LUNG-CANCER IN RELATION TO EMPLOYMENT IN THE ELECTRICAL UTILITY INDUSTRY AND EXPOSURE TO MAGNETIC-FIELDS

Objectives-A recent study found that lung cancer may be associated wit h exposures encountered in the electrical utility industry. To further evaluate this possibility, data were collected and analysed from five large electrical utility companies in the United States. Methods-A co hort of 138 905 male workers employed between 1950 and 1986 was follow ed up for mortality to the end of 1988, with 20 733 deaths identified of which 1692 were due to lung cancer. Mortality from lung cancer was examined in relation to the duration of employment in specific jobs th ought to have high exposure to 60 Hz magnetic fields and to an index o f cumulative exposure to magnetic fields based on personal measurement s. Exposure to pulsed electromagnetic fields (PEMFs) as estimated from another study was also considered. Poisson regression generated rate ratios for categories of exposure based on comparisons within the coho rt adjusted for age, calendar year, race, socioeconomic status, work s tatus, and estimated exposure to asbestos. Results-Mortality rose mode stly with duration of work as an electrician or power plant operator r eaching rate ratios of 1.4 with greater than or equal to 20 years in t hose jobs but not with duration of work as a lineman or a combination of jobs thought to have high exposures to 60 Hz magnetic fields or PEM Fs. Cumulative indices of exposure to 60 Hz magnetic fields and PEMFs were both associated with rate ratios of 1.2-1.3 in the highest interv als. Conclusions-These data suggest that lung cancer is not strongly a ssociated with duration of employment in specific jobs associated with high potential exposure to 60 Hz magnetic fields or to PEMFs. Small a ssociations of lung cancer with indices of both 60 Hz magnetic fields and PEMFs leave open the possibility that larger associations have bee n diluted through exposure misclassification. Refined exposure assessm ent, especially to PEMFs, would be required to evaluate that possibili ty.