title: Bone resorption levels by age and menopausal status in 5,157 women.
abstract: OBJECTIVE
  The purpose of this study was to describe bone resorption activity using a biochemical marker according to the categories of age, menopausal status, and selected drug/supplement use in middle-aged and elderly community-based women.
  
  
  METHODS
  This was a cross-sectional study that assessed urinary cross-linked N-telopeptide of type I collagen (NTx) and used self-report data to group women as premenopausal (Pre), perimenopausal (Peri), postmenopausal without hormone replacement therapy (Post), and postmenopausal with hormone replacement therapy (HRT).
  
  
  RESULTS
  Mean NTx values were found to be significantly different by group and controlling for age (p = 0.001), with post hoc tests showing all pairwise group comparisons as significantly different (p = 0.001), except that the Pre and HRT groups were not significantly different. Both the Peri and the Post NTx levels were significantly higher than the Pre and the HRT groups'. NTx values in the Peri group varied with age-the youngest Peri women were similar to Pre women, and the oldest Peri women were similar to Post women. Significantly lower NTx levels were found only in the Post (p = 0.009) and HRT (p < 0.001) groups using diuretics compared with nonuse and only in the HRT group using calcium supplements compared with nonuse (p = 0.006). No differences by thyroid use were found. With a biochemical marker, the results showed that bone resorption activity differences could be demarcated in women according to age, estimated menopausal stage, and selected drug/supplement use.
  
  
  CONCLUSIONS
  These results support the usefulness of NTx assessment for indicating bone resorption activity and therefore the potential for osteoporosis or for monitoring the efficacy of antiresorptive therapies.
authors.affiliation: Department of Biobehavioral Nursing and Health Systems, School of Nursing, University of Washington, Seattle 98195, USA.
authors.forename: L L
authors.initials: LL
authors.lastname: Lewis
authors.forename: J F
authors.initials: JF
authors.lastname: Shaver
authors.forename: N F
authors.initials: NF
authors.lastname: Woods
authors.forename: M J
authors.initials: MJ
authors.lastname: Lentz
authors.forename: K C
authors.initials: KC
authors.lastname: Cain
authors.forename: V
authors.initials: V
authors.lastname: Hertig
authors.forename: S
authors.initials: S
authors.lastname: Heidergott
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000652:urine; D003094:Collagen / Q000652:urine*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008593:Menopause / Q000502:physiology*; D008875:Middle Aged; D015663:Osteoporosis, Postmenopausal / Q000175:diagnosis; D017698:Postmenopause / Q000502:physiology*; D017697:Premenopause / Q000502:physiology*
chemical_list: D015415:Biomarkers; D003094:Collagen