Objective To estimate the association between occupational polycyclic aromatic hydrocarbon (PAH) exposure and female breast cancer.
Methods Lifetime work histories for 1130 cases and 1169 controls from British Columbia and Ontario (Canada) were assessed for PAH exposure using a job-exposure matrix based on compliance measurements obtained during US Occupational Safety and Health Administration workplace safety inspections.
Results Exposure to any level of PAHs was associated with an increased risk of breast cancer (OR=1.32, 95% CI: 1.10 to 1.59), as was duration at high PAH exposure (for >7.4 years: OR=1.45, 95% CI: 1.10 to 1.91; ptrend=0.01), compared with women who were never exposed. Increased risk of breast cancer was most strongly associated with prolonged duration at high occupational PAH exposure among women with a family history of breast cancer (for >7.4 years: OR=2.79, 95% CI: 1.25 to 6.24; ptrend<0.01).
Conclusions Our study suggests that prolonged occupational exposure to PAH may increase breast cancer risk, especially among women with a family history of breast cancer.
- exposure assessment
- polyaromatic hydrocarbons (pahs)
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Contributors DGL designed the exposure assessment tool, cleaned and performed the statistical analysis of the data and drafted and revised the paper. IB helped design the exposure assessment tool with DGL, co-wrote the statistical analysis plan, assisted the statistical analysis and helped draft and revise the paper. ASL was responsible for the majority of the data collection, monitored data collection for the whole study and revised the paper. AG helped clean and analyse the data, and revised the paper. MCF assisted the statistical analysis and revised the paper. KJA is one the co-PI of the study, co-designed the study with JJS, co-wrote the statistical analysis plan with JJS and IB, ran the Ontario study centre and helped draft and revise the paper. JJS is one the co-PI of the study, co-designed the study with KJA, co-wrote the statistical analysis plan with KJA and IB, ran the BC study centre, assisted the statistical analysis and helped draft and revise the paper.
Funding Funding for this study was provided by a grant from the Canadian Institutes of Health Research (Funding Reference #: 69036). MCF was supported by the Intramural Research Program of the Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health.
Competing interests None declared.
Patient consent Not required.
Ethics approval University of British Columbia/BC Cancer Agency Research Ethics Board, Queen’s University Health Sciences Research Ethics Board.
Provenance and peer review Not commissioned; externally peer reviewed.
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