Relationship between serum vitamin D levels and clinical features of acute bronchiolitis

급성세기관지염과 혈청 비타민 D와의 상관관계

Purpose: Vitamin D plays an important role in calcium homeostasis and bone metabolism. It is associated with various diseases such as cardiovascular, immune, allergic and infectious disease. The aim of this study was to investigate the difference in clinical manifestations according to the concentration of vitamin D in mild bronchiolitis. Methods: We performed a retrospective review of medical records of patients with mild bronchiolitis from November 2016 to April 2017 in Daegu Fatima Hospital. Mild bronchiolitis was classified by the modified Tal's score method. Patients were divided into 2 groups according to a 25-hydroxyvitamin D level of 20 ng/mL. We analyzed the clinical characteristics and laboratory data from the 2 groups. Results: Of the 64 patients, 19 were included in the deficiency group and 45 in the normal group. Vitamin D levels were $11.7{\pm}4.9ng/mL$ in the deficiency group and $28.8{\pm}5.0ng/mL$ in the normal group. There were no differences in clinical features between both groups. However, the vitamin D deficiency group had significantly longer hospitalization than the normal group ($6.78{\pm}2.74$ days vs. $5.3{\pm}1.7$ days, P=0.045). In the deficiency group, the incidence of previous respiratory diseases was significantly higher (P=0.001). No significant difference in blood and respiratory virus tests was observed. Conclusion: Low vitamin D levels in mild bronchiolitis were associated with longer hospitalization and prior respiratory disease. Vitamin D may affect the course of mild bronchiolitis.