Normal urinary levels of telopeptide aminoterminal (NTx) of type I collagen in healthy term newborns and infants in the first month of life

: The Authors have studied urinary aminoterminal telopeptide of type I collagen (NTx), a bone catabolism marker of recent determination, by an enzyme-linked immunoassorbent assay (OSTEOMARK) in 80 urine samples of term healthy infants in the first 3 months of life. Highly significant variations have been compared in the whole period studied (P = 0.000). Levels of NTx increase significantly from 1 to 7 days of life, reaching a plateau that is kept until 45th day and then significantly decrease until 90th day, when, however, they result higher than the values reported in literature concerning older ages. The Authors conclude that even this bone catabolism marker is influenced, in the first week of life, by the particular phenomenology linked to the neonatal adaptation, and that, subsequently, shows a trend strictly linked to the bone turnover modifications throughout the faster stage of the growth.