Correlation between Serum Vitamin D Levels and Allergic Rhinitis Severity at Vajira Hospital: A Cross-Sectional Study

OBJECTIVE: Vitamin D affects the immune system and inflammatory process, and its deficiency is significantly associated with an increased prevalence of allergic rhinitis (AR). Therefore, the correlation between the serum 25-hydroxyvitamin D levels and the severity of AR symptoms must be investigated.METHODS: This research utilized a cross-sectional approach, focusing on patients aged 18 years and above diagnosed with AR at the Vajira Hospital, Navamindradhiraj University, Bangkok, Thailand from August 15, 2023, to January 15, 2024. The relationship between AR severity and serum vitamin D levels was analyzed using Pearson correlation coefficient. AR severity on symptoms and quality of life was assessed using the Thai version of Sinonasal Outcome Test-22 (SNOT-22) and Rhinoconjunctivitis Quality of Life questionnaire-36 (RCQ-36) questionnaires. Serum-specific immunoglobulin E (IgE) and total IgE levels were also measured to examine their relationship with the serum vitamin D level.RESULTS: Among the 58 participants, 34 (58.60%) had vitamin D deficiency. These individuals with vitamin D deficiency exhibited significantly higher AR severity compared with those without vitamin D deficiency. The mean difference between these groups was 21.90 points for SNOT-22 scores (95%CI: 17.71–26.69, p-value < 0.001) and 19.17 points for RCQ-36 scores (95%CI: 12.08–27.34, p-value < 0.001). Further analysis revealed a significant inverse correlation between serum vitamin D level and AR severity, with Pearson correlation coefficients of −0.72 for RCQ-36 (95%CI: −0.82 to −0.56, p-value < 0.001) and 0.80 for SNOT-22 (95%CI: −0.88 to −0.68, p-value < 0.001). No correlation with serum vitamin D level was found for serum-specific IgE and total IgE levels.CONCLUSION: A significant inverse relationship existed between serum vitamin D levels and AR severity. No correlation with serum vitamin D level was found for serum-specific IgE and total IgE levels.