title: Serum cathepsin K levels are not suitable to differentiate women with chronic bone disorders such as osteopenia and osteoporosis from healthy pre- and postmenopausal women.
abstract: OBJECTIVE
  Cathepsin K (CatK) is expressed in high levels in osteoplasts and therefore plays an important role in bone resorption. Thus CatK serum levels may be useful in the diagnosis of chronic bone disorders such as osteopenia and osteoporosis. Therefore we aimed at studying CatK levels in women putatively free of known skeletal disorders.
  
  
  METHODS
  In total, 121 voluntary women, 27 premenopausal women aged between 20 and 45 years, and 94 postmenopausal women aged 59-81 years, all free of known skeletal disorders were included. All women underwent bone density measurement, routine labor parameter and measurement of serum CatK levels.
  
  
  METHODS
  Based on WHO criteria, women were stratified in four groups (premenopausal: healthy; postmenopausal: healthy, osteopenia, osteoporosis), and their CatK levels were statistically analyzed.
  
  
  RESULTS
  Using WHO criteria 21 postmenopausal women had normal bone mineral density (BMD), 49 had osteopenia and 24 had osteoporosis. All 27 premenopausal women had normal BMD. There were no significant differences in CatK between these groups. ROC analysis resulted in poor diagnostic validity of CatK, where the area under curve was 0.544. There was no correlation neither between CatK and other biomarkers as C-telopeptide crosslaps (CTX) or bone-specific alkaline phosphatase (BAP) nor between CatK and age.
  
  
  CONCLUSIONS
  Serum levels of CatK are not suitable to differentiate women with osteoporosis from healthy subjects.
authors.affiliation: Department of Biometry and Medical Informatics, Otto-von-Guericke University, Magdeburg, Germany.
authors.forename: Daniela
authors.initials: D
authors.lastname: Adolf
authors.forename: Thomas
authors.initials: T
authors.lastname: Wex
authors.forename: Oliver
authors.initials: O
authors.lastname: Jahn
authors.forename: Christian
authors.initials: C
authors.lastname: Riebau
authors.forename: Walter
authors.initials: W
authors.lastname: Halangk
authors.forename: Silke
authors.initials: S
authors.lastname: Klose
authors.forename: Sabine
authors.initials: S
authors.lastname: Westphal
authors.forename: Holger
authors.initials: H
authors.lastname: Amthauer
authors.forename: Stephan
authors.initials: S
authors.lastname: Winckler
authors.forename: Stefan
authors.initials: S
authors.lastname: Piatek
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019540:Area Under Curve; D015415:Biomarkers / Q000097:blood; D015519:Bone Density; D001851:Bone Diseases, Metabolic / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology; D001862:Bone Resorption / Q000097:blood*; D056657:Cathepsin K / Q000097:blood*; D005260:Female; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D015663:Osteoporosis, Postmenopausal / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology; D017698:Postmenopause; D017697:Premenopause; D012372:ROC Curve; D012016:Reference Values; D055815:Young Adult
chemical_list: D015415:Biomarkers; D056657:Cathepsin K