title: Cartilage turnover assessed with a newly developed assay measuring collagen type II degradation products: influence of age, sex, menopause, hormone replacement therapy, and body mass index.
abstract: BACKGROUND
  Cartilage normally has a slow turnover but in arthritis increased metabolism results in degradation of the tissue.
  
  
  OBJECTIVE
  To assess cartilage turnover in a sample of the general population by an assay measuring cartilage derived urinary collagen type II (CTX-II) C-telopeptide degradation products.
  
  
  METHODS
  CTX-II concentrations were measured in urine samples from 615 healthy men and women aged 20-87 years, and the influence of age, sex, menopause, hormone replacement therapy (HRT), and body mass index (BMI) was assessed.
  
  
  RESULTS
  CTX-II concentrations showed age dependent variations, with notable differences between men and women. Mean (SD) CTX-II concentration in postmenopausal women (220 (118) ng/mmol, n=25) was significantly higher than in an age matched group of premenopausal women (112 (79) ng/mmol, n=26, p<0.001). CTX-II concentration in women using HRT (118 (57) ng/mmol, n=50) was significantly lower than in an age and BMI matched group of women not receiving HRT (215 (99) ng/mmol, n=50, p<0.001). In subjects with a BMI >or=25 kg/m(2), CTX-II concentrations were significantly higher than in those with a BMI <25 kg/m(2) (185 (114) v 148 (91) ng/mmol, p<0.001).
  
  
  CONCLUSIONS
  Cartilage turnover, as assessed by measuring urinary degradation products of CTX-II varies considerably with age, and significant differences between CTX-II levels in men and women as well as in pre- and postmenopausal women are found. Further studies are required to validate the marker for assessing cartilage degradation in arthritis.
authors.affiliation: Centre for Clinical and Basic Research A/S, Ballerup, Denmark. ig@ccbr.dk
authors.forename: U
authors.initials: U
authors.lastname: Mouritzen
authors.forename: S
authors.initials: S
authors.lastname: Christgau
authors.forename: H-J
authors.initials: HJ
authors.lastname: Lehmann
authors.forename: L B
authors.initials: LB
authors.lastname: Tankó
authors.forename: C
authors.initials: C
authors.lastname: Christiansen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000378:metabolism*; D015415:Biomarkers / Q000652:urine; D015992:Body Mass Index; D002358:Cartilage, Articular / Q000378:metabolism*; D003094:Collagen / Q000378:metabolism / Q000652:urine*; D024042:Collagen Type I; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D015914:Estrogen Replacement Therapy; D005260:Female; D006801:Humans; D008297:Male; D008593:Menopause / Q000378:metabolism*; D008875:Middle Aged; D010455:Peptides / Q000652:urine*; D017698:Postmenopause / Q000378:metabolism; D012016:Reference Values; D012727:Sex Characteristics
chemical_list: D015415:Biomarkers; D024042:Collagen Type I; D010455:Peptides; C052929:collagen type I trimeric cross-linked peptide; D003094:Collagen