Women living in areas of the United States with poor air quality, particularly neighborhoods with high motor vehicle emissions, face a greater risk of developing breast cancer, according to a comprehensive multiyear study published in the American Journal of Public Health and reported on MedicalXpress.
The research, led by Alexandra White of the National Institutes of Health and involving over 400,000 women and 28,000 breast cancer cases, found a clear association between air pollution and breast cancer incidence. The study pooled data from five large-scale breast cancer studies spanning several decades, tracking participants across different locations and up to 10 years prior to diagnosis. Air quality data from more than 2,600 monitoring sites were integrated to assess exposure levels.
Key findings include:
- A 10 parts-per-billion increase in nitrogen dioxide (NO₂), which is a marker of traffic-related pollution, was linked to a 3% rise in overall breast cancer cases. With an estimated 316,950 cases expected in the U.S. this year, that increase could translate to 9,500 additional diagnoses.
- A 5 microgram-per-cubic-meter increase in PM2.5 (fine particulate matter) was associated with a higher incidence of hormone receptor-negative breast cancer, a more aggressive and harder-to-treat form of the disease.
Veronica Irvin of Oregon State University, one of the study’s co-authors, emphasized the need for stronger environmental policies: “It’s often not realistic for people to relocate to areas with cleaner air, so we need more effective clean air laws to protect those most at risk,” she said. Irvin also noted that the average NO₂ levels observed were below current EPA guidelines, suggesting that even legally acceptable pollution levels may pose health risks.
The study underscores the importance of reducing traffic emissions and promoting alternative transportation methods. Despite relatively lower pollution levels compared to other populous nations, breast cancer rates in the U.S. have been steadily rising over the past 40 years. It remains the second leading cause of cancer death among women, following lung cancer.
The research team included scientists from Harvard University, the University of Washington, Indiana University, Stony Brook University, UC San Diego, The Ohio State University, and UNC Chapel Hill.
