Increased gain in bone mineral content of preterm infants fed an isocaloric, protein-, and mineral-enriched postdischarge formula

Preterm infants are at risk for suboptimal bone mineralization. Postnatal bone formation requires optimal nutritional composition. This study evaluated the effect of isocaloric, protein-, and mineral-enriched postdischarge formula (PDF), standard term formula (TF), and human milk (HM) on gain in bone mineral content (BMC) of preterm infants between term age (40 weeks postmenstrual age) and 6 months corrected age (CA). Between term age and 6 months CA, 93 preterm infants were randomized to be fed PDF (n = 52) or TF (n = 41) and 46 preterm infants were fed HM. Weight (g) and length (cm) were measured at birth, term age, and 6 months CA. BMC (g) was measured by whole-body dual-energy x-ray absorptiometry at term age and 6 months CA. Gain in BMC (expressed as median with interquartile range) between term age and 6 months CA was higher in PDF-fed infants (102.3 (32.4) g) compared to TF- and HM-fed infants (91.6 (24.5) and 84.5 (33.3) g, respectively), adjusted for gender, gestational age, birthweight, and gain in weight and length. Between term age and 6 months CA, isocaloric PDF enhances gain in BMC of preterm infants, independent of gain in weight and length. We speculate that higher gain in BMC during infancy may improve adult bone mass in preterm infants.