Authored By:
Sorahan TThese two papers describe a cohort study which investigated whether occupational exposure to extremely low frequency magnetic fields is associated with leukaemia and brain tumours (glioma and meningioma). The cohort which included 73,051 electricity supply workers in England and Wales was investigated for the incidence of leukaemia and brain tumours during the period 1973-2010. Exposure to occupational magnetic fields was calculated using engineering data to determine the average magnetic fields in specified areas of work and then applied to information about the time spent in these areas. There were no overall statistically significant associations between exposure to magnetic fields and leukaemia and glioma. For meningioma, there was some evidence of elevated risks for higher exposures received for more than 10 years. The author concludes that the study found no convincing evidence to support the hypothesis that exposure to magnetic fields is a risk factor for leukaemia and glioma. The author argues that the limited positive findings for meningioma may be chance findings.
Magnetic fields and brain tumour risks in UK electricity supply workers
Published In:
Occup Med (Lond) 2014: both papers are in pressThere have been a number of epidemiological studies investigating whether occupational exposure to ELF magnetic fields is associated with cancer. Studies conducted in the 1980s and early 1990s pointed to a possible increased risk of leukaemia, brain tumour and breast cancer in occupations with presumed elevated exposure (e.g. workers in electricity supply). The interpretation of these studies was difficult mainly due to methodological limitations and lack of appropriate exposure measurements.
More recent studies have made use of improved methods for individual assessment of occupational exposure to ELF magnetic fields and potential occupational confounders. Modern exposure assessment methods include the combined use of systematic workplace measurements and calculations and individual job history descriptions as was done in the current study. However, because the magnetic field exposure within occupational groups is highly variable, these exposure assessment methods do not eliminate all uncertainties regarding the workers' exposure levels.
Overall there is no consistent evidence showing that occupational magnetic fields are associated with cancer.
