Breast cancer among Danish women occupationally exposed to diesel exhaust and polycyclic aromatic hydrocarbons, 1964–2016

Abstract

OBJECTIVE: The aim of this study was to explore the association between occupational exposure to diesel exhaust and polycyclic aromatic hydrocarbons (PAH), respectively, and breast cancer subtypes. METHODS: The study included 38 375 women <70 years with incident breast cancer, identified in the Danish Cancer Registry, and 5 breast cancer-free controls per case who were randomly selected from the Danish Civil Registration System and matched on year of birth. Full employment history was obtained for all study subjects from a nationwide pension fund, and exposure to diesel exhaust and PAH was assessed using a job exposure matrix. Conditional logistic regression was used for estimation of odds ratios (OR) with adjustment for reproductive factors and socioeconomic status. RESULTS: No noteworthy associations were observed for overall breast cancer in women exposed to diesel exhaust. However, diesel exhaust modestly elevated the risk of estrogen receptor negative breast tumors before age 50 [OR 1.26, 95% confidence interval (CI) 1.09–1.46]. Duration– and dose–response relationships were further observed for this subtype in this age group. No notable risk patterns were generally observed for PAH exposure. CONCLUSION: Occupational exposure to diesel exhaust may increase the risk of early-onset estrogen receptor negative breast tumors in women. Future studies exploring this association are warranted.

Keywords

• occupational risk factor
• diesel exhaust
• female worker
• job exposure matrix
• pah
• jem
• exposed
• full job history
• breast cancer subtype
• occupational exposure
• exposure
• women
• cancer
• breast cancer
• polycyclic aromatic hydrocarbon
• denmark