title: Occupational exposure to magnetic fields and breast cancer among Canadian men.
abstract: Occupational magnetic field (MF) exposure has been suggested as a risk factor for breast cancer in both men and women. Due to the rarity of this disease in men, most epidemiologic studies investigating this relationship have been limited by small sample sizes. Herein, associations of several measures of occupational MF exposure with breast cancer in men were investigated using data from the population-based case-control component of the Canadian National Enhanced Cancer Surveillance System. Lifetime job histories were provided by 115 cases and 570 controls. Average MF exposure of individual jobs was classified into three categories (<0.3, 0.3 to <0.6, or ≥0.6 μT) through expert blinded review of participant's lifetime occupational histories. The impact of highest average and cumulative MF exposure, as well as exposure duration and specific exposure-time windows, on cancer risk was examined using logistic regression. The proportion of cases (25%) with a highest average exposure of ≥0.3 μT was higher than among controls (22%). We found an elevated risk of breast cancer in men who were exposed to ≥0.6 μT (odds ratio [OR] = 1.80, 95% CI = 0.82-3.95) when compared to those with exposures <0.3 μT. Those exposed to occupational MF fields for at least 30 years had a nearly threefold increase in risk of breast cancer (OR = 2.77, 95% CI = 0.98-7.82) when compared to those with background levels of exposure. Findings for the other time-related MF variables were inconsistent. Our analysis, in one of the largest case-control studies of breast cancer in men conducted to date, provides limited support for the hypothesis that exposure to MF increases the risk breast cancer in men.
authors.affiliation: Department of Cancer Epidemiology and Prevention Research, Alberta Health Services - Cancer Control Alberta, Calgary, Alberta, Canada.
authors.forename: Anne
authors.initials: A
authors.lastname: Grundy
authors.affiliation: Prevention and Cancer Control, Cancer Care Ontario, Toronto, Ontario, Canada.|Occupational Cancer Research Center, Cancer Care Ontario, Toronto, Ontario, Canada.|Division of Occupational and Environmental Health, Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada.|Division of Epidemiology, Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Shelley A
authors.identifier: http://orcid.org/0000-0003-2306-7921
authors.initials: SA
authors.lastname: Harris
authors.affiliation: Occupational Cancer Research Center, Cancer Care Ontario, Toronto, Ontario, Canada.|Division of Occupational and Environmental Health, Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Paul A
authors.initials: PA
authors.lastname: Demers
authors.affiliation: Department of Epidemiology and Community Medicine, University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: Kenneth C
authors.initials: KC
authors.lastname: Johnson
authors.affiliation: University of Ontario Institute of Technology, Oshawa, Ontario, Canada.
authors.forename: David A
authors.initials: DA
authors.lastname: Agnew
authors.affiliation: Department of Health Sciences, Carleton University, Ottawa, Ontario, Canada.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Villeneuve
mesh_terms: D000328:Adult; D000368:Aged; D018567:Breast Neoplasms, Male / Q000453:epidemiology* / Q000209:etiology*; D002170:Canada / Q000453:epidemiology; D016022:Case-Control Studies; D006801:Humans; D016015:Logistic Models; D060526:Magnetic Fields / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure / Q000009:adverse effects*; D016017:Odds Ratio
keywords: Case-control study; magnetic fields; male breast cancer; occupational exposure