Monitored Supplementation of Vitamin D in Preterm Infants. A Randomised Controlled Trial

Neonatal vitamin D stores at birth are dependent on maternal levels and neonates receive 50–70% of their mother’s 25-hydroxyvitamin D [25(OH)D]. The incidence of vitamin D deficiency could be up to 55% in pre term infants weighing <1000 g. The aim of this study was to assess the effectiveness of monitored supplementation of vitamin D in a population of preterm infants. Methods: Preterm infants born at 27–36 weeks of gestation were recruited within the first 7 days of life. Depending on the type of feeding, and after reaching partial enteral feeding or at 7 days of life, vitamin D supplementation of 400 IU and an additional 150–300 IU/kg was included in human milk fortifiers (if fed exclusively with breast milk) or 190 IU/kg in milk formulas. Subjects were randomised to either monitored supplementation group with an option of dose modification based on 25(OH)D levels as per protocol) or standard therapy up to 40 weeks of Post-Conceptional Age (PCA). The primary outcome measure is the number of neonates with deficiency or excess levels of 25(OH)D at 40 ±2 weeks of PCA. Additionally, 25(OH)D levels were measured at birth, 4 weeks, 8 weeks of age, and 40 +/- 2 weeks of PCA. Secondary objectives were to note incidence of osteopenia, nephrocalcinosis and nephrolithiasis. Serum parameters of calcium phosphorus and alkaline phosphatase were measured. Results: The 25 OHD levels in both groups were significantly higher at 40 weeks PCA as compared to the baseline in both groups but levels were statistically more significant in monitored group (group A) (p <0.001). 16 of the 30 infants in group B were noted to have vitamin D deficiency at 40 weeks PCA as compared to 2 in group A which was statistically significant (p <0.001). A statistically significant difference was also recorded in calcium, phosphorous and ALP values between 2 groups at 40 weeks PCA (P <0.05). No infant in the monitored supplementation group depicted metabolic bone disease of prematurity. Conclusion: The results of our study suggest that monitored vitamin D supplementation in preterm infants significantly improves 25 OHD levels and other metabolic bone parameters and decreases the risk of development of metabolic bone disease in premature infants.