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Low vitamin D status may make sick children more ill

August 15, 2012

Vitamin D deficiency is common among patients admitted to pediatric intensive care units (PICUs) and is associated with more severe illness, two recent studies from the US and Canada have revealed.

According to the first study, led by Kate Madden, MD, of Children’s Hospital Boston, among patients younger than 21 admitted to the hospital’s medical-surgical PICU, 40.1% had deficient levels of 25-hydroxyvitamin D (25(OH)D). Declining 25(OH)D levels were significantly associated with both worsening illness severity and increasing vasopressor use, the researchers reported. Vasopressors are compounds which cause the blood vessels to constrict.


The Boston scientists analyzed data of 511 patients (median age 5.3 years) admitted to the PICU over a one year period. The median serum level of 25(OH)D on admission was 22.5 ng/mL, and levels less than 20 ng/mL were considered deficient. Illness severity was assessed using the Pediatric Risk of Mortality III (PRISM III) score. These findings may be explained by the role of vitamin D in innate immune function and inflammation, its role in calcium homeostasis, or the findings may have been influenced by fluid shifts and dilution, Madden and colleagues concluded.


In another study using data from six different Canadian PICUs, led by James McNally, MD, PhD, of the Children's Hospital of Eastern Ontario in Ottawa, vitamin D deficiency was identified in 69% of patients younger than 18 and was associated with worsening illness severity.


McNally and colleagues, who found similar results to those found in the Boston study, examined data on 326 children and teens (median age 3.7 years). Their investigation was a secondary analysis of data and biological samples from the Adrenal Insufficiency in Pediatric Critical Illness Study (AIP). Vitamin D deficiency was independently associated with an increase of 1.92 days spent in a PICU. In addition, higher PRISM III scores on admission were associated with lower vitamin D levels, with every additional PRISM point increasing the likelihood of being vitamin D de?cient by 8%.


The findings from these studies are consistent with prior research involving critically ill adults. Nevertheless, both research groups are still calling for studies testing whether heavy vitamin D supplementation in the early stages of critical illness might improve clinical outcomes. Other scientists have commented that at a minimum, the results indicate that comprehensive efforts should be made to ensure that children receive at least the recommended daily intake of vitamin D (400 IU/day for infants, 600 IU/day for children aged >1 year). Furthermore, more should be done to find the best way of assessing or treating low serum 25(OH)D levels in a PICU setting.

References

  1. Madden K, et al. Vitamin D deficiency in critically ill children. Pediatrics 2012 (August); DOI: 10.1542/peds.2011-3328.

  2. McNally J, et al. The association of vitamin D status with pediatric critical illness. Pediatrics 2012 (August); DOI: 10.1542/peds.2011-3059.

  3. Abrams S and Coss-Bu. Vitamin D deficiency in critically ill children: a roadmap to interventional research. Pediatrics 2012 (August); DOI: 10.1542/peds.2012-1752.