title: Comparison of serum and urinary C-terminal telopeptide of type I collagen in aging, menopause and osteoporosis.
abstract: BACKGROUND
  Urinary C-terminal telopeptide of type I collagen (u-CTx) has been reported to be a sensitive biochemical marker of bone turnover. There have been two assays for urinary CTx, which are alpha-CTx and beta-CTx. A newly developed immunoassay for serum CTx (s-CTx) is now available for assessment of bone resorption. We evaluated the effects of aging, menopause, and osteoporosis on the measurements of serum CTx and compared them to urinary CTx assays.
  
  
  METHODS
  In 79 premenopausal healthy women, 80 postmenopausal healthy women, 61 osteoporotic patients with vertebral fractures and 34 osteoporotic patients with hip fractures, s-CTx and urinary beta-CTx (u-betaCTx) were measured by ELISAs, and urinary alpha-CTx (u-alphaCTx) was measured by an RIA.
  
  
  RESULTS
  In all subjects, s-CTx significantly correlated with both u-alphaCTx (r=0.54) and u-betaCTx (r=0.51). There was no significant difference among s-CTx, u-alphaCTx and u-betaCTx in the T-scores of the postmenopausal group over the premenopausal group. These findings indicate that the value of s-CTx, as well as urinary CTxs, reflected the increase of bone resorption associated with menopause with a high degree of sensitivity. Patients with vertebral fractures had moderately increased concentrations of bone resorption markers compared to age-matched healthy postmenopausal women (T-score; s-CTx: 0.8, u-alphaCTx: 0.9, u-betaCTx: 0.7), whereas bone resorption markers in hip fracture patients were greatly increased compared to healthy postmenopausal women (T-score; s-CTx: 1.1, u-alphaCTx: 1.3 u-betaCTx: 1.3). The T-scores of u-CTxs against the postmenopausal group in vertebral fracture group and in hip fracture group were not significantly different from those of s-CTx.
  
  
  CONCLUSIONS
  s-CTx, as well as urinary CTxs, reflects the increase of bone resorption in patients with vertebral fractures and hip fractures.
authors.affiliation: Department of Orthopedic Surgery, Hamamatsu University School of Medicine, 3600 Handa, Hamamatsu 431-3192, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Kawana
authors.forename: M
authors.initials: M
authors.lastname: Takahashi
authors.forename: H
authors.initials: H
authors.lastname: Hoshino
authors.forename: K
authors.initials: K
authors.lastname: Kushida
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000097:blood* / Q000473:pathology / Q000652:urine; D015415:Biomarkers / Q000097:blood / Q000652:urine; D001862:Bone Resorption / Q000097:blood / Q000652:urine; D016022:Case-Control Studies; D003094:Collagen / Q000097:blood* / Q000652:urine*; D024042:Collagen Type I; D004797:Enzyme-Linked Immunosorbent Assay / Q000592:standards; D005260:Female; D006620:Hip Fractures / Q000097:blood / Q000652:urine; D006801:Humans; D008593:Menopause / Q000097:blood* / Q000652:urine; D008875:Middle Aged; D015663:Osteoporosis, Postmenopausal / Q000097:blood* / Q000652:urine; D010455:Peptides / Q000097:blood* / Q000652:urine*; D011863:Radioimmunoassay / Q000592:standards; D011933:Reagent Kits, Diagnostic / Q000592:standards; D016103:Spinal Fractures / Q000097:blood / Q000652:urine
chemical_list: D015415:Biomarkers; D024042:Collagen Type I; D010455:Peptides; D011933:Reagent Kits, Diagnostic; C052929:collagen type I trimeric cross-linked peptide; D003094:Collagen