Long-term atmospheric exposure to particulate matter and breast cancer risk: findings from a nested case-control study in France

Abstract Background Airborne particulate matter (PM) is a complex mixture of particles thought to be associated with a range of adverse health effects, including female breast cancer. Current evidence on the association between PM and female breast cancer risk is inconsistent. Methods This study investigated the association between long-term exposure to PM and breast cancer risk in a nested case-control study within the French E3N-Generation cohort including 5222 breast cancer cases identified over the 1990–2011 follow-up period and 5222 individually matched controls. Annual mean concentrations of PM 10 and PM 2.5 at participants’ residential addresses, were estimated using a land use regression model. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using conditional logistic regression models. Results ORs for each 10 µg/m 3 increase in the average of PM 2.5 and PM 10 were 1.14 (95% CI: 0.99–1.30) and 1.08 (95% CI: 0.98–1.18), respectively. When restricted to invasive ductal and lobular carcinomas, ORs were 2.74 (95% CI: 1.05–7.15) for PM 2.5 and 2.05 (95% CI: 1.11–3.78) for PM 10 . Comparable effects of PM exposure estimated by a chemistry transport model reinforces these findings. Conclusion This study suggests a potential association between PM 2.5 and PM 10 exposure and breast cancer risk.