A meta-analysis of epidemiologic studies of electric and magnetic fields and breast cancer in women and men.

This paper reviews 43 publications that provide information about possible associations between exposure to electric and magnetic fields (EMF) at work or at home and risks of breast cancer in women and men. Estimation of relative risk associated with exposure was possible for 24 studies among women and 15 among men. The data are grouped in relation to gender of study subjects, type of study, geographical location, and method used to assess exposure, with corresponding precision-weighted estimates of pooled relative risks (RRs). The chi(2) statistics are used to assess the degree to which differences between studies, within subgroups, may be attributable simply to sampling variability. The pooled RR from studies in women was 1.12 (95% CI: 1.09, 1.15), but variations between the contributing results are not easily attributable to chance (P = 0.0365). A fairly homogeneous increased risk was found for men (a pooled RR of 1.37, with 95% confidence limits of 1.11, 1.71, and homogeneity P-value = 0.1101). However, in both genders, results from individual studies are very variable and in part contradictory. The paramount methodological problem inhibiting valid conclusions about an association between EMF and breast cancer is the probable misclassification of exposure and the possible misclassification of the disease itself. Copyright 2001 Wiley-Liss, Inc.