Vitamin D Supplementation and T Cell Regulation in Preterm Infants: A Randomized Controlled Trial.

The objective of this study was to evaluate the effect of 2 different doses of vitamin D on the expression of T regulatory cells (Treg) in premature infants. A double-blind randomized controlled trial was conducted on preterm infants born with gestational age between 28 and 33 weeks. Subjects were randomly assigned to receive 400 or 800 IU/day of vitamin D3 when they achieved 100 mL/kg of enteral feeds. Percentage increase in Treg cell counts were measured by flow cytometry at enrollment, and after 1 and 4 weeks of oral vitamin D supplementation at the allotted doses in both groups. Short-term morbidity and mortality outcomes were also assessed. A total of 40 infants were enrolled, 20 in each group. The change in Treg count (%) was significantly less in the low-dose vitamin D3 supplementation group after 1 week (1.9 ±â€Š5.5 vs 60 ±â€Š5.6, P = 0.0005) and after 4 weeks (1.8 ±â€Š5.7 vs 73.7 ±â€Š5.6, P = 0.0028). The 2 groups did not differ in anthropometric measurements, duration of oxygen and respiratory support, and mortality. Length of hospital stay was longer in the low-dose group (24.9 ±â€Š5.14 vs 22 ±â€Š3.49, P = 0.04). Oral vitamin D supplementation has a dose and time dependent effect on percentage of Treg in infants born prematurely. The 800 IU dose of vitamin D3 did not have apparent short-term side effects. Larger studies are needed to explore the effect of vitamin D3 dosing on length of hospital stay.

Mediators in Preterm Infants With Late-onset Sepsis: A Randomized Controlled Trial.

OBJECTIVE: To evaluate biochemical and clinical effects of 2 different doses of vitamin D supplementation in preterm infants with late-onset sepsis (LOS). STUDY DESIGN: A double blinded randomized controlled stratified trial included preterm infants with gestational age (GA) ≥28 weeks with LOS. Subjects were randomly assigned to receive 400 or 800 IU/day of vitamin D3. Serum concentrations of 25(OH)D, TNF-α, and IL-6 were measured at enrollment, 7 days after vitamin D supplementation, and at 40 weeks of postmenstrual age (PMA). Short-term outcomes and growth parameters were assessed. RESULTS: A total of 50 infants were enrolled, 25 in each group. Seventy-six percentage of enrolled infants were vitamin D-deficient at enrollment in both groups whereas only one infant in the 400 IU and none in the 800 IU group remained deficient at 40 week's PMA; vitamin D concentrations at 40 weeks PMA were 54.8 ±â€Š35.1 and 67.4 ±â€Š37.1 ng/mL, respectively, P = 0.01). None of the infants enrolled in the study had signs of vitamin D toxicity. Serum pro-inflammatory cytokines IL-6 and TNF- α concentrations decreased at 1 week and at discharge in both groups without differences between groups. The 2 groups did not differ in anthropometric measurements, duration of oxygen and respiratory support, duration of antimicrobial use, length of hospital stay, and mortality. CONCLUSIONS: A dose of 400 IU of vitamin D was adequate to treat vitamin D deficiency in the majority of premature infants with LOS. The 2 dosing regimens did not differ in clinical or biochemical changes.