Serum 25 Hydroxy Vitamin D Levels in Very Low Birth Weight Infants Receiving Oral Vitamin D Supplementation

Background and Objective: Vitamin D supplementation in preterm infants has been recommended by American Academy of Pediatrics (AAP); however, its efficacy and safety has not been well studied. To study 25‐hydroxy vitamin D (25OHD) levels as a marker of vitamin D status of very low birth weight infants while on vitamin D supplementation during neonatal intensive care unit hospitalization. Methods: Retrospective study of preterm infants with birth weight <1500 g admitted to our unit from January 2013 to December 2015 who were on oral vitamin D 3 400 IU supplementation. Serum 25OHD level were checked at 4, 8, and 12 weeks of age or before discharge and the levels were stratified as deficient <20 ng/mL, insufficient 20 to 29 ng/mL, normal 30 to 60 ng/mL, high 61 to 100 ng/mL and very high >100 ng/mL. Results: A total of 301 infants were enrolled, 186 very low birth weight (VLBW; 1000–1499 g) infants and 115 extremely low birth weight (ELBW; <1000 g) infants. Approximately 80% of both VLBWs and ELBWs had deficient or insufficient 25OHD levels at 4 weeks of age. On oral vitamin D supplementation, VLBW infants increased their 25OHD levels significantly by 8 and 12 weeks of age, whereas ELBW infants lagged behind at 8 weeks and increased their 25OHD levels by 12 weeks of age. Conclusions: Eighty percent of ELBW and VLBW infants have either deficient or insufficient vitamin D status at 4 weeks of age. Vitamin D supplementation helps in improving the vitamin D levels, VLBW infants significantly more than ELBW infants. AAP recommendation appears to be safe; however, if using higher supplement dosing, 25OHD level should be monitored to avoid high and very high vitamin D levels.