title: Premenopausal women with idiopathic low-trauma fractures and/or low bone mineral density.
abstract: BACKGROUND
  In men, idiopathic osteoporosis (IOP) is often associated with low serum insulin-like growth factor (IGF-1) and reduced bone formation. The characteristics of premenopausal women with IOP are not well defined. We aimed to define the clinical, reproductive, and biochemical characteristics of premenopausal women with unexplained osteoporosis.
  
  
  METHODS
  This is a cross-sectional study of 64 women with unexplained osteoporosis, 45 with fragility fractures, 19 with low bone mineral density (BMD; Z-score less than or equal to -2.0) and 40 normal controls. The following are the main outcome measures: clinical and anthropometric characteristics, reproductive history, BMD, gonadal and calciotropic hormones, IGF-1, and bone turnover markers (BTMs).
  
  
  RESULTS
  Subjects had lower BMI and BMD than controls, but serum and urinary calcium, serum estradiol, vitamin D metabolites, IGF-1, and most BTMs were similar. Serum parathyroid hormone (PTH) and the resorption marker, tartrate-resistant acid phosphatase (TRAP5b), were significantly higher in both groups of subjects than controls and directly associated in all groups. Serum IGF-1 and all BTMs were directly associated in controls, but the association was not significant after controlling for age. There was no relationship between serum IGF-1 and BTMs in subjects. There were few differences between women with fractures and low BMD.
  
  
  CONCLUSIONS
  Higher serum TRAP5b and PTH suggest that increased bone turnover, possibly related to subclinical secondary hyperparathyroidism could contribute to the pathogenesis of IOP. The absence of differences between women with fractures and those with very low BMD indicates that this distinction may not be clinically useful to categorize young women with osteoporosis.
authors.affiliation: Columbia University, New York, NY, USA. ac1044@columbia.edu
authors.forename: A
authors.initials: A
authors.lastname: Cohen
authors.forename: R R
authors.initials: RR
authors.lastname: Recker
authors.forename: J
authors.initials: J
authors.lastname: Lappe
authors.forename: D W
authors.initials: DW
authors.lastname: Dempster
authors.forename: S
authors.initials: S
authors.lastname: Cremers
authors.forename: D J
authors.initials: DJ
authors.lastname: McMahon
authors.forename: E M
authors.initials: EM
authors.lastname: Stein
authors.forename: J
authors.initials: J
authors.lastname: Fleischer
authors.forename: C J
authors.initials: CJ
authors.lastname: Rosen
authors.forename: H
authors.initials: H
authors.lastname: Rogers
authors.forename: R B
authors.initials: RB
authors.lastname: Staron
authors.forename: J
authors.initials: J
authors.lastname: Lemaster
authors.forename: E
authors.initials: E
authors.lastname: Shane
mesh_terms: D015502:Absorptiometry, Photon / Q000379:methods; D000135:Acid Phosphatase / Q000097:blood; D000293:Adolescent; D000328:Adult; D000886:Anthropometry / Q000379:methods; D015415:Biomarkers / Q000097:blood; D015992:Body Mass Index; D015519:Bone Density / Q000502:physiology; D016723:Bone Remodeling / Q000502:physiology; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D004032:Diet; D005260:Female; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D007527:Isoenzymes / Q000097:blood; D008875:Middle Aged; D010024:Osteoporosis / Q000097:blood / Q000503:physiopathology*; D058866:Osteoporotic Fractures / Q000097:blood / Q000503:physiopathology*; D010281:Parathyroid Hormone / Q000097:blood; D017697:Premenopause / Q000097:blood / Q000502:physiology*; D017584:Reproductive History; D000071681:Tartrate-Resistant Acid Phosphatase; D055815:Young Adult
chemical_list: D015415:Biomarkers; D007527:Isoenzymes; D010281:Parathyroid Hormone; D007334:Insulin-Like Growth Factor I; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase