title: Bone density and skeletal metabolism are altered in idiopathic hypercalciuria.
abstract: OBJECTIVE
  To study bone density in hypercalciuric patients, when classified according to the main metabolic defect.
  
  
  METHODS
  We studied 49 patients, aged 19-60 years with calcium stones and idiopathic hypercalcuria. All subjects underwent an evaluation of mineral metabolism and a spinal and femoral DEXA measurement. Then, patients were classified as having Fasting (FH, 31 subjects) or Absorptive (AH, 18 patients) Hypercalciuria according to a standard oral calcium load.
  
  
  RESULTS
  Spinal bone density was lower only in FH patients as compared to controls (p <0.001). Bone alkaline phosphatase and urine hydroxyproline were higher with respect to controls only in patients with FH (p <0.005 and p <0.015, respectively). After low calcium diet, hydroxyproline excretion continued to be higher in FH patients (p <0.05). Although in the normal range, serum and urine uric acid were higher in hypercalciuric subjects (p <0.03 and p <0.005, respectively); blood pH was lower in hypercalciuric patients than in controls (p <0.01). In FH patients urine hydroxyproline negatively correlated with spinal and femoral density (p <0.001 and p <0.005, respectively), and blood pH positively correlated with spinal density.
  
  
  CONCLUSIONS
  a disordered bone metabolism and bone loss are present only in patients with fasting hypercalciuria. An excessive acid load, possibly of dietary origin, might be involved as a pathogenetic factor.
authors.affiliation: Institute of Internal Medicine and National Research Council-Centre for Aging Studies of Padova, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Giannini
authors.forename: M
authors.initials: M
authors.lastname: Nobile
authors.forename: L
authors.initials: L
authors.lastname: Sartori
authors.forename: L
authors.initials: L
authors.lastname: Calò
authors.forename: A
authors.initials: A
authors.lastname: Tasca
authors.forename: L
authors.initials: L
authors.lastname: Dalle Carbonare
authors.forename: M
authors.initials: M
authors.lastname: Ciuffreda
authors.forename: A
authors.initials: A
authors.lastname: D'Angelo
authors.forename: F
authors.initials: F
authors.lastname: Pagano
authors.forename: G
authors.initials: G
authors.lastname: Crepaldi
mesh_terms: D015502:Absorptiometry, Photon; D000328:Adult; D015519:Bone Density; D001851:Bone Diseases, Metabolic / Q000209:etiology* / Q000378:metabolism; D001842:Bone and Bones / Q000378:metabolism; D002118:Calcium / Q000652:urine*; D002136:Calcium, Dietary / Q000008:administration & dosage; D016022:Case-Control Studies; D005215:Fasting / Q000378:metabolism; D005260:Female; D006801:Humans; D007669:Kidney Calculi / Q000737:chemistry / Q000652:urine*; D008297:Male; D008875:Middle Aged
chemical_list: D002136:Calcium, Dietary; D002118:Calcium