title: Vitamin D Deficiency in Pediatric Critical Illness.
abstract: BACKGROUND
  The potential role for vitamin D in infection has been well described in adults. The objective of our study was to determine the prevalence of vitamin D insufficiency and to evaluate the relationship between vitamin D status and markers of innate immunity and infection in critically ill children.
  
  
  OBJECTIVE
  Vitamin D deficiency was highly prevalent in children with critical illness and correlated with the severity of illness and dysfunction in innate immunity.
  
  
  METHODS
  We performed a prospective clinical observational study with both case and control groups in the pediatric intensive care unit (PICU). Vitamin D status was defined as vitamin D sufficient (25-hydroxyvitamin D (25(OH)D≥ 20 ng/mL), vitamin D insufficient (25(OH)D 10 to 20 ng/mL), and vitamin D deficient (25(OH)D <10 ng/mL). Vitamin D status, severity of illness scores, and cathelicidin, and other clinical data were collected.
  
  
  RESULTS
  Sixty-one PICU patients and 46 control patients were enrolled. Over 60% of the PICU cases were found to be vitamin D insufficient while less than 1/3 of the controls were insufficient (p < 0.0001). No significant correlation was seen between plasma 25(OH)D and any severity of illness scores. Cases with asthma had a significantly lower median level 25(OH)D (16.9 ng/mL) than cases without asthma (18.7 ng/mL). Over 50% of patients hospitalized during the fall and winter were considered vitamin D deficient or insufficient whereas in the sunnier seasons (spring and summer) the prevalence of vitamin D deficiency/insufficiency decreased to about 30% (p = 0.003).
  
  
  CONCLUSIONS
  The overall finding of profound vitamin D deficiency in the pediatric critical care population is an important finding. Significant seasonal differences were noted even in the critically ill. Certain diseases like asthma in critically ill children merit further study.
authors.affiliation: Divisions of Critical Care, Department of Pediatrics, Emory University School of Medicine, and Children's Healthcare of Atlanta at Egleston.
authors.forename: Kiran B
authors.initials: KB
authors.lastname: Hebbar
authors.affiliation: Divisions of Critical Care, Department of Pediatrics, Kentucky Children's Hospital, University of Kentucky School of Medicine.
authors.forename: Michael
authors.initials: M
authors.lastname: Wittkamp
authors.affiliation: Division of Endocrinology, Metabolism & Lipids, Department of Medicine, Emory University School of Medicine and the Atlanta VA Medical Center, Decatur, GA.
authors.forename: Jessica A
authors.initials: JA
authors.lastname: Alvarez
authors.affiliation: Department of Pediatrics, Emory University School of Medicine.
authors.forename: Courtney E
authors.initials: CE
authors.lastname: McCracken
authors.affiliation: Division of Endocrinology, Metabolism & Lipids, Department of Medicine, Emory University School of Medicine and the Atlanta VA Medical Center, Decatur, GA.
authors.forename: Vin
authors.initials: V
authors.lastname: Tangpricha
keywords: LL-37; Vitamin D; cathelicidin; critical care; immunity; infection; pediatric