Periodontal disease has been associated with an increased risk of several types of cancer in postmenopausal women, a new study published in the journal Cancer Epidemiology, Biomarkers & Prevention, a journal of the American Association for Cancer Research, revealed.

The findings applied to women who had never smoked as well as those who had.

The researchers conducted a prospective cohort study of 65,869 women aged 54- 86 who were enrolled in the Women's Health Initiative Observational Study. The women self-reported periodontal disease on questionnaires administered between 1999 and 2003. The researchers monitored cancer outcomes through September 2013. Over an average follow-up time of 8.32 years, the researchers identified 7,149 cases of cancer.

The study showed that a history of periodontal disease was associated with a 14% higher risk of developing any cancer. The strongest association was for cancer of the esophagus, which was more than three times more likely in women with periodontal disease than women who did not report periodontal disease. Lung cancer, gallbladder cancer, melanoma, and breast cancer were also associated with significantly higher risk.

The researchers noted that certain cancers, such as breast cancer, lung cancer, and gallbladder cancer, were associated with higher risk in women who smoked and had periodontal disease. Others, such as melanoma, were associated with higher risk in the women who had never smoked but did report periodontal disease.

Jean Wactawski-Wende, PhD, a professor in the Department of Epidemiology and Environmental Health and dean of the School of Public Health and Health Professions, State University of New York at Buffalo, was senior author. She said: "The esophagus is in close proximity to the oral cavity, and so periodontal pathogens may more easily gain access to and infect the esophageal mucosa and promote cancer risk at that site.”

The authors said the study's large size adds to the strength of the findings.

"This study is the first national study focused on women, particularly older women," Wactawski-Wende said. "Our study was sufficiently large and detailed enough to examine not just overall risk of cancer among older women with periodontal disease, but also to provide useful information on a number of cancer-specific sites."