Evaluation of salivary nitric oxide levels and anxiety in multiple sclerosis patients, with and without Xerostomia: correlation with clinical variables

Background Xerostomia is a prevalent but often overlooked condition in multiple sclerosis (MS) patients, significantly impacting their quality of life and oral health. This cross-sectional observational study investigates the role of nitric oxide (NO) in the pathophysiology of multiple sclerosis (MS) and explores its association with xerostomia in MS patients. The primary objective was to compare salivary NO concentrations and stress levels between MS patients with and without xerostomia. Methods MS patients diagnosed by neurologists and MRI were categorized into two groups: those with xerostomia and those without. Unstimulated whole saliva samples were collected using the spitting method, and salivary NO levels were quantified using an enzyme-linked immunosorbent assay (ELISA) kit based on the Griess reaction. Stress levels were assessed using the Beck Anxiety Inventory (BAI) questionnaire. The presence of xerostomia was evaluated through the Xerostomia Inventory (XI) and clinical examinations. Results Salivary NO levels were significantly higher in MS patients without xerostomia (227.47 ng/mL) compared to those with xerostomia (102.37 ng/mL, p < 0.001). Stress levels were also notably higher in MS patients with xerostomia (17.23) versus those without (11.77, p = 0.03). A moderate negative correlation was observed between salivary NO levels and xerostomia (r = 0.44, p < 0.001), indicating that lower NO levels were associated with a higher likelihood of xerostomia. The correlation between stress levels and xerostomia was weaker but still significant (r = 0.28, p = 0.03). Multivariate binary logistic regression analysis identified salivary NO, stress levels, and age as significant predictors of xerostomia in MS patients. The logistic regression model achieved an 80% accuracy in predicting xerostomia based on salivary NO levels and stress. Conclusion This study highlights a significant negative correlation between salivary NO levels and xerostomia, suggesting that decreased salivary NO concentrations are associated with an increased risk of xerostomia in MS patients. Additionally, stress levels were positively correlated with xerostomia, indicating a potential link between higher stress and the likelihood of xerostomia in MS patients.