People in South Korea who were diagnosed with recurrent aphthous stomatitis (RAS) were at a much greater risk for developing several autoimmune diseases, according to a study published on October 3 in Oral Diseases.
Patients with recurring mouth ulcers faced a significantly higher risk of developing Behcet's disease, systemic lupus erythematosus, ankylosing spondylitis, gout, Hashimoto thyroiditis, Graves' disease, and rheumatoid arthritis, according to the authors.
"RAS like lesion may be an early sign of systemic autoimmune disease," wrote the group, led by Dr. Young Chan Lee of the School of Medicine at Kyung Hee University in Seoul.
Ordinary condition, extraordinary consequences
Recurrent aphthous stomatitis is the most common chronic inflammatory disease that occurs inside the mouth, affecting up to 25% of people depending on the population. Though the direct cause of these mouth ulcers isn't fully understood, they likely are linked to infections, allergies, systemic disease, hormonal abnormalities, and genetic factors. Evidence has revealed that immune dysfunction promotes the development of these sores, possibly due to oral epithelial damage as T cell-mediated immune response. Nevertheless, the recurrence of oral aphthous-like ulcers may be an indicator of other systemic diseases and, in many cases, is a sign of systemic autoimmune or inflammatory disorders.
The researchers used the Korean National Health Insurance claims database to analyze information from approximately 9,300 patients between 2005 and 2007. Half of them were diagnosed with recurrent aphthous stomatitis and had at least three episodes of ulcers, and the rest didn't experience them. The patients were observed during a follow-up period from 2008 to 2015, and those who received autoimmune disease diagnoses during follow-up were identified.
A glance at the numbers
The risk of all autoimmune diseases increased dramatically in those who were diagnosed with recurring mouth ulcers. Among the patients with stomatitis, 1,433 had autoimmune disease, compared with 1,168 in the control group. The risk of having two or more autoimmune diseases also was much higher in those who had recurrent aphthous stomatitis. Among those with stomatitis, 425 had two or more autoimmune diseases, compared with 255 in the control group.
Of the 14 autoimmune diseases analyzed, the data showed participants were more likely to develop seven of the diseases if they routinely experienced aphthous-like ulcers.
Behcet's disease showed the highest risk increase, with a hazard ratio of 31.16. Systemic lupus erythematosus had a hazard ratio of 1.74 and ankylosing spondylitis and gout had ratios of 1.47, according to the authors. The hazard ratio was 1.42 for Hashimoto thyroiditis and 1.37 for Graves' disease, and rheumatoid arthritis had the lowest, at 1.19.
A few flaws
The study had some limitations, including the potential for diagnostic inaccuracy, despite a well-defined population of RAS patients. Recurring mouth ulcers have no diagnostic criteria and require a doctor to diagnose them based on clinical findings. Therefore, it is possible that an oral lesion could be an ulcer that is not an aphthous ulcer, they wrote.
Knowing the potential link between recurrent aphthous stomatitis and autoimmune diseases can affect patient treatment plans and outcomes.
"RAS was associated with an increased risk of several autoimmune diseases in the Korean population," the authors concluded.
