BONE-RESORPTION RATES IN CHILDREN MONITORED BY THE URINARY ASSAY OF COLLAGEN TYPE-1 CROSS-LINKED PEPTIDES

When bone is resorbed, cross-linking amino acids from collagen type I( pyridinolines) are excreted in the urine as small peptides. The purpos e of this cross-sectional study was to measure the urinary excretion o f type I collagen bone degradation products in children and to correla te the results with growth velocity on a population basis. Spot urines from 1076 children and 24 adults were analyzed. The concentrations of cross-linked N-telopeptides of collage type I were measured using a n ew monoclonal antibody-based microtiter-plate assay, and normalized to creatinine. Age-related changes in cross-link excretion mirrored publ ished standard growth velocity rates for males and females. The correl ation coefficient between growth rates and cross-link excretion was 0. 91. These results encourage more definitive longitudinal studies where growth rates and collagen cross-link excretion are correlated on an i ndividual-patient basis.