25(OH)D	25-Hydroxyvitamin D
AAP	American Academy of Pediatrics
ALP	Alkaline Phosphatase
CI	Confidence Interval
CRP	C-Reactive Protein
DBP	Vitamin D-Binding Protein
EDTA	Ethylenediaminetetraacetic Acid
ELISA	Enzyme-Linked Immunosorbent Assay
ESPGHAN	European Society for Paediatric Gastroenterology, Hepatology and Nutrition
GC	Group-Specific Component (Vitamin D-Binding Protein Gene)
IQR	Interquartile Range
NICU	Neonatal Intensive Care Unit
SPSS	Statistical Package for the Social Sciences
STROBE	Strengthening the Reporting of Observational Studies in Epidemiology
VIF	Variance Inflation Factor
WBC	White Blood Cell Count