Living in areas with high levels of air pollution can affect a woman's breast density

Based on a new study published in
, a study of nearly 280,000 women has found that living in areas with high levels of fine particulate matter caused by air pollution may increase a woman's chances of having dense breasts, which have been identified as a risk factor for breast cancer.
the study, the largest of its kind to look at the link between air pollution and breast density, found that for every unit increased in fine particulate matter concentration (PM2.5), women were 4 percent more likely to have dense breasts. Women with dense breasts were about 20 percent more likely to have been exposed to high concentrations of PM2.5. In contrast, women with lower breast density, or more adipose tissue in their breasts, were 12 percent less likely to have been exposed to high concentrations of PM2.5.
breast density is measured by breast photography and reflects the relative content of different tissue types in the breast. Most breasts of adipose tissue are easier to interpret through breast photography and therefore easier to observe abnormalities. Dense breasts contain a higher proportion of fibrous gland tissue, which makes breast photography blurry and difficult to identify abnormalities such as breast tumors.
Lead author Dr Lusine Yaghjyan, from the University of Florida, said: "Our findings suggest that previously reported geoscic changes in breast density can be partly explained by different air pollution patterns in urban and rural areas. Breast density has been identified as a strong risk factor for breast cancer, so future studies will determine whether the observed association has a causal relationship, which, once identified, can have implications for risk prevention. The
also considered the link between ozone exposure and breast density among the 280,000 women involved in the study. They found that for every unit increased in ozone concentration, there was a 3% reduction in the chance of having dense breasts.
Yaghjyan explained: "We found a positive correlation between fine particulate matter concentration exposure and breast density, while ozone exposure was negatively related to breast density. This interesting results need further research to uncover any biological mechanisms that may lead to ozone exposure reducing a woman's chances of having dense breasts. "It has been known that the chemical composition of PM2.5 air pollution contains pollutants that disrupt endocrine properties. According to the researchers, although causation could not be established in this observational study due to uncontrolled factors, these contaminants may potentially affect breast density by interfering with cell growth in the breast and increasing the relative content of fibroblast tissue.
who conducted the study were selected from the Breast Cancer Surveillance Consortium, a population-based queue study of women screened for breast photography in the United States. Breast photography data, including breast density, came from women screened between 2001 and 2009. Breast density is measured using the BI-RADS system, developed by the American College of Radiology to standardize breast density measurements. The women's corresponding air pollution data before or in the area where they lived at the time were obtained from the U.S. Environmental Protection Agency. (Source: BioMedCentral Open Access Publishing)