Occupational Exposure to Extremely Low-Frequency Magnetic Fields and Postmenopausal Breast Cancer Risk.

Abstract

To estimate the association between occupational exposures to extremely low-frequency magnetic fields (ELF-MF) and postmenopausal breast cancer. Lifetime job histories from a population-based case-control study (2008 to 2011) of histologically confirmed breast cancer in Montréal, Canada, were linked to a job-exposure matrix to assign geometric mean ELF-MF exposure/workday. Logistic regression estimated odds ratios and 95% confidence intervals for cumulative, average, maximum, and duration of maximum exposure to ELF-MFs (per interquartile range increase), adjusting for individual-level and ecological covariables. Data from 663 cases and 592 controls revealed no association between occupational ELF-MF exposure and postmenopausal breast cancer, though restricting exposures to 0 to 10 years before interview and to those during breast development, some positive associations was observed, particularly for ER+/PR+ tumors. Our findings suggest no association between occupational ELF-MF exposure and postmenopausal breast cancer risk.