Long-term exposure to air pollution at residential and workplace addresses and breast cancer risk: A case-control study nested in the French E3N-Générations cohort from 1990 to 2011.

BACKGROUND

An increasing evidence links air pollution to breast cancer (BC) risk. Yet, pollutant exposure estimates at the workplace location in pollution exposure assessment have not been considered.

OBJECTIVES

This study investigates the association between particulate matters (PM, PM) and nitrogen dioxide (NO) atmospheric concentrations (1990-2011), at the women's residential and workplace locations, and BC risk.

METHODS

This case-control study of 2419 BC cases and 2984 controls, was nested in the French prospective E3N cohort. The annual mean PM, PM and NO concentrations were estimated using a Land Use Regression model (50 m x 50 m resolution) and assigned to the women's geocoded residential and workplace locations, from cohort recruitment to their index date (date of case diagnosis). Odds ratios (OR) and 95 % confidence intervals (CI) were estimated using multivariate logistic regression models.

RESULTS

An increased BC risk was observed for a 10 µg/m increase of the 1990-2011 average PM concentration estimates (OR=1·28; CI 1·00, 1·63). An increased risk was suggested for a 10 µg/m increase for PM (OR=1·09; CI 0·92, 1·30) and NO (OR=1·05; CI 0·97, 1·13). No effect modification by menopausal status, nor difference by hormone receptor status were observed.

DISCUSSION

This study is the first to estimate BC risk and long-term air pollutant exposure from both, residential and workplace location histories. Results suggest that residential PM, PM and NO concentrations are strongly correlated with workplace ones, indicating that residential data may serve as proxy for overall exposure. Future studies should consider exposure during commuting.