The Link Between Gum Disease and RA
When your dentist reminds you to floss, they may be improving your orthopedic well being, along with your oral health. New research published in Science Translational Medicine discovered that the bacteria behind gum disease could also be the catalyst behind rheumatoid arthritis (RA). Although about 1.3 to 1.5 million Americans suffer from RA, an autoimmune condition which causes inflammation, swelling, pain, and stiffness in the joints and can necessitate joint replacement surgery, the root cause is unknown.
The relationship between gum disease and RA has been explored in the past. In 2008, a German study that appeared in the Journal of Periodontology found that people with RA are eight times more likely to develop gum disease than people without RA. In 2012, researchers discovered a correlation between tooth loss and joint inflammation — the greater the tooth loss, the greater the joint inflammation. Various other studies looked at different types of bacteria, such as that responsible for periodontal disease, to try and find a connection, though this research probes further at what specific strain of bacteria could link the two issues.
An international group of researchers collected blood samples from 100 people with gum disease and 100 people with healthy gums to study the bacteria at play. They also gathered blood and joint fluid samples from over 200 people who met RA’s disease criteria, and fluid from between the gum and teeth from nine people with periodontitis and eight people without. By testing and comparing the samples, the researchers noted that those with gum disease had higher levels of citrullinated proteins in their gum fluid than normal. While citrullination is a natural protein regulatory process, the scientists discovered that a strain of bacteria called Aggregatibacter actinomycetemcomitans was responsible as it produces a toxin that splits open certain cells, releasing citrullinated proteins.
The immune system in patients with RA reacts to this by creating antibodies specifically designed to combat the toxin, suggesting that the bacteria could trigger the autoimmunity of RA. While more research is needed to find a definitive correlation, researchers from Case Western University noticed that patients with RA saw a decrease in pain and other arthritis symptoms when they treated their gum disease.
This still doesn’t provide an exact answer of what can cause RA, nor does it prove gum disease is the main culprit since the presence of one doesn’t necessarily guarantee the other. As the disease’s onset can take decades, it’s possible there are other inflammatory processes at play and poor brushing habits can’t be blamed entirely. However, these findings provide new understanding of how the disease works and interacts with other bodily systems.