132 - The Relationship between Nutrition and Bone Status Measured by Quantitative Ultrasound in Preterm Infants during the Stay in Neonatal Intensive Care Unit

Poster Number: 132
Publication Number: 132.415

Background: Preterm infants are at risk of osteopenia during growth. Previous studies have reported on the application of quantitative ultrasound (QUS) measurement of the tibial bone speed of sound (SOS) in assessing the bone status in newborn preterm infants. Although previous studies revealed the inadequate supply of nutrients (vitamin D, calcium, and phosphorus) and prolonged parenteral nutrition result in osteopenia of prematurity, there were few studies directly on the relationship between nutrition and bone status measured by quantitative ultrasound.

Objective: The aim of this study is to evaluate the relationship between nutrition and bone status measured by quantitative ultrasound in preterm Infants during their stay in the neonatal intensive care unit.

Design/Methods: Preterm infants (gestational age less than 37 weeks) admitted to the neonatal intensive care unit for more than four weeks between Nov. 2021 and Nov. 2022 were enrolled. Nutritional status, including parenteral nutrition (PN) and enteral nutrition (EN), were recorded and calculated. Bone SOS measured by QUS has been performed at the left tibia at the first, second, third, and fourth weeks. We calculated the fluid, energy, calcium, phosphate, and vitamin D level intake in both PN and EN on the day of SOS measurement.

Results: This study consisted of 138 preterm infants (72 Male, 66 Female). The mean gestational age was 31.7 weeks (SD, 3.4 weeks, range 23-36 weeks), and the mean birth weight was 1639.0 grams (SD, 564.0 grams, range 595-3100 grams). Tibial bone SOS (m/s) at first week was significantly positively correlated with gestational age (SOS at first week = 1726.5 + 35.7*gestational age, p-value < 0.0001). The lowest value of SOS is the 2nd week of age, but there was no statistical difference between the 1st and 4th week of SOS. There is a positive correlation between the first week of SOS and the other week of SOS. The analysis of the correlation among 4th week SOS and fluid, energy intake, calcium, phosphate, and vitamin D levels in both PN and EN revealed the calcium, phosphate, and vitamin D of each week are positively correlated with 4th week SOS. We also noted the day with adding vitamin D supplements by Polyvisol and duration of PN were negatively associated with lower 4th week SOS (the day adding vitamin D, r= -0.67, p-value < 0.0001; duration of PN, r=-0.61, p-value < 0.0001).

Conclusion(s): This study revealed the importance of nutritional status in the first to third week on the later bone status development in preterm infants during their stay in the neonatal intensive care unit.