title: Influence of pattern of menopausal transition on the amount of trabecular bone loss. Results from a 6-year prospective longitudinal study.
abstract: BACKGROUND
  Bone density is lower in postmenopausal than in premenopausal women. Recent findings have suggested that accelerated bone loss already begins before menopause. Despite numerous cross-sectional studies on menopause-related bone density, longitudinal data on perimenopausal bone density changes are scarce. This study sought to characterize the dynamics of changes leading to postmenopausal osteopenia and to possibly find the time point at which accelerated bone loss begins.
  
  
  METHODS
  We prospectively followed 34 pre-, peri- and early postmenopausal women without prior external hormone use, measuring their lumbar spine trabecular bone density with quantitative computer tomography at 0, 2 and 6 years. The analysis of the changes over time was done in a tri-parted fashion, since menopausal status changed variably for individual subjects: we grouped the participants according to their currently valid menopausal classification for prospective (baseline classification), interim (2 years) and retrospective (6-year classification) analysis.
  
  
  RESULTS
  Six different patterns of menopausal transition were identified in our sample. Bone loss in the groups not reaching postmenopause during 6 years of observation was >50% of the maximum bone loss observed during the study period. Invariably for all analyses, the perimenopausal phase with estrogen levels still adequate was associated with the greatest reduction of trabecular bone mineral density, reaching 6.3% loss annually in the lumbar spine. By comparison, the average rate of loss was slower in the early postmenopause; total bone loss differed by pattern of menopausal transition (one-way ANOVA p<0.05).
  
  
  CONCLUSIONS
  The presented data for the first time show the perimenopausal course of trabecular bone loss (as measured by QCT of the lumbar spine). Acceleration of bone loss during perimenopause reached half-maximal values of the total bone loss measured around menopause, despite adequate serum estradiol levels.
authors.affiliation: Frauenklinik und Poliklinik, Technische Universität München, Klinikum rechts der Isar, Ismaninger Str. 22, 81675 München, Germany. vanadin.seifert-kaluss@lrz.tum.de
authors.forename: V
authors.initials: V
authors.lastname: Seifert-Klauss
authors.forename: T
authors.initials: T
authors.lastname: Link
authors.forename: C
authors.initials: C
authors.lastname: Heumann
authors.forename: P
authors.initials: P
authors.lastname: Luppa
authors.forename: M
authors.initials: M
authors.lastname: Haseitl
authors.forename: J
authors.initials: J
authors.lastname: Laakmann
authors.forename: J
authors.initials: J
authors.lastname: Rattenhuber
authors.forename: M
authors.initials: M
authors.lastname: Kiechle
mesh_terms: D015519:Bone Density / Q000502:physiology; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008159:Lumbar Vertebrae / Q000378:metabolism; D008875:Middle Aged; D015663:Osteoporosis, Postmenopausal / Q000378:metabolism*; D047648:Perimenopause / Q000378:metabolism*; D017698:Postmenopause / Q000378:metabolism; D011446:Prospective Studies; D014057:Tomography, X-Ray Computed