Methods: Healthy children with no co-morbidities presenting within 72 hours of bronchiolitis onset were prospectively enrolled. Viral etiologies were determined by nucleic acid amplification testing of nasopharyngeal specimens. Demographics, severity markers, and symptom severity were recorded, and parents completed a daily diary scoring symptom severity. 25-OH Vitamin D levels were obtained on enrollment. Vitamin D status was categorized as sufficient (>30 ng/mL), insufficient (<30 ng/mL) or deficient (<15 ng/ml).
Results: We enrolled 100 subjects between 2014-15. Of these, 6% were outpatients, 22% were admitted to the PICU, and 72% were on the medical ward. Mean age was 8m (SD=9m), with 42% female. Vitamin D was <30ng/ml in 63% and <15ng/ml in 21%. On multivariate analysis, younger age and breastfed status were both risk factors for Vitamin D deficiency and insufficiency (p<.05 for both). Subjects with levels <30ng/ml were more likely to be RSV infected (p=.006). Several severity measures were significantly worse in children with levels <30ng/ml, including antibiotic use, need for intravenous fluid, PICU admission, complications, level of oxygen supplementation, duration of hospitalization, and duration of oxygenation (p values for all at least <.05). On multivariate analysis adjusting for age and breastfed status, infants <30ng/ml had significantly increased odds ratios for hospital stay, duration of oxygen use and level of oxygen supplementation compared to those >30.
Conclusion: Infants with Vitamin D insufficiency had more severe bronchiolitis compared to infants who were sufficient. Younger age and breastfed status were important risk factors for insufficiency. If further studies confirm that Vitamin D insufficiency causes severe bronchiolitis, supplementing pregnant women with Vitamin D might be a strategy to reduce disease in infants.
W. J. Chen, None
M. Pugh, None
M. Ridore, None
J. Arnold, None
E. Millar, None