Study Suggests Oral Health & Rheumatoid Arthritis Linked

A recent study suggests poor oral health may be a precursor to rheumatoid arthritis.

A team of researchers from the University of Louisville found poor oral health can raise the risks of rheumatoid arthritis based on the presence of an enzyme found in the mouths of individual's suffering from severe gum disease. The enzyme, peptidylarginine deiminanse, has previously been associated with rheumatoid arthritis.

A separate study, presented at the 2012 European Congress of Rheumatology in Berlin, of 636 patients, each presenting with early arthritis, found:

• 24.2 per cent had 10 or fewer teeth,
• 16.1 per cent had 11 to 20 teeth,
• 36.3 per cent had 21 to 27 teeth and;
• 23.3 per cent has 28 or more teeth.

Keep in mind it takes 32 teeth, including wisdom teeth, to make up a full adult set.

What is rheumatoid arthritis?

There are many types of rheumatoid arthritis. However, simply put, it is an autoimmune disease causing pain and inflammation of the joints. With some forms of rheumatoid arthritis different organs, including the lungs, heart and eyes, can be affected. Inflammation of the joints causes a hot and aching sensation, alongside swelling, which can variably restrict movement. Permanent damage to the joints can occur, particularly if left untreated. Rheumatoid arthritis can affect the very young and old alike, but it is most common between the ages of 35 to 64. It is the second most common form of arthritis and tends to affect more women than men. It's estimated that nearly half a million Australians are RA sufferers.

Looking at the link between the RA enzyme and gum disease.

gingivalis is a bacteria found in the oral cavity. It contains the enzyme peptidyl-arginine deiminase, which is involved in a process known as citrullination.

Citrullination is the conversion of the amino acid arginine in a protein into the amino acid citrulline. When a patient has an autoimmune disease such as rheumatoid arthritis or systemic lupus, the body's autoantibodies will often attack the citrulline proteins. These citrullinated proteins are also found in the cellular debris that follows the destruction of cells in Alzheimer's disease and after smoking cigarettes. This leads researchers to believe that citrullination seems to be part and parcel with the mechanism stimulating the immune system into autoimmune disease.

“Antibodies against citrullinated proteins are known to be a specific marker [of RA] that can be detected years before the onset of the disease, and their presence and serum levels correlate strongly with disease severity,” the researchers wrote.

The autoimmune defence against the citrullinated proteins in turn produces more pain and inflammation.

Oral health and rheumatoid arthritis: a complex history

Doctors and researchers have long noted a link between poor oral health and rheumatoid arthritis. It was clearly noted that rheumatoid arthritis sufferers tended to have increased instances of periodontal disease. This, many assumed, was either because the crippling effects of RA made thorough oral hygiene difficult or that medications used to treat RA (which tend to suppress and thus compromise the body's immune response) inhibited the body's ability to fight oral bacteria and decay. Additionally, Sjögren's Syndrome with RA stopped patients from being able to produce saliva; a natural line of defence in the fight against gum disease.

However, Jerry A. Molitor, MD, PhD, associate professor in the rheumatic and autoimmune disease division of the department of medicine at the University of Minnesota, Minneapolis says the relationship is proving to be more complicated.

While research is yet to prove cause and effect, it's starting to become obvious periodontal disease doesn't always trail RA, sometimes it precedes it, says Dr. Molitor.

Dr. Molitor's own study was presented to the 2009 scientific meeting of the American College of Rheumatology in 2009. It found people with serious gum infection (periodontitis) who also tested positive for anti-CCP antibodies (the antibodies attacking the citrullinated peptides) were more likely to have moderate to severe gum disease and be a smoker. Smoking is a risk factor for both periodontitis and rheumatoid arthritis. Dr. Molitor's findings suggest RA could cause bacteria or, alternatively, that pre-existing gum disease could perhaps be triggering RA instead.

Connecting the dots between oral health and inflammatory disease.

A slew of recent studies indicate rheumatoid arthritis isn't the sole inflammatory condition with links to gum disease. Research into cardiovascular disease, chronic obstructive pulmonary disease, along with Alzheimer's and Parkinson's disease (PD), have all identified periodontitis as a possible connection.

Just exactly how they're link, and how gum disease can be utilised as a diagnostic tool for more serious conditions, is still yet to be discovered.

Take a look at our Illustrated Guide to Bone Density and Tooth Loss - Illustrated guide