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Lee DY, Wetzsteon RJ, Zemel BS, Shults J, Organ JM, Foster BJ, Herskovitz RM, Foerster DL, Leonard MB. Muscle torque relative to cross-sectional area and the functional muscle-bone unit in children and adolescents with chronic disease. J Bone Miner Res 2015; 30:575-83. [PMID: 25264231 PMCID: PMC4532328 DOI: 10.1002/jbmr.2375] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Revised: 09/22/2014] [Accepted: 09/23/2014] [Indexed: 12/14/2022]
Abstract
Measures of muscle mass or size are often used as surrogates of forces acting on bone. However, chronic diseases may be associated with abnormal muscle force relative to muscle size. The muscle-bone unit was examined in 64 children and adolescents with new-onset Crohn's disease (CD), 54 with chronic kidney disease (CKD), 51 treated with glucocorticoids for nephrotic syndrome (NS), and 264 healthy controls. Muscle torque was assessed by isometric ankle dynamometry. Calf muscle cross-sectional area (CSA) and tibia cortical section modulus (Zp) were assessed by quantitative CT. Log-linear regression was used to determine the relations among muscle CSA, muscle torque, and Zp, adjusted for tibia length, age, Tanner stage, sex, and race. Muscle CSA and muscle torque-relative-to-muscle CSA were significantly lower than controls in advanced CKD (CSA -8.7%, p = 0.01; torque -22.9%, p < 0.001) and moderate-to-severe CD (CSA -14.1%, p < 0.001; torque -7.6%, p = 0.05), but not in NS. Zp was 11.5% lower in advanced CKD (p = 0.005) compared to controls, and this deficit was attenuated to 6.7% (p = 0.05) with adjustment for muscle CSA. With additional adjustment for muscle torque and body weight, Zp was 5.9% lower and the difference with controls was no longer significant (p = 0.09). In participants with moderate-to-severe CD, Zp was 6.8% greater than predicted (p = 0.01) given muscle CSA and torque deficits (R(2) = 0.92), likely due to acute muscle loss in newly-diagnosed patients. Zp did not differ in NS, compared with controls. In conclusion, muscle torque relative to muscle CSA was significantly lower in CKD and CD, compared with controls, and was independently associated with Zp. Future studies are needed to determine if abnormal muscle strength contributes to progressive bone deficits in chronic disease, independent of muscle area. © 2014 American Society for Bone and Mineral Research.
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Affiliation(s)
- Dale Y Lee
- Department of Pediatrics, Children's Hospital of Philadelphia (CHOP), Philadelphia, PA, USA
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Tsampalieros A, Griffin L, Terpstra AM, Kalkwarf HJ, Shults J, Foster BJ, Zemel BS, Foerster DL, Leonard MB. Changes in DXA and quantitative CT measures of musculoskeletal outcomes following pediatric renal transplantation. Am J Transplant 2014; 14:124-32. [PMID: 24298998 PMCID: PMC3951446 DOI: 10.1111/ajt.12524] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Revised: 08/30/2013] [Accepted: 09/27/2013] [Indexed: 01/25/2023]
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.
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Affiliation(s)
- Anne Tsampalieros
- Department of Pediatrics, Children's Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania
| | - Lindsay Griffin
- Department of Pediatrics, Children's Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania
| | - Anniek M Terpstra
- Department of Pediatrics, Children's Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania
| | - Heidi J Kalkwarf
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center
| | - Justine Shults
- Department of Pediatrics, Children's Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania
| | - Bethany J Foster
- Department of Pediatrics, Children's Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania
| | - Babette S Zemel
- Department of Pediatrics, Children's Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania
| | - Debbie L Foerster
- Department of Pediatrics, Children's Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania
| | - Mary B. Leonard
- Department of Pediatrics, Children's Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania, Department of Biostatistics and Epidemiology, Perelman School of Medicine at the University of Pennsylvania
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Tsampalieros A, Kalkwarf HJ, Wetzsteon RJ, Shults J, Zemel BS, Foster BJ, Foerster DL, Leonard MB. Changes in bone structure and the muscle-bone unit in children with chronic kidney disease. Kidney Int 2013; 83:495-502. [PMID: 23032560 PMCID: PMC4040969 DOI: 10.1038/ki.2012.347] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The impact of pediatric chronic kidney disease (CKD) on acquisition of volumetric bone mineral density (BMD) and cortical dimensions is lacking. To address this issue, we obtained tibia quantitative computed tomography scans from 103 patients aged 5-21 years with CKD (26 on dialysis) at baseline and 12 months later. Gender, ethnicity, tibia length, and/or age-specific Z-scores were generated for trabecular and cortical BMD, cortical area, periosteal and endosteal circumference, and muscle area based on over 700 reference subjects. Muscle area, cortical area, and periosteal and endosteal Z-scores were significantly lower at baseline compared with the reference cohort. Cortical BMD, cortical area, and periosteal Z-scores all exhibited a significant further decrease over 12 months. Higher parathyroid hormone levels were associated with significantly greater increases in trabecular BMD and decreases in cortical BMD in the younger patients (significant interaction terms for trabecular BMD and cortical BMD). The estimated glomerular filtration rate was not associated with changes in BMD Z-scores independent of parathyroid hormone. Changes in muscle and cortical area were significantly and positively associated in control subjects but not in CKD patients. Thus, children and adolescents with CKD have progressive cortical bone deficits related to secondary hyperparathyroidism and potential impairment of the functional muscle-bone unit. Interventions are needed to enhance bone accrual in childhood-onset CKD.
