Women's occupational exposure to polycyclic aromatic hydrocarbons and risk of breast cancer.

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.