Exploring the relationship between serum 25-hydroxyvitamin D levels and allergic rhinitis severity in the pediatric population.

OBJECTIVES

Recent studies have suggested that serum 25-hydroxyvitamin D3 (s25-OHD3) may modulate immune responses in allergic diseases. However, the relationship between s25-OHD3 levels, allergic rhinitis (AR) severity, and allergen sensitization remains unclear. This study aimed to investigate the association between s25-OHD3 levels and AR severity, including the potential role of allergen sensitization.

METHODS

This retrospective study, conducted at Ankara Bilkent City Hospital between 2019 and 2024, included 343 children with AR aged 2 to 18 years. Patients were evaluated for s25-OHD3 levels, allergen sensitization (via skin prick test and/or serum-specific IgE), and clinical characteristics. AR severity was classified according to Allergic Rhinitis and its Impact on Asthma (ARIA) guidelines, and clinical response to vitamin D supplementation was reassessed after 12 weeks. Risk factors for increased AR severity were identified by regression analysis.

RESULTS

The median s25-OHD3 level was 16.0 ng/mL (IQR: 10.8-22.0). An inverse correlation was observed between age and s25-OHD3 levels (rs = -0.202, p < 0.001). Lower s25-OHD3 levels were significantly associated with greater AR severity (p < 0.001). Additionally, patients with concomitant allergic diseases - particularly those with allergic conjunctivitis, asthma, and atopic dermatitis - had significantly lower s25-OHD3 levels (p = 0.004, p = 0.032, and p = 0.042, respectively). Notably, sensitization to cat dander was also associated with reduced s25-OHD3 levels (p = 0.043). Multivariable regression analysis identified lower s25-OHD3 levels, coexisting allergic conjunctivitis, pollen sensitization, and polysensitization as independent risk factors associated with increased AR severity. Furthermore, a significant reduction in AR severity was observed following vitamin D supplementation (p < 0.001).

CONCLUSION

This study underscores the impact of s25-OHD3 deficiency on the severity of AR and highlights the importance of evaluating s25-OHD3 levels in the management of pediatric AR to support the development of targeted therapeutic approaches.