title: Assessment of dual-energy X-ray absorptiometry measures of bone health in pediatric chronic kidney disease.
abstract: BACKGROUND
  Dual-energy X-ray absorptiometry (DXA) techniques are limited in childhood chronic kidney disease (CKD) by the confounding effect of short stature and opposing parathyroid hormone effects on trabecular and cortical bone. Peripheral quantitative computed tomography (pQCT) is not subject to these limitations.
  
  
  METHODS
  Lumbar spine (LS) and whole-body (WB) DXA and tibia pQCT scans were obtained in 88 stage 4-5 CKD and >650 healthy participants, ages 5-21 years. Sex- and race-specific Z-scores were generated for bone mineral density (BMD) and bone mineral content (BMC) by DXA, relative to age and adjusted for height Z-score (LS-BMD-Z and WB-BMC-Z), and compared to pQCT Z-scores for trabecular BMD (TrabBMD-Z) for age and cortical BMC (CortBMC-Z) for age and tibia length.
  
  
  RESULTS
  LS-BMD-Z [0.50 (95% C.I. 0.28, 0.73), p<0.0001] and TrabBMD-Z [0.53 (0.27, 0.79), p<0.0001] were greater in CKD, and WB-BMC-Z [-0.36 (-0.53, -0.19), p<0.0001] and CortBMC-Z [-0.48 (-0.70, -0.27), p<0.0001] were lower, compared to reference participants. Z-scores were correlated at trabecular (LS-BMD-Z and TrabBMD-Z: R=0.36) and cortical (WB-BMC-Z and CortBMC-Z: R=0.64) sites in CKD; similar to correlations in reference participants.
  
  
  CONCLUSIONS
  Lumbar spine and whole-body DXA suggested greater trabecular BMD and lower cortical BMC in CKD, consistent with pQCT results; however, correlations were modest. Studies are needed to identify methods that predict fracture in childhood CKD.
authors.affiliation: Department of Pediatrics, Children's Hospital of Philadelphia, 3535 Market Street, Room 1564, Philadelphia, PA 19104, USA. griffinl@email.chop.edu
authors.forename: Lindsay M
authors.initials: LM
authors.lastname: Griffin
authors.forename: Heidi J
authors.initials: HJ
authors.lastname: Kalkwarf
authors.forename: Babette S
authors.initials: BS
authors.lastname: Zemel
authors.forename: Justine
authors.initials: J
authors.lastname: Shults
authors.forename: Rachel J
authors.initials: RJ
authors.lastname: Wetzsteon
authors.forename: C Frederic
authors.initials: CF
authors.lastname: Strife
authors.forename: Mary B
authors.initials: MB
authors.lastname: Leonard
mesh_terms: D015502:Absorptiometry, Photon; D000293:Adolescent; D015519:Bone Density; D001842:Bone and Bones / Q000000981:diagnostic imaging*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging; D008297:Male; D051436:Renal Insufficiency, Chronic / Q000150:complications*; D014057:Tomography, X-Ray Computed; D055815:Young Adult