462 - Gestational Age-Dependent Vitamin D Supplementation for Preterm Infants: Should Current Practice Change to Include Customized Dosing?

Poster Number: 462
Publication Number: 462.2166

Background: Preterm infants are at high risk for vitamin D deficiency which is an important nutrient for regulating lung development and immune function. Optimal recommended daily intake of Vit D (VDI) is controversial in preterm infants with a lack of consensus globally. The American Academy of Pediatrics recommends 400 IU/d, while the European Society for Paediatric Gastroenterology Hepatology and Nutrition recommends 800-1000 IU/d. More importantly, what constitutes normal levels of 25-OH vitamin D (VDL) in preterm infants to define Vitamin D adequacy remains a source of debate; however, evidence suggests that level of < 20 ng/mL is deficient, 20-30 ng/mL is insufficient, 30-59 ng/mL is adequate and >60 ng/mL is high

Objective: To evaluate whether a daily VDI of 400 IU will achieve adequate VDL in preterm infants < 2kg and < 37 weeks gestational age (GA) and to assess the correlation of Vitamin D levels with demographic data including GA, VDI (average daily and sum total), calcium, phosphorus intake and Serum Ca, Phosphorus, alkaline phosphatase.

Design/Methods: Retrospective exploratory analysis of preterm infants < 2kg in a single center NICU who were supplemented with daily VDI of 400 IU (via feeds and supplements). Study infants were divided into 3 groups: Insufficient ( < 30 ng/mL), normal (30-59 ng/mL) and High (>60 ng/mL). Gestational age, average daily vitamin D intake and cumulative vitamin D intake were statistically compared with 25(OH)D levels using ANOVA and regression analysis.

Results: 122 infants (mean GA 30.9 + 2.4; mean BW 1515 + 499.5) were included in this study from 1/2020- 12/2022. Vitamin D levels and cumulative and mean daily VDI were analyzed at 1 month of life. 52 infants (42%) had insufficient levels, 57 (47%) had normal levels and 13 (1%) had high levels. There was a statistically significant correlation between the VDL and GA (p=0.001), average daily VDI (p=0.026), total sum VDI (p=0.018), serum alkaline phosphatase and calcium levels using ANOVA (Table 1).

Conclusion(s): Targeting a daily cumulative vitamin D intake of 400 IU achieved normal VDL in 47% of infants at 1 month. Vitamin D levels in preterm infants < 2kg in our center correlated with both GA and vitamin D intake. We acknowledge our study weakness as we do not have information on maternal vitamin D supplementation that could affect vitamin D intake via breastmilk in infants, nor did we obtain 25(OH)D levels at birth. We hypothesize that extremely preterm infants may require customized vitamin D supplementation based on GA and that future studies may benefit from obtaining a baseline vitamin D level at birth via cord blood.