SHORT REPORT Risk for leukaemia and brain and breast cancer among Danish utility workers: a second follow-up

Objective: To update a study of risks for leukaemia, brain cancer and breast cancer in a Danish nationwide, population-based cohort of utility employees. Methods: A multivariate statistical model including information on age, duration of employment, date of first employment and level of occupational exposure to electromagnetic fields was applied. Results: No increased risk for these cancers was seen among 28 224 subjects with more than 3 months of employment in whom cancer had not been diagnosed before first employment. Conclusion: The results do not support the hypothesis of an association between occupational exposure to magnetic fields in the electric utility industry and risks for leukaemia, brain cancer and breast cancer. O ccupational exposure to extremely low-frequency (50– 60 Hz) electromagnetic fields (ELF-EMF) has been investigated as a possible cause of leukaemia and brain and breast cancer in many epidemiological studies. The Danish utility worker cohort consisted of all employees at the 99 utility companies that have supplied all of Denmark with electricity since the beginning of the past century. This nationwide cohort has been followed-up for pacemaker implantation,1 diseases of the central nervous system,2 3 cause-specific mortality4 and cancer incidence.5 In the study reported in this paper, we used a revised job-exposure matrix to investigate the risks for leukaemia and brain and breast cancer, which are the cancers suspected a priori to be associated with exposure to EMF. MATERIAL AND METHOD