title: Leukemia, brain tumors, and exposure to extremely low frequency electromagnetic fields in Swiss railway employees.
abstract: Railway engineers provide excellent opportunities for studying the relation between exposure to extremely low frequency magnetic fields and leukemia or brain tumors. In a cohort study of Swiss railway personnel with 2.7 x 10(5) person-years of follow-up (1972--1993), the authors compared occupations with high average exposures (line engineers: 25.9 microT) to those with medium and low exposures (station masters: 1 microT). The mortality rate ratio for leukemia was 2.4 (95% confidence interval (CI): 1.0, 6.1) among line engineers (reference category: station masters). The mortality rate ratio for brain tumors was 1.0 (95% CI: 0.2, 4.6) among line engineers and 5.1 (95% CI: 1.2, 21.2) among shunting yard engineers (compared with station masters). Two exposure characteristics were evaluated: cumulative exposure in microT-years and years spent under exposure to magnetic fields of > or =10 microT. There was a significant increase in leukemia mortality of 0.9% (95% CI: 0.2, 1.7) per microT-year of cumulative exposure to extremely low frequency magnetic fields. The increase by years spent under exposure of > or =10 microT was even stronger: 62% per year (95% CI: 15, 129). Brain cancer risk did not show a dose-response relation. This study contributes to the evidence for a link between heavy exposure to extremely low frequency magnetic fields and leukemia. Its strengths include reliable measurements and reliable historical reconstruction of exposures.
authors.affiliation: Institute for Social and Preventive Medicine, University of Berne, Berne, Switzerland. minder@ispm.unibe.ch
authors.forename: C E
authors.initials: CE
authors.lastname: Minder
authors.forename: D H
authors.initials: DH
authors.lastname: Pfluger
mesh_terms: D000328:Adult; D001932:Brain Neoplasms / Q000453:epidemiology* / Q000401:mortality; D015984:Causality; D015331:Cohort Studies; D015986:Confounding Factors, Epidemiologic; D004307:Dose-Response Relationship, Radiation; D004574:Electromagnetic Fields / Q000009:adverse effects*; D023381:Endpoint Determination; D005500:Follow-Up Studies; D006801:Humans; D007938:Leukemia / Q000453:epidemiology* / Q000401:mortality; D008297:Male; D009381:Neoplasms, Radiation-Induced / Q000453:epidemiology* / Q000401:mortality; D016273:Occupational Exposure / Q000009:adverse effects* / Q000706:statistics & numerical data; D016017:Odds Ratio; D011890:Railroads / Q000706:statistics & numerical data*; D015203:Reproducibility of Results; D018570:Risk Assessment; D012307:Risk Factors; D013557:Switzerland / Q000453:epidemiology; D013997:Time Factors