Serial analyses of serum vitamin d-binding protein in preterm infants from birth to postconceptual maturity

Abstract

Serial measurements of vitamin D-binding protein (DBP) were made in 28 infants of 29.7 ± 2 weeks gestation and 1162 ± 344 g birthweight. Mean (±SD) values (micrograms per ml) were: cord, 375 ± 97; 1 week, 396 ± 82; 3 weeks, 382 ± 67; 6 weeks, 393 ± 78; 9 weeks, 372 ± 120; and 12 weeks, 490 ± 130. At 12 weeks of age (40–42 weeks postconceptual age), DBP, 25- hydroxyvitamin D (25OHD), calcium, phosphorus, copper, and albumin were all significantly increased (by paired t test). At this point, but not earlier, DBP was correlated with 25OHD (r = 0.69; P < 0.01) and phosphorus (r = 0.49; P < 0.05), and 25OHD was correlated with phosphorus (r = 0.48; P < 0.05) and calcium (r = 0.44; P < 0.05). This may represent a concomitant maturation of the liver’s protein synthetic abilities and the absorption and/or 25-hydroxylation in the liver of the parent vitamin D. © 1983 by The Endocrine Society.