Air Pollutants and Breast Cancer Risk: A Parallel Analysis of Five Large US Prospective Cohorts
Alexandra J White1, Jaime E Hart1, Sabah M Quraishi1
1Alexandra J. White and Dale P. Sandler are with the Epidemiology Branch, National Institute of Environmental Health Sciences, Research Triangle Park, NC. Jaime E. Hart and Francine Laden are with the Department of Environmental Health, Harvard T. H. Chan School of Public Health, Boston, MA. At the time of this work, Sabah M. Quraishi was with the Department of Environmental and Occupational Health Sciences, University of Washington School of Public Health, Seattle, WA. Deborah B. Bookwalter is with Public Health and Epidemiology Practice, Westat, Rockville, MD. Marina R. Sweeney is with Social & Scientific Systems, a DLH Holdings Company, Durham, NC. Elizabeth W. Spalt and Joel D. Kaufman are with the Department of Environmental and Occupational Health Sciences, University of Washington School of Public Health, Seattle. Michael S. Hendryx is with the Department of Environmental and Occupational Health, Indiana University School of Public Health, Bloomington. Veronica L. Irvin is with the College of Health, Oregon State University, Corvallis. Dorothy S. Lane is with the Department of Family, Population, and Preventive Medicine, Stony Brook University, Stony Brook, NY. Aladdin H. Shadyab is with the Herbert Wertheim School of Public Health and Human Longevity Science, University of California San Diego, La Jolla. Shawnita Sealy-Jefferson is with the Division of Epidemiology, College of Public Health, The Ohio State University, Columbus. Marian L. Neuhouser is with the Division of Public Health Sciences, Fred Hutchinson Cancer Center and School of Public Health, University of Washington, Seattle. Eric A. Whitsel is with the Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill.
Abstract:
Objectives. To determine whether outdoor air pollution exposure is associated with breast cancer incidence. Methods. Residential-level concentrations of nitrogen dioxide (NO2, parts per billion [ppb]), fine particulate matter (PM2.5; ≤ 2.5 μ/m3) and ozone (ppb) in the United States were estimated for participants of the Nurses' Health Studies, Women's Health Initiative Clinical Trials and Observational Study Cohort, and Sister Study using high-resolution spatiotemporal models. Cox proportional hazards regression estimated cohort-specific hazard ratios (HRs) and 95% confidence intervals (CIs), and a random effects model determined summary HRs, overall and by estrogen receptor (ER)/progesterone receptor (PR) subtype and census region. Results. NO2 was positively associated with overall breast cancer incidence (n = 28 811 cases; HR = 1.03; 95% CI = 1.00, 1.05), with little variation by subgroups. PM2.5 was associated with higher incidence of ER-/PR- tumors (n = 2367 cases; HR = 1.14; 95% CI = 1.04, 1.24; P-heterogeneity < .001) and with higher overall incidence in the Midwest (HR = 1.15; 95% CI = 1.01, 1.32; P-heterogeneity = .01). Ozone was not associated with overall incidence, but was associated with ER-/PR- tumors (n = 3406 cases; HR = 1.10; 95% CI = 1.00, 1.21; P-heterogeneity = .03). Conclusions. In this largest US study to date, we confirmed an association between NO2 and breast cancer, and we present novel associations of PM2.5 and ozone with ER-/PR- tumors. (Am J Public Health. 2025;115(12): 2030-2043. https://doi.org/10.2105/AJPH.2025.308247).
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