How many times has your dentist reminded you of the importance of flossing? Well, here's additional incentive for maintaining good oral hygiene. According to a study in the June issue of Lancet Oncology, periodontal disease (more commonly referred to as gum disease) is associated with a small but statistically significant increase in cancer risk.

Previous studies have suggested a link between tooth loss or periodontal disease and cancer risk, but these reports may have been confounded by smoking, which is an independent risk factor for the development of certain cancers. In this study, investigators analyzed data from the Health Professionals Follow-Up Study (HPFS), a large questionnaire study of male health professionals between the ages of 40 and 75 who were followed over a long period of time. After examining data from 48,375 participants who were followed for an average of 17.7 years, the researchers found that men who reported a history of periodontal disease had a slightly higher number of new cancer diagnoses than men without periodontal disease. This increase in cancer risk was found in both smokers and non-smokers. The specific cancers associated with a history of periodontal disease were lung (for smokers only), kidney, pancreas, and blood-related cancers.

Although this study was limited by reporting bias (in other words, the history of periodontal disease was self-reported and not independently confirmed), further research to confirm the role of gum disease in cancer may be important, especially because periodontal disease can be treated.