Periodontal disease increases breast cancer risk in postmenopausal women

Although periodontal disease has been consistently associated with chronic disease, there was only limited scientific evidence of the role of oral microbes in the development of breast cancer. Now researchers have found that postmenopausal women with periodontal disease are at a significantly increased risk of developing this cancer type.
The study included 73,737 women aged 50–79 without previous breast cancer who were originally enrolled in the Women's Health Initiative Observational Study, a prospective cohort of postmenopausal women aimed at determining risk factors to predict heart disease, cancers and fractures.


After a mean follow-up period of 6.7 years, 2,124 breast cancer cases were identified. Over 26 percent of the participants reported periodontal disease. According to the researchers, these women had a 14 percent higher risk of breast cancer compared with women without the condition. Former smokers were at an even higher risk of breast cancer. Among women who had quit smoking within the past 20 years, those with periodontal disease had a 36 percent higher risk of developing the disease. Those with periodontal disease who had never smoked or had quit more than 20 years ago had a 6 percent and 8 percent increased risk, respectively.
According to lead researcher Dr. Jo L. Freudenheim from the Department of Epidemiology and Environmental Health at the State University of New York at Buffalo, there are several possible explanations for the link between periodontal disease and breast cancer. One possibility is that systemic inflammation may arise with periodontal disease that affects the breast tissue. Another possible explanation is that bacteria from the mouth may enter the circulatory system and thereby affect breast tissue. However, further studies are needed to establish a causal link, Freudenheim said. “If we can study periodontal disease and breast cancer in other populations, and if we can do more detailed study of the characteristics of the periodontal disease, it would help us understand if there is a relationship,” she stated. “There is still much to understand about the role, if any, of oral bacteria and breast cancer.”
Breast cancer is the most common cancer in women. According to the latest statistics published by the Centers for Disease Control and Prevention, more than 220,000 women and more than 2,000 men are diagnosed with the disease each year in the U.S. alone. Periodontal disease is a common condition. It affects almost half of the adult population in the U.S. and has been shown to be associated with heart disease, stroke and diabetes.
The study, titled “Periodontal disease and breast cancer: Prospective cohort study of postmenopausal women,” was published online on Dec. 21, 2015, in the Cancer Epidemiology, Biomarkers and Prevention journal ahead of print.