title: Changes in DXA and quantitative CT measures of musculoskeletal outcomes following pediatric renal transplantation.
abstract: This prospective study evaluated changes in dual energy X-ray absorptiometry (DXA) whole body bone mineral content (WB-BMC) and spine areal bone mineral density (spine-BMD), and tibia quantitative computed tomography (QCT) trabecular and cortical volumetric BMD and cortical area in 56 children over 12 months following renal transplantation. At transplant, spine-BMD Z-scores were greater in younger recipients (<13 years), versus 898 reference participants (p < 0.001). In multivariate models, greater decreases in spine-BMD Z-scores were associated with greater glucocorticoid dose (p < 0.001) and declines in parathyroid hormone levels (p = 0.008). Changes in DXA spine-BMD and QCT trabecular BMD were correlated (r = 0.47, p < 0.01). At 12 months, spine-BMD Z-scores remained elevated in younger recipients, but did not differ in older recipients (≥ 13) and reference participants. Baseline WB-BMC Z-scores were significantly lower than reference participants (p = 0.02). Greater glucocorticoid doses were associated with declines in WB-BMC Z-scores (p < 0.001) while greater linear growth was associated with gains in WB-BMC Z-scores (p = 0.01). Changes in WB-BMC Z-scores were associated with changes in tibia cortical area Z-scores (r = 0.52, p < 0.001), but not changes in cortical BMD Z-scores. Despite resolution of muscle deficits, WB-BMC Z-scores at 12 months remained significantly reduced. These data suggest that spine and WB DXA provides insight into trabecular and cortical outcomes following pediatric renal transplantation.
authors.affiliation: Department of Pediatrics, Children's Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA.
authors.forename: A
authors.initials: A
authors.lastname: Tsampalieros
authors.forename: L
authors.initials: L
authors.lastname: Griffin
authors.forename: A M
authors.initials: AM
authors.lastname: Terpstra
authors.forename: H J
authors.initials: HJ
authors.lastname: Kalkwarf
authors.forename: J
authors.initials: J
authors.lastname: Shults
authors.forename: B J
authors.initials: BJ
authors.lastname: Foster
authors.forename: B S
authors.initials: BS
authors.lastname: Zemel
authors.forename: D L
authors.initials: DL
authors.lastname: Foerster
authors.forename: M B
authors.initials: MB
authors.lastname: Leonard
mesh_terms: D015502:Absorptiometry, Photon; D000293:Adolescent; D001823:Body Composition; D015519:Bone Density / Q000502:physiology*; D002648:Child; D005260:Female; D006801:Humans; D016030:Kidney Transplantation; D008297:Male; D010281:Parathyroid Hormone / Q000378:metabolism; D011446:Prospective Studies; D013131:Spine / Q000378:metabolism; D013977:Tibia / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed; D055815:Young Adult
chemical_list: D010281:Parathyroid Hormone
keywords: Bone mineral density; nutrition; pediatric; renal transplantation