Anxiety and small intestinal bacterial overgrowth: associations with recurrent aphthous ulcers

Recurrent aphthous ulcer (RAU) is the most prevalent oral mucosal disease, yet its etiology remains unclear. Anxiety and depression have been linked to the onset of RAU, but research findings were contradictory. The association of intestinal diseases with RAU implies a potential role of gut microbiota in the development of this condition. This study aims to explore the correlation between the presence and severity of RAU and psychological factors, as well as gut microbiota dysbiosis.

The Zung's self-rating anxiety scale (SAS), Zung's self-rating depression scale (SDS), and Pittsburgh sleep quality index (PSQI) were used to assess the participants' psychological status. The lactulose hydrogen-methane breath test was performed to detect the presence of small intestinal bacterial overgrowth (SIBO) in RAU patients. The long-term severity of RAU is quantified using the monthly number of ulcers. Compare the differences in outcomes between individuals with RAU and the healthy population, and explore the factors influencing the severity of RAU.

Forty-nine patients and 49 controls were included. The RAU group had significantly higher SAS scores (t = 2.18, p = 0.034), and SIBO positivity (χ² = 75.67, p < 0.001). Factors correlated with the monthly number of ulcers included SAS score (r = 0.52, p < 0.001), symptoms of anxiety (r = 0.42, p = 0.004), SDS score (r = 0.46, p = 0.002), PSQI score (r = 0.35, p = 0.020), and SIBO positivity (r = 0.42, p = 0.005). Multiple linear regression analyses indicated that anxiety and SIBO may influence the severity of RAU. Moreover, SAS score (r = 0.38, p = 0.010) and SDS score (r = 0.38, p = 0.009) exhibited correlations with SIBO.

RAU patients are at a higher risk of anxiety and gut microbiota dysbiosis, which could potentially escalate the severity of RAU. The role of the brain-gut axis in the pathogenesis of RAU warrants further exploration.