Severe gum disease may increase the risk of developing colorectal cancer.

In a study published in the journal Cancer Prevention Research, Mingyang Song, MD, ScD, an assistant professor of clinical epidemiology and nutrition at the Harvard T.H. Chan School of Public Health, and colleagues found that people with periodontitis, the most severe form of periodontal disease, were 17% more likely to have a history of polyps and 11% more likely to have a history of benign tumors known as adenomas.

These growths on the lining of the colon are precursors to colorectal cancer, the fourth most common cancer diagnosed in the United States, which kills more than 50,000 Americans every year. 

About half (47%) of American adults have gum disease, known as periodontal disease. Most cases are mild, but 8.5% have the more serious condition known as periodontitis, which can lead to tooth loss.

The researchers also found that the odds of developing either polyps or adenomas increased with each tooth lost to the disease. Of the 42,486 people who enrolled in the study, those who had lost one to three teeth were 28% more likely to develop conventional adenomas, while those who had lost four or more teeth were 36% more likely to develop adenomas and 20% more likely to develop serrated polyps. 

“Having ever been diagnosed with periodontal disease puts a person at risk of colorectal cancer precursor lesions, some of which may eventually lead to colorectal cancer,” Song told the website Onco’Zine, adding that the results demonstrate the importance of getting screened regularly and maintaining good oral hygiene. 

Though previous studies have explored the relationship between periodontal disease and a variety of cancers, including breast, head, neck and pancreatic cancers, this study is the first to provide clinical evidence of a link between periodontal disease and colorectal cancer.

How could gum disease increase cancer risk? One hypothesis is that some of the pathogenic bacteria produced in the mouth can migrate to major organs such as the colon. In earlier research at NYU Langone, researchers found that two strains of oral bacteria known to cause periodontal disease, Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans, are associated with an increase in pancreatic cancer risk.

Interested in learning more about colorectal cancer risk factors? Click here and here to read about how your dietary habits affect your chances of developing colorectal cancer. And to learn how to reduce your risk, click here, here and here.