647 - Routine Enteral Zinc Supplementation at Full Enteral Feeds for One Month Reduces Osteopenia and Postnatal Growth Restriction in Very Low Birth Weight Infants

Publication Number: 1624.647

Alexandra Wilson, Advocate Children's Hospital - Oak Lawn, Northfield, IL, United States; April Jones, Advocate Children's Hospital - Oak Lawn, Oak lawn, IL, United States

Background: Metabolic bone disease (MBD) and postnatal growth restriction (PNGR) affect over 50% of very low birth weight (VLBW; < 1500 g) infants. Zinc is essential for osteoblast proliferation, alkaline phosphatase (ALP) activity, and linear growth. Deficiency impairs bone mineralization and weight gain velocity. In 2022, our Level III NICU implemented routine enteral zinc (1 mg/kg/day at achievement of full enteral feeds for 30 days) alongside reactive calcium/phosphorus supplementation (triggered by serum phosphorus < 5 mg/dL or ALP >500 IU/L).

Objective: To evaluate the impact of routine zinc supplementation at full enteral feeds for one month on radiographic osteopenia, bone biomarkers, and postnatal growth outcomes in VLBW infants.

Design/Methods: Retrospective before-and-after quality improvement cohort study (January 2016–October 2025). Pre-zinc era (2016–2021; n=253) vs post-zinc era (2022–2025; n=207). Inclusion: inborn VLBW infants surviving to discharge. Exclusions: major congenital anomalies, intestinal perforation, or transfer before DOL 7. Data extracted: gestational age, birth weight, feeding metrics (days to full enteral feeds, parenteral nutrition [PN] days), labs (maximum ALP, lowest PN phosphorus), growth (discharge weight z-score change [Δz]), and outcomes (osteopenia on x-ray at ≥4 weeks, fractures, PNGR severity: mild Δz 0.8–1.2, moderate 1.2–2, severe >2). Zinc compliance defined as ≥80% of 30-day course. Statistical analysis: chi-square for proportions, Student’s t-test for continuous variables; p< 0.05 significant.

Results: Cohorts were comparable (mean GA 26.4 vs 26.7 weeks; birth weight 1085 vs 1120 g). Post-zinc implementation we saw radiographic osteopenia decreased from 27.6% to 12.6% (p < 0.05), Moderate/severe PNGR declined from 50% to 29% (p < 0.05), Mean Δz-score improved from −1.5 to −0.9 (p=0.08), Days to regain birth weight fell from 9 to 6 (p < 0.05), Maximum ALP >700 IU/L trended down (14.3% to 7.7%, p=0.18), Lowest PN phosphorus improved (3.97 to 4.37 mg/dL, p=0.12). Our Necrotizing enterocolitis (NEC) rates remained stable throughout.

Conclusion(s): Routine enteral zinc (1 mg/kg/day) at full enteral feeds for one month, aligned with ESPGHAN guidelines and supported by RCTs (Itabashi 2018; Cochrane 2021), significantly reduces radiographic osteopenia and moderate-to-severe postnatal growth restriction in VLBW infants. This low-cost, high-compliance intervention improves bone health and growth trajectories without increasing NEC. Multicenter validation and long-term neurodevelopmental follow-up are recommended.