Occupational exposure to electromagnetic field and breast cancer risk in a large, population-based, case-control study in the United States.

Objective: Our objective was to evaluate women who were occupationally exposed to electromagnetic fields (EMF) and breast cancer risk.
Methods: Women diagnosed with breast cancer (n=6213) and randomly selected age-matched control subjects (n=7390) provided breast cancer risk factor information and occupational history. A qualified industrial hygienist classified each job for EMF exposure as background, low, medium, or high.
Results: When compared with the referent of background exposure, the odds ratio adjusted for age and state of residence was 1.06 (95% CI=0.99-1.14) for low exposure, 1.09 (95% CI=0.96-1.23) for medium exposure, and 1.16 (95% CI=0.90-1.50) for high exposure.
Conclusion: Our findings, taken together with previous epidemiological studies, suggest that exposure to EMF in the workplace may be associated with a slight elevation in breast cancer risk.