Assessment of bone turnover in term and preterm newborns at birth: Measurement of urinary collagen crosslink excretion

We measured urinary excretion of collagen crosslinks, pyridinoline and deoxypyridinoline, in term and preterm newborns at birth and evaluated the developmental changes in bone turnover. Collagen crosslink excretion in newborns was more than 10 times higher than reported adult values and several times higher than those of older children. The values were significantly higher in preterm newborns than in term newborns. In addition, a significant and inverse correlation was found between urinary collagen crosslinks and gestational age in preterm newborns. Excretion of crosslinks during this period did not correlate with beta₂-microglobulin, suggesting that the excretion was not directly influenced by renal function in newborns. We conclude that bone turnover assessed by measurement of collagen crosslink excretion is high at birth and that preterm newborns have higher bone turnover than term newborns. Copyright (C) 1999 Elsevier Science Ireland Ltd.