Vitamin D Deficiency in Children with Acute Bronchiolitis: A Prospective Cross-Sectional Case- Control Study

Objective: To evaluate serum 25(OH) vitamin D levels in infants and toddlers with acute bronchiolitis (AB), compared to subjects with non-respiratory febrile illness . Methods: : a prospective cross-sectional case-control study which compared serum 25(OH) vitamin D levels between infants and toddlers diagnosed with Acute Bronchiolitis (AB) to subjects with non-respiratory febrile illness. Results: : 127 patients aged <24 months were recruited; 80 diagnosed with AB and 47 patients with non- respiratory febrile illnesses. Both groups had similar demographics aside from age (mean of 7 months vs. 10 months in the AB group compared to control group (p=0.03)) and respiratory symptoms. Serum 25(OH) vitamin D levels were significantly lower in the bronchiolitis group; median [IQR] 28[18-52] vs. 50[25-79] nmol/L, respectively, (p=0.005). Deficient vitamin D levels (<50nmol/L) was found more frequently in AB than controls; 73% vs. 51% (p=0.028). Multivariate logistic regression, adjusted for age, sex, ethnicity and nutrition, showed vitamin D deficiency was more probable in AB patients; OR[95%CI] 3.139[1.369-7.195]. No correlation was found between serum vitamin D levels and bronchiolitis severity, which was assessed via Modified Tal Score and by length of hospital stay. Conclusion: children with acute bronchiolitis displayed significantly lower vitamin D levels than children with non-respiratory acute febrile illnesses.