[Normal levels of collagen-type-I telopeptide in the first 90 days of life].

Serum levels of carboxyterminal telopeptide of type I collagen (ICTP), a marker of matrix degradation, were measured by RIA test, on 184 samples of healthy newborns and children aging from 1 (cord blood) to 90 days of life. We found ICTP values about tenfold higher than the adults', with highly significant variations (P < 0.001) in the whole period studied. During the first three months of life serum levels of the bone marker show a progressive increase from 0 to 7 days, they remain unchanged until the 30th day and then decrease until the 45th day, maintaining similar values from the 45th to the 90th day of life. The authors think that the pattern of ICTP in the first week of life is under the influence of the adapting phenomena following delivery, in which catabolic processes are predominant, while in the second period ICTP modifications are related to growing processes and then to bone turnover.