title: Bone density and cortical structure after pediatric renal transplantation.
abstract: The impact of renal transplantation on trabecular and cortical bone mineral density (BMD) and cortical structure is unknown. We obtained quantitative computed tomography scans of the tibia in pediatric renal transplant recipients at transplantation and 3, 6, and 12 months; 58 recipients completed at least two visits. We used more than 700 reference participants to generate Z-scores for trabecular BMD, cortical BMD, section modulus (a summary measure of cortical dimensions and strength), and muscle and fat area. At baseline, compared with reference participants, renal transplant recipients had significantly lower mean section modulus and muscle area; trabecular BMD was significantly greater than reference participants only in transplant recipients younger than 13 years. After transplantation, trabecular BMD decreased significantly in association with greater glucocorticoid exposure. Cortical BMD increased significantly in association with greater glucocorticoid exposure and greater decreases in parathyroid hormone levels. Muscle and fat area both increased significantly, but section modulus did not improve. At 12 months, transplantation associated with significantly lower section modulus and greater fat area compared with reference participants. Muscle area and cortical BMD did not differ significantly between transplant recipients and reference participants. Trabecular BMD was no longer significantly elevated in younger recipients and was low in older recipients. Pediatric renal transplant associated with persistent deficits in section modulus, despite recovery of muscle, and low trabecular BMD in older recipients. Future studies should determine the implications of these data on fracture risk and identify strategies to improve bone density and structure.
authors.affiliation: Department of Epidemiology, Biostatistics and Health Technology Assessment, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
authors.forename: Anniek M
authors.initials: AM
authors.lastname: Terpstra
authors.forename: Heidi J
authors.initials: HJ
authors.lastname: Kalkwarf
authors.forename: Justine
authors.initials: J
authors.lastname: Shults
authors.forename: Babette S
authors.initials: BS
authors.lastname: Zemel
authors.forename: Rachel J
authors.initials: RJ
authors.lastname: Wetzsteon
authors.forename: Bethany J
authors.initials: BJ
authors.lastname: Foster
authors.forename: C Frederic
authors.initials: CF
authors.lastname: Strife
authors.forename: Debbie L
authors.initials: DL
authors.lastname: Foerster
authors.forename: Mary B
authors.initials: MB
authors.lastname: Leonard
mesh_terms: D000293:Adolescent; D000367:Age Factors; D000886:Anthropometry; D018488:Bone Demineralization, Pathologic / Q000000981:diagnostic imaging* / Q000209:etiology / Q000503:physiopathology; D015519:Bone Density / Q000502:physiology*; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006776:Hospitals, Pediatric; D006801:Humans; D021621:Imaging, Three-Dimensional; D007676:Kidney Failure, Chronic / Q000209:etiology / Q000503:physiopathology / Q000601:surgery; D016030:Kidney Transplantation / Q000009:adverse effects* / Q000379:methods; D008297:Male; D015999:Multivariate Analysis; D010281:Parathyroid Hormone / Q000097:blood; D012016:Reference Values; D018570:Risk Assessment; D012737:Sex Factors; D018709:Statistics, Nonparametric; D013977:Tibia / Q000000981:diagnostic imaging* / Q000473:pathology; D014057:Tomography, X-Ray Computed / Q000379:methods; D055815:Young Adult
chemical_list: D010281:Parathyroid Hormone