What Is the Link Between Gum Disease and Rheumatoid Arthritis?

Periodontal disease has been associated with heart problems. Investigators have also found that such gum infections may be tied to the autoimmune condition rheumatoid arthritis. In fact, there are several warning signs that appear long before the swollen joints and excruciating pain of this disease announce themselves.

Precursors of Rheumatoid Arthritis:

Many chronic health conditions begin long before symptoms appear. The thickening of arteries leading to heart disease can develop many years before someone has a heart attack. Neurodegenerative conditions such as Alzheimer disease also create changes in the brain long before people notice cognitive impairment.

Now scientists have found early indications of rheumatoid arthritis (RA). Three to five years before people experience swollen and painful joints, they begin developing elevated levels of autoantibodies (Science Translational Medicine, Sept. 24, 2025). The authors of the study suggest that preemptive intervention in at-risk individuals might prevent or delay future tissue damage from rheumatoid arthritis.

Elevated levels of autoantibodies are sometimes linked to infections in the past. When it comes to rheumatoid arthritis, one candidate is an oral infection.

What Is the Connection with Gum Disease?

An earlier study identified a type of bacteria, Aggregatibacter actinomycetemcomitans, that provokes the immune system into overreacting in both gum disease and severe arthritis (Science Translational Medicine, Dec. 14, 2016). Doctors have long suspected a link between RA and periodontal infections, but they had not identified the responsible germ.

Protein Citrullination:

A. actinomycetemcomitans apparently puts a process called protein citrullination into overdrive. Hypercitrullination in turn signals the immune system to produce antibodies against these proteins.

Autoimmune Destruction:

The antibodies also attack the individual’s tissues and cause destruction. That is a hallmark of rheumatoid arthritis.

Not everyone with rheumatoid arthritis is infected with the bacteria that has been identified, so the researchers will now be looking for others that act in a similar manner to trigger an overactive autoimmune response. It might eventually lead to the development of medications that could kill the germs triggering the inflammation and thus stop joint destruction before it gets too far along.

Other Gum Infections That May Lead to Rheumatoid Arthritis:

A. actinomycetemcomitans is not the only oral pathogen that could be a culprit for this chronic disease. Other scientists have investigated Porphyromonas gingivalis, a common bacteria responsible for periodontitis. They found that this microbe can lead to protein citrullination, just as A. actinomycetemcomitans does (Current Opinion in Rheumatology, Sep. 2019). Subsequently, the body produces anticitrullinated protein/peptide antibodies, which are sensitive and specific indicators of rheumatoid arthritis. Perhaps dentists should become part of the primary care team, so they could alert physicians to the need for closer monitoring for chronic disease like rheumatoid arthritis.

Additional Risk Factors for RA:

Other risk factors have been identified for rheumatoid arthritis. Some research shows that people who have been exposed to mercury are more likely to develop RA. Sun exposure (and presumably the attendant vitamin D produced by sunlit skin) appears to be protective.

Rheumatoid arthritis has also been associated with inflammation of the blood vessels (Best Practice & Research. Clinical Rheumatology, Oct., 2016). We don’t know if the inflammation is caused by infection with A. actinomycetemcomitans, but infection may cause inflammation, and inflammation of blood vessels might contribute to heart trouble.

Other infections, such as Bartonella, have also been linked to rheumatoid arthriotis. You can learn more about that in our podcast. It is Show 907: Ticks, Fleas and Mystery Disease.