Air Pollution May Be Linked to Breast Cancer Risk Factor
One risk factor for breast cancer is breast density. Learn here how air pollution contributes to dense breasts.
Breast density is a way to describe the composition of the tissue in a woman’s breast. Breasts are made up mostly of fat and breast tissue (a network of milk producing sacs and milk carrying ducts) all bound together with connective tissue. High breast density indicates a greater amount of breast and connective tissue compared to fat while low breast density indicates a greater proportion of fat.
Past studies have suggested that women with very dense breasts may be four to five times more likely to develop breast cancer than women with low breast density. Genetics have always been thought to be linked to breast density, but newer research suggests that poor air quality may be also be a contributing factor.
Dr. Lusine Yaghjyan and a team from the University of Florida evaluated the mammogram records of nearly 280,000 women aged 40 and older. The researchers first classified the women’s breasts as either dense or fatty, using objective standard definitions.
The investigators then evaluated the women’s geographical residence and how polluted the areas were to arrive at risk calculations.
Dr. Yaghjyan, an assistant professor of epidemiology states that, “It appears that women who have dense breasts have a 20% greater likelihood of having been exposed to smog.” Women with less dense breasts in the study were 12% less likely to have been exposed to air pollution.
The reason may be because of the chemicals that are present within the fine particles of air pollution. These may be disruptive to normal endocrine function, altering estrogen activity which may trigger proliferation (growth) of breast cells.
"Living in areas with poor air quality certainly presents risk for a number of adverse health consequences," says Peggy Reynolds, the senior research scientist at the Cancer Prevention Institute of California. It's crucial to understand the consequences better and to see continued public policy efforts to improve air quality, she added.
Both Reynolds and Yaghjyan agree that it's too soon to make any recommendations to women living in heavily polluted areas about how to reduce their potential breast cancer risk based on this initial study that only proves association and not causality.
However, if you do live in an area with poor air quality, you may want to add simple lifestyle changes that help reduce your risk of developing breast cancer, such as losing weight if you are overweight, eating a low-fat plant-based diet, and getting at least 30 minutes of exercise daily.
Yaghjyan, L et al. Association between air pollution and mammographic breast density in the Breast Cancer Surveillance Consortium. Breast Cancer Research 2017, Published April 6 2017.
Susan G Komen Foundation
By Zakysant at the German language Wikipedia, CC BY-SA 3.0, via Wikimedia Commons