled with suggestive data from occupational studies and une xplained high incidence rates of breast cancer, suggests that further inves tigation of this possible association is warranted. Ann Epidemiol 2000;10:3 1-44. Published by Elsevier Science Inc.