Background: Recurrent aphthous stomatitis (RAS) is one of the most common oral mucosa diseases characterized by recurrent, shallow, round or oval painful oral ulcers surrounded by inflammatory erythematous halos, the condition is chronic and self-limiting in immunocompetent patients. Aim of the study: to investigate the serum vitamin D levels in Iraqi female patients with RAS and the relationship between vitamin D levels and the severity of RAS. In this cross sectional study 30 female patients with idiopathic RAS, and 30 age and sex matched healthy controls were included, the severity of RAS is assessed by the number of oral aphthous ulcers in each attack and the frequency of attacks. Serum 25(OH) D levels were determined by the Enzyme-Linked Immunosorbent Assay (ELISA) method in both RAS patients and control groups. The mean serum vitamin D (25(OH)D) levels were found to be below the normal range (< 30 ng/ml) in both the RAS patients (13.9±12.72 ng/ml) and the control (22.08 ±17.779 ng/ml) groups, with statistically significant difference between the groups (p =0.045). There was a significant correlation between the serum levels of 25(OH) D and the number of oral aphthous ulcers in each attack (r =0.435; p= 0.016).
