Occupational exposures to extremely low frequency magnetic fields and postmenopausal breast cancer.
BACKGROUND
The association between occupational exposure to extremely low frequency magnetic fields (ELF-MF) and risk of postmenopausal breast cancer was assessed in a case-control study.


METHODS
Breast cancer cases were compared to cancer controls. Interviewers elicited information on risk factors and on lifetime work history. Industrial hygienists assigned to each job average duration of exposure to ELF-MF at four levels of intensities ("none," <0.2 microT; "low," 0.2-<0.5microT; "medium," 0.5-<1microT; "high," > or =1-10microT). Unconditional logistic regression was used to estimate adjusted odds ratios (OR) and 95% confidence intervals (95% CI).


RESULTS
A total number of 608 cases and 667 controls participated. Adjusting for accepted breast cancer risk factors, we found an OR of 1.13 for lifetime occupational exposure to ELF-MF at medium or high intensities. Risks were larger for exposures before age 35 (OR = 1.40), and statistically significant for exposures before 35 among cases with progesterone receptor positive tumors (OR = 1.56, 95% CI=1.02-2.39).


CONCLUSIONS
There appears to be a small increased risk for breast cancer among postmenopausal women exposed occupationally to ELF-MF.
Labrèche
France
F
Montreal Department of Public Health, Montreal, Quebec, Canada. flabrech@santepub-mtl.qc.ca
Goldberg
Mark S
MS
Valois
Marie-France
MF
Nadon
Louise
L
Richardson
Lesley
L
Lakhani
Ramzan
R
Latreille
Benoit
B
D000368:Aged; D001943:Breast Neoplasms / Q000453:epidemiology* / Q000209:etiology; D002170:Canada / Q000453:epidemiology; D004574:Electromagnetic Fields / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008875:Middle Aged; D009784:Occupational Diseases / Q000453:epidemiology* / Q000209:etiology; D016273:Occupational Exposure / Q000009:adverse effects*; D017698:Postmenopause; D012307:Risk Factors