Periodontal (gum) disease is a common condition that has been associated with heart disease, stroke and diabetes. Previous research has found links between periodontal disease and a number of cancers, so researchers wanted to see if there was any relationship with breast cancer.
They monitored 73,737 postmenopausal women enrolled in the Women’s Health Initiative Observational Study, none of whom had previous breast cancer. Periodontal disease was reported in 26.1% of the women. Because prior studies have shown that the effects of periodontal disease vary depending on whether a person smokes or not, researchers examined the associations by smoking status.
After a mean follow-up time of 6.7 years, 2,124 women were diagnosed with breast cancer. The researchers found that among all women, the risk of breast cancer was 14% higher in women who had periodontal disease.
Among women who had quit smoking within the past 20 years, those with periodontal disease had a 36% higher risk of breast cancer. Women who were smoking at the time of the study had a 32% higher risk if they had periodontal disease, but the association was not statistically significant. Those who had never smoked or had quit more than 20 years ago had a 6% and 8% increased risk, respectively, if they had periodontal disease.
One possible explanation for the link between periodontal disease and breast cancer is that those bacteria enter the body’s circulation and ultimately affect breast tissue. However, further studies are needed to establish a causal link.