HealthDay News — Air pollution and ozone exposure may in part explain geographical variation in mammographic density, according to a study published online April 6 in Breast Cancer Research.
Lusine Yaghjyan, MD, PhD, MPH, an assistant professor of epidemiology at the University of Florida in Gainesville, and colleagues evaluated the records of 279,967 women, aged 40 and older, who had mammograms. The team assessed ambient air pollutants and ozone exposure and the association with breast density.
The researchers found that women with heterogeneously dense versus scattered fibroglandular breasts were more likely to have higher exposure to fine particle matter (fourth versus first quartile odds ratio, 1.19). The team found that high ozone levels had the opposite effect on breast density.
As to why the pollution may be linked to more dense breast tissue, “it appears some of the chemicals that might be in those fine particles might have properties disrupting normal endocrine function,” Yaghjyan told HealthDay. “It’s the first step and we need more studies, especially trying to understand if there is a causal link or just an association. This [study] does not show any causal link. For us to prove causality, we need much more than a single study.”