Although children with juvenile idiopathic arthritis (JIA) have good dental health overall, they experience more gum inflammation caused by gingivitis than do healthy children, a study found. In addition, the composition of the microbes (microbiome) in their mouth is altered compared with children who do not have JIA, the researchers found.
The study, “Oral health and plaque microbial profile in juvenile idiopathic arthritis,” was published in the journal Pediatric Rheumatology.
JIA is characterized by joint inflammation of unknown cause in children. Rheumatoid arthritis (RA) is a chronic inflammatory disease similar to JIA that occurs in adults, also affecting the joints.
Interestingly, recent studies have implicated the interplay between the microbiome — all the microbes that live in and on the human body — and the immune system in the development of RA. In particular, people with this disorder have periodontitis, also known as gum disease, which is associated with an altered oral microbiome.
A direct link between gum disease and RA has been suggested based on how rheumatoid arthritis symptoms can be controlled when gum disease is treated.
Given the commonalities between JIA and RA, and how autoimmune activation in JIA is similar to periodontitis, a team at the University of Washington sought to learn more. Thus, they assessed whether JIA patients had an altered oral microbiome and associated gum disease like those with RA.
In addition, the researchers analyzed for gingivitis, a disease that also causes gum inflammation. However, unlike the more invasive and global inflammation of periodontitis, gingivitis-caused inflammation is triggered by bacteria on the teeth that leads to local swelling and bleeding.
The study included 85 adolescents with JIA, ages 10-18 (mean age 14 years). Among the participants, 22 had oligoarticular JIA, while 17 had extended oligoarticular JIA, and 46 had polyarticular JIA. As a control group, 62 pediatric dental patients were included in the study, along with 11 healthy children who were friends of the JIA patients.
Joint exams were conducted by pediatric rheumatologists, while dental providers performed oral examinations to determine dental indices — measures of oral health — for periodontitis, gingivitis and plaque build-up. There also were probing tests for bleeding.
A parent/patient questionnaire was given to all participants to identify oral health factors such as braces, gum bleeding, jaw and tooth pain, and mouth breathing. The investigators further analyzed microbial profiles from plaque samples.
As expected, none of the participants had periodontitis, a rare condition in children. Based on indices for plaque, tooth decay, and periodontitis, the results showed a trend toward better dental hygiene in those with JIA compared with dental patients.
However, the researchers found that those with JIA had significantly higher gingivitis-associated inflammation compared with the dental patients, based on the bleeding probe tests, even after adjusting for demographic information.
The trend toward more bleeding in JIA patients compared with healthy children (the controls) was not statistically significant. Overall, no links between dental health and JIA disease activity were identified.
Microbial analysis found a more diverse population of microbes in children with JIA, with elevated numbers of bacteria genera Streptococcus, Haemophilus, and Kingella. The healthy children had higher levels of the microbes belonging to the genera Actinomyces and Corynebacterium. Similar to adults with RA, Corynebacterium were underrepresented in JIA patients.
Given the resemblance between polyarticular JIA and RA, the team then tested for similar microbial populations in people with these two diseases. Microbes belonging to the genus Porphyromonas and Rothia were more abundant in the polyarticular JIA group. In contrast, Prevotella, normally associated with RA, was lower in children with JIA.
“In this study, gingival inflammation and altered dental plaque microbial communities were associated with JIA despite overall normal oral health, and thus cannot be attributed to poor dental hygiene secondary to disability,” the scientists said.
“Understanding the role of oral pathogens in triggering and perpetuating chronic inflammation in JIA could lead to better approaches to prevention and treatment, but will require a better understanding of the immune responses to candidate oral microbes,” the team concluded.