High-turnover osteopenia in preterm infants: determination of urinary pyridinium cross-links of collagen

Metabolism. 1998 Mar;47(3):333-5. doi: 10.1016/s0026-0495(98)90266-9.


Osteopenia is a frequent condition in preterm infants, but its pathogenesis is uncertain. In the present study, we measured longitudinal changes in the excretion of pyridinium cross-links of collagen (specific markers of bone resorption) and evaluated the relationship between collagen cross-links and other indexes of bone and renal function in preterm infants. In these infants, urinary collagen cross-links were markedly increased on day 7 and day 30 of life and at estimated full-term gestation. The values were several times higher than those of older children and almost comparable to those of healthy full-term infants. Cross-link excretion did not correlate with beta2-microglobulin (B2M) or N-acetyl-beta-D-glucosaminidase (NAG) activity (markers of renal function), indicating that cross-link excretion is not influenced directly by infantile renal function. High serum osteocalcin and low bone mineral density (BMD) in the lumbar spine were also observed at estimated full-term gestation. There was no significant correlation between collagen cross-link excretion and either serum osteocalcin or spine BMD. We conclude that a state of high bone turnover underlies the development of osteopenia in preterm infants.

MeSH terms

  • Aging
  • Amino Acids / urine*
  • Bone Density
  • Bone Diseases, Metabolic / etiology
  • Bone Diseases, Metabolic / urine*
  • Bone Remodeling*
  • Collagen / urine
  • Collagen Type I
  • Creatinine / urine
  • Female
  • Gestational Age
  • Humans
  • Infant, Newborn
  • Infant, Premature / urine*
  • Male
  • Peptides / urine


  • Amino Acids
  • Collagen Type I
  • Peptides
  • collagen type I trimeric cross-linked peptide
  • pyridinoline
  • deoxypyridinoline
  • Collagen
  • Creatinine