People with Gum disease at increased risk of developing RA

People with increased levels of gum disease are at risk of developing rheumatoid arthritis (RA), according to the results of a study presented at the Annual European Congress of Rheumatology (EULAR 2018).

The study found that the prevalence of gum disease is increased in patients with RA and could be a key initiator of RA-related autoimmunity. The researchers explained the reason that this is because autoimmunity in RA is characterized by an antibody response to citrullinated proteins and the oral bacterium Porphyromonas gingivalis (Pg) is the only human pathogen known to express an enzyme that can generate citrullinated proteins.

"It has been shown that RA-associated antibodies, such as anti-citrullinated protein antibodies, are present well before any evidence of joint disease. This suggests they originate from a site outside of the joints," said Dr. Kulveer Mankia, the study author. He added, “Our study is the first to describe clinical periodontal disease and the relative abundance of periodontal bacteria in these at-risk individuals. Our results support the hypothesis that local inflammation at mucosal surfaces, such as the gums, in this case, may provide the primary trigger for the systemic autoimmunity seen in RA."

The study included 48 at-risk individuals (positive test for anti-citrullinated protein antibodies, musculoskeletal symptoms but no clinical synovitis), 26 patients with RA and 32 healthy controls. The three groups were balanced for age, gender and smoking. At-risk individuals underwent ultrasound assessment to assess for subclinical synovitis; only two (4%) were found to have ultrasound synovitis. Dentists examined six sites per tooth in each participant and a clinical consensus was agreed upon in each by three dentists.

DNA was isolated from the subgingival plaque, next to the gums, of each participant and used to measure the levels of three types of bacteria, Pg, Aggregatibacter actinomycetemcomitans (Aa) and Filifactor Alocis.

The results of the study showed that there was an increased abundance of both Pg and Aa in at-risk individuals. However, for at-risk individuals, only Pg was significantly increased at healthy dental sites and was associated with the overall extent of gum disease.

On the basis of the results of the study, dentists diagnosed clinical gum disease in significantly more at-risk individuals than in healthy controls (73% vs. 38%).In non-smokers, PDD and active PDD was more prevalent in at-risk individuals compared to controls.

Rheumatoid arthritis is a chronic inflammatory disease that affects a person's joints, causing pain and disability. It can also affect internal organs. Rheumatoid arthritis is more common in older people, but there is also a high prevalence in young adults, adolescents, and even children, and it affects women more frequently than men.

The study was published in the journal The Annals of Rheumatology.