Preterm infants given the highest daily doses of vitamin D3 saw significant reductions in deficiency prevalence, say researchers.
Premature babies given enteral doses of 1000 IU/day of vitamin D3 saw deficiency rates drop significantly more compared with those given 400 IU/day, found researchers from the Zekai Tahir Burak Maternity Teaching Hospital, Ankara.
Baseline deficiency (defined as serum vitamin D level < 20 nanogrammes/ litre (ng/l)) prevalence was around 72% before supplementation. At 36 weeks post-menstrual age (PMA), the 1000 IU/day group had a deficiency rate of 2.5%, compared with 22.5% in the 400 IU/day group.
“Enteral supplementation of 1000 IU/d vitamin D is well tolerated and effective at increasing vitamin D concentrations and decreasing prevalence of vitamin D deficiency by 36 weeks corrected age in stable very preterm infants,” wrote first author, Ozlem Bozkurt in the study published in Early Human Development.
Previous research has established that adequate vitamin D status is important not only for satisfactory bone metabolism in infants, but also lung development, nervous system development and immune system regulation.
The study findings are important in helping to develop consensus for an optimum dosage to manage vitamin D levels in premature babies; who are born with lower vitamin D stores than full-term infants.
The randomised controlled trial involved 121 infants with gestational ages between 24 and 32 weeks. The babies were randomly assigned doses of either 400 IU/day, 800 IU/day or 1000 IU/day of enteral vitamin D3 until they were 36 weeks old.
At 36 weeks PMA, significant differences were found in deficiency levels between infants supplemented 1000 IU/day compared with those supplemented 400 IU/ day. Differences in deficiency between 1000 IU/day and 800IU/day groups were not statistically significant.
The researchers also measured other outcomes including rates of respiratory distress syndrome, bronchopulmonary dysplasia and duration of hospitalisation. No significant differences were seen among the three different groups. Researchers attributed this result to insufficient trial size.
No toxic effects arose from the supplementation, although excessive vitamin D levels (>100 (ng/l)) were seen at 36 weeks in two infants – one in the 1000IU/day group and one in the 800 IU/ day group.
The researchers did not measure effects on bone health in this trial. However, the effectiveness of supplementation in reducing deficiency levels prompted their call for further work:
“Large randomised controlled trials are needed to assess the effect of supplementation with high dose on bone metabolism and important clinical outcomes of extremely preterm infants.”
Source: Early Human Development~
Volume 112, pp 54 -59. Published online ahead of print, doi: 10.1016/j.earlhumdev.2017.07.016
“Multi-dose vitamin d supplementation in stable very preterm infants: Prospective randomized trial response to three different vitamin D supplementation doses”
Authors: Ozlem Bozkurt, Nurdan Uras, et al