Posted: Oct 20, 2009 3:57 PM
"We've known for a while that there is an association between gum disease and rheumatoid arthritis. But our new work suggests periodontal disease is causal," says study head Jerry A. Molitor, MD, PhD, associate professor in the division of rheumatology and autoimmune disease at the University of Minnesota, Minneapolis.
Compared to people with mild or no periodontitis surrounding two or three teeth, people with moderate to severe gum disease are nearly three times more likely to develop rheumatoid arthritis (RA), the study shows. Among never-smokers with moderate to severe gum disease, the risk is increased ninefold.
People with periodontitis also have higher blood levels of an antibody that has been associated with more severe, damaging RA than do people with healthy gums, Molitor says.
The study involved 6,616 people who underwent four thorough health checkups between 1987 and 1998. Everyone also had a dental exam between 1996 and 1998.
The findings were presented at the annual meeting of the American College of Rheumatology.
So why would gum disease lead to the chronic, painful inflammation of the joints that characterizes rheumatoid arthritis?
No one knows for sure. But evidence suggests the mechanism of destruction of connective tissues in both gum disease and RA is similar, researchers say.
If confirmed in future studies, the research has important implications for patients, Molitor says.
"One of the questions I get all the time from RA patients is, 'What is my kids' risk of developing it?' This suggests that in people with a family history, flossing and brushing can help to modify risk," he says.
Darcy Majka, MD, a rheumatologist at Northwestern University in Chicago who moderated a news conference to discuss the findings, tells WebMD, "This is a very important study -- the first to show [a causal relationship] between rheumatoid arthritis and periodontitis.
"Unlike heart disease, where there are a lot of modifiable risk factors, we don't have a lot of modifiable risk factors for RA," she says.
Majka's advice: "See your dentist right at the six-month mark for a checkup and practice good dental hygiene."