Objectives: Bone mineralisation in preterm infants is related to the supply of calcium (Ca) and phosphorus (P). We increased the amount of minerals in parenteral nutrition (PN) for preterm infants and evaluated postnatal Ca and P metabolism in relation to mineral and vitamin D (vitD) intake.
Methods: Preterm infants, included on their first day of life, received standard PN, providing a maximum Ca/P intake of 3/1.92 mmol · kg−1 · day−1 on day 3. Ca/P content of formula was 2.5/1.6 mmol/dL, and fortified human milk was 2.4/1.95 mmol/dL. PN supplied 80 IU · kg−1 · day−1 vitD. Formula and fortified human milk contained 200 IU/dL of vitD. During a 5-week period, serum concentrations and urinary excretion of Ca/P were registered and related to the intake of minerals and vitD.
Results: During 12 months, 79 infants (mean gestational age 29.8 ± 2.2 weeks, mean birth weight 1248 ± 371 g) were included. The recommended intake for minerals was achieved by day 5 and for vitD by 4 weeks. Infants developed hypercalcaemia, hypercalciuria, and hypophosphataemia during the first postnatal week, leading to the additional P supplementation in 49 infants. The renal tubular reabsorption of P was >95% until day 9 but decreased <70% after the second week. Alkaline phosphatase was normal at birth, increased to a maximum of 450 IU/L by day 14, and remained above the normal range for the remaining period.
Conclusions: Parenteral intake of P appeared to be too low, leading to mineral imbalances in the early postnatal period, and vitD intake was also below recommendations.
*Department of Paediatrics, Subdivision of Neonatology, Radboud University Medical Centre, Nijmegen
†Department of Paediatrics, Leiden University Medical Centre, Leiden
‡Department of Paediatrics, Medisch Spectrum Twente, Enschede
§Department of Paediatrics, VU University Medical Centre, Amsterdam, The Netherlands.
Address correspondence and reprint requests to Viola Christmann, Department of Paediatrics, Subdivision of Neonatology, Radboud University Medical Centre, PO Box 9101, Internal Postal Code 804, 6500 HB Nijmegen, The Netherlands (e-mail: firstname.lastname@example.org).
Received 12 November, 2013
Accepted 12 November, 2013
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J.B.G. received honoraria from HiPP GmbH & Co, is receiving grants from Danone and Mead Johnson Nutrition, received payment for lectures, including service on speakers’ bureaus, from Nestle Nutrition Institute, Baxter, Danone and Nutricia Nederland NV, and received royalties from Reed Elsevier. The other authors report no conflicts of interest.