BONE DEMINERALIZATION IN CYSTIC-FIBROSIS - EVIDENCE OF IMBALANCE BETWEEN BONE-FORMATION AND DEGRADATION

Bone turnover, collagen metabolism, and bone mineral status were inves tigated in 59 patients with cystic fibrosis and in 72 sex- and age-mat ched control subjects. In all patients and control subjects serum conc entrations of osteocalcin (OC), carboxyterminal propeptide of type I p rocollagen (PICP), amino-terminal propeptide of type III procollagen ( PIIINP), and cross-linked carboxy-terminal telopeptide of type I colla gen (ICTP), and urinary values of cross-linked N-telopeptides of type I collagen (NTX), as well as total body bone mineral content (TBBM) we re measured. Higher ICTP (mu g/L) and NTX (bone collagen equivalent/ur inary creatinine (nmol/mmol) values were found in prepubertal, puberta l, and young adult patients than in control subjects (ICTP: 15.4 +/- 2 .1 and 13.2 +/- 1.8, p < 0.001; 23.3 +/- 5.3 and 20.1 +/- 4.1, p < 0.0 2; 4.8 +/- 1.1 and 4.0 +/- 1.0, p < 0.05, respectively; NTX: 1047.5 +/ - 528.6 and 227.8 +/- 71.8,p < 0.01; 997.8 +/- 391.7 and 376.3 +/- 91. 0, p < 0.01; 993.2 +/- 398.0 and 73.9 +/- 28.5, p < 0.01, respectively ). Lower OC and PICP levels (mu g/L) were showed in pubertal patients in comparison with control subjects (OC: 20.2 +/- 12.3 and 39.0 +/- 15 .1, p < 0.01; PICP: 305.8 +/- 130.4 and 436.2 +/- 110.1, p < 0.02, res pectively). Lower OC and higher PIIINP levels (mu g/L) were found in y oung adult patients than in control subjects (OC: 4.4 +/- 3.0 and 7.0 +/- 3.1, p < 0.05; PIIINP: 4.8 +/- 1.1 and 3.1 +/- 1.0, p < 0.001, res pectively). TBBM (z score) was reduced in prepubertal, pubertal, and y oung adult patients (-0.8 +/- 0.4, -1.0 +/- 0.4, -1.1 +/- 0.5, respect ively). Patients with cystic fibrosis have bone demineralization and i mbalance between bone formation and degradation.