Vitamin D status in very low birth weight infants and response to vitamin D intake during their NICU stays: a prospective cohort study

OBJECTIVE: To evaluate vitamin D status in very low birth weight (VLBW) infants and response to vitamin D intake. STUDY DESIGN: In this prospective cohort study of VLBW infants, 25-hydroxyvitamin D [25(OH)D] was measured regularly starting at birth. Daily vitamin D intake was estimated from parenteral and enteral sources. RESULTS: Of the included 83 infants born between November 2016 and March 2018, 44 (53%) had 25(OH)D < 30 ng/mL at birth but achieved vitamin D sufficiency (VDS) by 3 weeks while receiving 120–400 IU/day. Twenty-three (27.7%) infants had at least one 25(OH)D level >100 ng/mL during the study period. Infants whose intake was > 600 IU/day had higher prevalence of vitamin D excess (VDE). CONCLUSION: In our study, low 25(OH)D was common in VLBW infants at birth. Vitamin D intake of 120–260 IU/day from parenteral and 200–400 IU/day from enteral route was appropriate for VLBW infants to achieve VDS. Doses > 600 IU/day increased risk of VDE.