The risk is a little higher—at 28 per cent—among those who have the most severe form of periodontitis, and have lost all their teeth. Lung and colorectal cancers were the two most common cancers for people with bad gums, researchers at the Johns Hopkins Bloomberg School of Public Health found.
They tracked the health of 7,466 people for more than 12 years, during which time 1,648 of them developed cancer. The researchers discovered that those with severe periodontal disease had more than double the risk of developing lung cancer compared to those with mild, or no, periodontitis. There was also a small increased risk of pancreatic cancer.
Although the researchers aren't yet sure if bacteria from bad gums cause cancer or are a by-product of the disease, one common thread seems to be smoking. Smokers are more likely to suffer from gum disease, and smoking also raises the risk for lung and colorectal disease.
Gum disease didn't seem to raise the risk for other cancers, such as breast, prostate or blood and lymphatic cancers, however.
Their findings have been supported by separate research, which found that the bacteria in the gums have also been found in colorectal cancer tissues.