Gum disease may increase the risk of developing cancer, researchers have said.
Male health professionals with a history of gum disease in a long-running study had a 14 percent higher overall risk of developing cancer, they said.
"After controlling for smoking and other risk factors, periodontal disease was significantly associated with an increased risk of lung, kidney, pancreatic and hematological (blood) cancers," Dr Dominique Michaud of Imperial College London and colleagues wrote in the journal Lancet Oncology.
This higher overall risk persisted even in people who had never smoked.
Gum or periodontal disease is an infection of the tissues surrounding and supporting the teeth. Prior studies have suggested people with periodontal disease are more likely to develop heart disease and diabetes.
How the study was done
People with gum disease have inflammation in their blood and inflammation also has been linked with cancer. But this could simply mean that whatever causes the inflammation may also cause gum disease and cancer. Michaud and colleagues wanted to see if gum disease increases the risk of cancer.
They used data from a large study of male doctors and other health professionals aged 40 to 75. The study was started in 1986 at Harvard University.
Nearly 50 000 men filled out health surveys and were followed for more than 17 years. The survey included information on gum disease and bone loss as well as number of teeth and tooth loss.
More than 5 700 of the men developed cancer, excluding cases of non-melanoma skin cancers and non-aggressive prostate cancer. The researchers found that men who had gum disease had 14 percent higher cancer risk compared to those who did not.
The risks were higher depending on the type of cancer.
Periodontal diseases must be treated
Those with history of gum disease had a 36 percent higher risk of lung cancer, a 49 percent higher risk of kidney cancer, a 54 percent higher risk of pancreatic cancer and a 30 percent higher risk of having a blood cancer (such as non-Hodgkin lymphoma, leukaemia or multiple myeloma) compared to men who did not have a history of gum disease.
In those who never smoked, gum disease was linked with a 21 percent increase in overall cancer risk and a 35 percent higher risk of blood cancers. They found no association for lung cancer in this group.
Men who had fewer teeth (0 to 16) at the start of the study had a 70 percent higher risk of lung cancer compared with individuals with more teeth (25 to 32) at the start of the study but this may be linked with smoking.
"The increased risks noted for haematological, kidney, and pancreatic cancers need confirmation but suggest that gum disease might be a marker of a susceptible immune system or might directly affect cancer risk," Michaud said in a statement.
They said it is premature to suggest that good oral hygiene can have any effect at preventing cancer but said periodontal disease should nevertheless be treated. – (Reuters Health, May 2008)
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