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Improved linear growth after routine zinc supplementation in preterm very low birth weight infants
Tina A Seidu1,2,3, Luc P Brion3, Roy Heyne3
1Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA.
Insights
Routine enteral zinc supplementation improved linear growth in very preterm infants but did not prevent low zinc levels. Further research is needed to optimize zinc dosage and its role in preventing retinopathy of prematurity.
Area of Science:
- Neonatal nutrition
- Pediatric growth and development
- Micronutrient supplementation
Background:
- Very preterm (VPT) and very low birth weight (VLBW) infants often have suboptimal growth and nutrient status.
- Zinc (Zn) is crucial for growth and immune function in neonates.
- Current enteral zinc supplementation guidelines may not be sufficient for this vulnerable population.
Purpose of the Study:
- To compare growth, morbidity, and mortality in VPT/VLBW infants before and after implementing routine enteral zinc supplementation.
- To assess serum zinc levels and associated variables in relation to growth and clinical outcomes.
- To investigate the association between serum zinc levels and retinopathy of prematurity (ROP).
Main Methods:
- Single-center prospective cohort study of 826 VPT/VLBW infants.
- Primary outcome: change in Z-scores for length, weight, and head circumference from birth to discharge.
- Serum zinc levels were measured and analyzed in relation to gestational age, postnatal age, and clinical outcomes.
Main Results:
- Routine enteral zinc supplementation was associated with a significant increase in linear growth (Δlengthz: 0.27, P<0.001).
- Morbidity and mortality rates did not change significantly between the two epochs.
- Low serum zinc levels (<0.74 mcg/mL) were prevalent (51%) and decreased with increasing gestational and postnatal age.
- Retinopathy of prematurity (ROP) was independently associated with the lowest serum zinc levels (aOR=0.042).
Conclusions:
- Routine enteral zinc supplementation improves linear growth in VPT/VLBW infants.
- Current zinc supplementation strategies do not consistently prevent low serum zinc levels.
- Low serum zinc is a significant risk factor for ROP in preterm infants, suggesting a need to re-evaluate supplementation guidelines and explore higher dosages.
Background:
This study was designed (1) to compare growth, morbidity and mortality in < 33-week gestational age (GA) (very preterm, VPT) or very low birth weight (BW < 1500 grams, VLBW) infants before (Epoch-1) and after implementing routine enteral zinc (Zn) supplementation (Epoch-2) to meet recommendations, and (2) to assess serum Zn levels and associated variables.
Methods:
Single-center prospective cohort of 826 infants. The primary outcome was the change (Δ) in Z-scores of accurate length (Δlengthz), weight and head circumference from birth to discharge home.
Results:
In Epoch-2 vs Epoch-1 Δlengthz adjusted for confounding variables increased by 0.27 [95% confidence interval (CI) 0.13, 0.42, P < 0.001]. However, morbidity and mortality did not change. In Epoch-2 Zn decreased with GA and postnatal age: low ( < 0.74 mcg/mL) levels were observed in 51% infants. Retinopathy of prematurity (ROP) was independently associated with the lowest Zn [adjusted odds ratio 0.042 (CI 0.006, 0.306), area under the curve=0.928].
Conclusion:
Routine enteral Zn supplementation was independently associated with improved linear growth but did not prevent occurrence of low Zn. ROP was independently associated with the lowest Zn.
Implications:
Multicenter studies are needed to assess whether dosage of enteral Zn should be increased and whether Zn could help prevent ROP.
Impact:
Implementation of routine enteral zinc (Zn) supplementation was associated with improved linear growth from birth to discharge and a more frequent physiologic growth curve in preterm very low birth weight infants. Serum Zn levels decreased with gestational age and with postnatal age. Low serum Zn levels were observed frequently despite routine Zn supplementation as currently recommended, which suggests a need to re-evaluate current enteral zinc supplementation guidelines for this population. Retinopathy of prematurity among infants < 33 weeks' gestation was independently associated with low gestational age, low birthweight, stage of bronchopulmonary dysplasia and the lowest serum Zn level.
