Women with periodontal disease are at greater risk for developing breast cancer, according to a new study by the American Association for Cancer Research.
Periodontal disease, a common condition characterized by painful inflammation of the gums, has been previously linked to a greater risk for heart disease, stroke, and diabetes. Research also has found links between periodontal disease and oral, esophageal, head and neck, pancreatic, and lung cancers.
In the new study, the researchers wanted to determine whether the disease had any relationship with breast cancer.
A team of researchers, led by Jo L. Freudenheim, Ph.D., monitored 73,737 postmenopausal women enrolled in the Women’s Health Initiative Observational Study, none of whom had previous breast cancer.
They found that 26.1 percent of the women had periodontal disease. After an approximate follow-up time of 6.7 years, 2,124 women were diagnosed with breast cancer. The findings reveal that among all of the participants, the risk of breast cancer was 14 percent higher in those with periodontal disease.
Because prior studies have shown that the effects of periodontal disease vary depending on whether a person smokes, researchers examined the associations stratified by smoking status.
Of all the women who had quit smoking within the past 20 years, those with periodontal disease had a 36 percent higher risk of breast cancer. Women who were smoking at the time of this study had a 32 percent higher risk if they had periodontal disease, but the association was not statistically significant.
Women with no history of smoking along with those who had quit more than 20 years ago had a six percent and eight percent increased risk, respectively, if they had periodontal disease.
“We know that the bacteria in the mouths of current and former smokers who quit recently are different from those in the mouths of non-smokers,” Freudenheim explained.
One possible explanation for the association between periodontal disease and breast cancer is that those bacteria enter the body’s circulation and reach the breast tissue. However, further studies are needed to establish a causal link, Freudenheim added.
The authors acknowledge that there were some limitations to this study. Women self-reported their periodontal disease status, after being asked whether a dentist had ever told them they had it.
Furthermore, since the research involved women who were already enrolled in a long-term national health study, they were more likely than the general population to be receiving regular medical and dental care, and were likely to be more health-conscious as well.