The surprising connection between your environment and breast cancer
Every year in the United States, 245,000 cases of breast cancer are diagnosed in women and about 2,200 in men (1). This translates to 1 in 8 women being diagnosed with breast cancer in their lifetime. This makes breast cancer the most commonly diagnosed cancer in women in the United States.
While we have found many risk factors for breast cancer like late menopause, having children late in life, and family history, we still do not know what causes normal cells to become cancerous (2). In fact, the risk factors described above only account for 30% of women with breast cancer. This means that seventy percent of breast cancer cases have no known risk factors (3).
Scientists agree that breast cancer manifests from a combination of genetic, hormonal, and environmental factors. While genetic and hormonal factors are harder to change, we may be able to reduce our risk of breast cancer by avoiding exposure to certain chemicals.
How the Environment is Linked to Breast Cancer
It has been shown that Japanese immigrants in the United States have higher incidence rates of breast cancer compared to their counterparts in their homeland (4). This observation suggests that there is a strong relationship between the disease and the environment. This is not only true in Japan! Non-industrialized countries have lower breast cancer rates than industrialized countries. People who immigrated to industrialized countries, such as the United States, from their homeland developed the same rates of breast cancer observed in their new home.
So what is going on in industrialized countries? A study investigated the link between breast cancer and the environment, and found that women who lived in areas of higher airborne lead, mercury, and cadmium were at a higher risk of developing postmenopausal breast cancer (5). Studies also found that estrogen is a key hormone that is intimately linked to the development of breast cancer, and that xenohormones, a group of synthetic chemicals that imitate estrogen, have been found to significantly enhance the risk for breast cancer during growth and adolescence (6). Xenohormones can be found in our everyday life. They are present in common weed killers, pesticides, plastics, and bug sprays. Increased exposure to these chemicals may play a role in the high risk of breast cancer seen in industrialized countries.
What You Can Do to Lower Your Risk
While scientists are still hard at work to determine the cocktail of factors that causes breast cancer, we can do our part to take precautions against the environmental factors that have been associated with the disease. When possible, avoid areas of high air pollution. Opt to stay indoors or wear a N95 face mask if conditions are poor and you must go outside. Additionally, be aware of xenohormones and other endocrine disruptors in the products you are in contact with.
- Centers for Disease Control and Prevention - Breast Cancer Basic Information