BUFFALO, N.Y., Dec. 21 (UPI) -- Postmenopausal women with gum disease are more likely to develop breast cancer, and face increased risk if they have a history of smoking, according to a new study.
Previous research has linked periodontal disease to heart disease, stroke and diabetes -- as well as oral, esophageal, head, neck, pancreatic, and lung cancers -- inspiring researchers to investigate the potential link to breast cancer as well.
The effects of smoking on gum disease have been shown in several previous studies as well, researchers said, which led to expectations for smoking history to have an effect on the risk.
"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," said Dr. Jo Freudenheim, a professor at the University at Buffalo, in a press release. "There is still much to understand about the role, if any, of oral bacteria and breast cancer."
The researchers reviewed health records for 73,737 women without breast cancer who'd been followed as part of the Women's Health Initiative Observational Study. Of the women, 26.1 percent had gum disease.
After a mean follow-up of 6.7 years, researchers found 2,124 were diagnosed with breast cancer. The researchers reported breast cancer risk was 14 percent higher among women with gum disease.
Women with gum disease who had never smoked, or quit smoking more than 20 years before the study, had a 6 and 8 percent higher risk of breast cancer. Women with gum disease who had quit smoking in the previous 20 years had a 36 percent higher risk of breast cancer, and women who were smoking at the time of the study had a 32 percent higher risk.
The researchers said the long-term influence of smoking, even if a person has quit, is well known because of changes to bacteria that have been seen in current and former smokers.