Epidemiological evidence on the association between ambient air pollution and breast cancer risk is inconsistent.
We examined the association between long-term exposure to ambient air pollution and incidence of postmenopausal breast cancer in European women.
In 15 cohorts from nine European countries, individual estimates of air pollution levels at the residence were estimated by standardized land-use regression models developed within the European Study of Cohorts for Air Pollution Effects (ESCAPE) and Transport related Air Pollution and Health impacts – Integrated Methodologies for Assessing Particulate Matter (TRANSPHORM) projects: particulate matter (PM) ≤2.5μm, ≤10μm, and 2.5–10μm in diameter (PM
, PM
, and PM
, respectively); PM
absorbance; nitrogen oxides (NO
and NO
); traffic intensity; and elemental composition of PM. We estimated cohort-specific associations between breast cancer and air pollutants using Cox regression models, adjusting for major lifestyle risk factors, and pooled cohort-specific estimates using random-effects meta-analyses.
Of 74,750 postmenopausal women included in the study, 3,612 developed breast cancer during 991,353 person-years of follow-up. We found positive and statistically insignificant associations between breast cancer and PM
{hazard ratio (HR)=1.08 [95% confidence interval (CI): 0.77, 1.51] per 5 μg/m
}, PM
[1.07 (95% CI: 0.89, 1.30) per 10 μg/m
], PM
[1.20 (95% CI: 0.96, 1.49 per 5 μg/m
], and NO
[1.02 (95% CI: 0.98, 1.07 per 10 μg/m
], and a statistically significant association with NO
[1.04 (95% CI: 1.00, 1.08) per 20 μg/m
,
=0.04].
We found suggestive evidence of an association between ambient air pollution and incidence of postmenopausal breast cancer in European women. https://doi.org/10.1289/EHP1742....

Long-Term Exposure to Ambient Air Pollution and Incidence of Postmenopausal Breast Cancer in 15 European Cohorts within the ESCAPE Project

10.1289/EHP1742