[Is there an increased risk of leukemia, brain tumors or breast cancer after exposure to high-frequency radiation? Review of methods and results of epidemiologic studies].

BACKGROUND: There are only a few epidemiologic studies investigating risk factors in persons occupationally exposed to high-frequency radiation (e.g. radio-, TV-waves, mobile phones or microwaves). The results of the studies are mostly inconsistent.
METHODS: All epidemiologic studies which investigated the association between occupational exposure to high-frequency radiation and the risk of leukemia, brain tumors or breast cancer were included in this review. All studies published between 1980 and 1997, such as record-linkage, case-control, and cohort studies, were retrieved from MEDLINE. Incidence and mortality studies are included. Methodologic problems of these investigations are discussed.
RESULTS: Most of the recent epidemiologic studies do not present quantitative exposure data or data on the specific frequencies of electro magnetic fields. In general, the relative risks for leukemia, brain tumors or breast cancer are small, not significant and inconsistent. Confounder variables were not included in most of the analyses and no dose-response relationship was reported.
CONCLUSION: To increase the power and the validity of the studies a re-analysis based on original data of all previous studies in this field is recommended. Additionally, to investigate the influence of high-frequency radiation on the development of cancer, international epidemiologic studies are necessary. Only they would have sufficient sample size to detect small elevated risks.