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Affiliation(s)
- Anne Tsampalieros
- Department of Pediatrics, Children's Hospital of Eastern Ontario, University of Ottawa, Ottawa, ON
- Department of Pediatrics, Children's Hospital of Philadelphia, Perlman School of Medicine at the University of Pennsylvania
| | - Heidi J Kalkwarf
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center
| | - Rachel J Wetzsteon
- Department of Pediatrics, Children's Hospital of Philadelphia, Perlman School of Medicine at the University of Pennsylvania
| | - Justine Shults
- Department of Pediatrics, Children's Hospital of Philadelphia, Perlman School of Medicine at the University of Pennsylvania
- Department of Biostatistics and Epidemiology, Perlman School of Medicine at the University of Pennsylvania
| | - Babette S Zemel
- Department of Pediatrics, Children's Hospital of Philadelphia, Perlman School of Medicine at the University of Pennsylvania
| | - Bethany J. Foster
- Department of Pediatrics, Montreal Children's Hospital, Montreal, Quebec, Canada
- Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, Quebec, Canada
| | - Debbie L Foerster
- Department of Pediatrics, Children's Hospital of Philadelphia, Perlman School of Medicine at the University of Pennsylvania
| | - Mary B. Leonard
- Department of Pediatrics, Children's Hospital of Philadelphia, Perlman School of Medicine at the University of Pennsylvania
- Department of Biostatistics and Epidemiology, Perlman School of Medicine at the University of Pennsylvania
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Terpstra AM, Kalkwarf HJ, Shults J, Zemel BS, Wetzsteon RJ, Foster BJ, Strife CF, Foerster DL, Leonard MB. Bone density and cortical structure after pediatric renal transplantation. J Am Soc Nephrol 2012; 23:715-26. [PMID: 22282589 PMCID: PMC3312505 DOI: 10.1681/asn.2011050480] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Accepted: 10/30/2011] [Indexed: 01/24/2023] Open
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.
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MESH Headings
- Adolescent
- Age Factors
- Anthropometry
- Bone Demineralization, Pathologic/diagnostic imaging
- Bone Demineralization, Pathologic/etiology
- Bone Demineralization, Pathologic/physiopathology
- Bone Density/physiology
- Case-Control Studies
- Chi-Square Distribution
- Child
- Child, Preschool
- Cohort Studies
- Female
- Follow-Up Studies
- Hospitals, Pediatric
- Humans
- Imaging, Three-Dimensional
- Kidney Failure, Chronic/etiology
- Kidney Failure, Chronic/physiopathology
- Kidney Failure, Chronic/surgery
- Kidney Transplantation/adverse effects
- Kidney Transplantation/methods
- Male
- Multivariate Analysis
- Parathyroid Hormone/blood
- Reference Values
- Risk Assessment
- Sex Factors
- Statistics, Nonparametric
- Tibia/diagnostic imaging
- Tibia/pathology
- Tomography, X-Ray Computed/methods
- Young Adult
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Affiliation(s)
- Anniek M. Terpstra
- Department of Epidemiology, Biostatistics and Health Technology Assessment, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
- Department of Pediatrics, Children’s Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Heidi J. Kalkwarf
- Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio
| | - Justine Shults
- Department of Pediatrics, Children’s Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
- Department of Biostatistics and Epidemiology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania; and
| | - Babette S. Zemel
- Department of Pediatrics, Children’s Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Rachel J. Wetzsteon
- Department of Pediatrics, Children’s Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Bethany J. Foster
- Department of Pediatrics, Montreal Children's Hospital, Montreal, Quebec, Canada
| | - C. Frederic Strife
- Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio
| | - Debbie L. Foerster
- Department of Pediatrics, Children’s Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Mary B. Leonard
- Department of Pediatrics, Children’s Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
- Department of Biostatistics and Epidemiology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania; and
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Wetzsteon RJ, Kalkwarf HJ, Shults J, Zemel BS, Foster BJ, Griffin L, Strife CF, Foerster DL, Jean-Pierre DK, Leonard MB. Volumetric bone mineral density and bone structure in childhood chronic kidney disease. J Bone Miner Res 2011; 26:2235-44. [PMID: 21590737 PMCID: PMC3304436 DOI: 10.1002/jbmr.427] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Chronic kidney disease (CKD) is associated with increased fracture risk and skeletal deformities. The impact of CKD on volumetric bone mineral density (vBMD) and cortical dimensions during growth is unknown. Tibia quantitative computed tomographic scans were obtained in 156 children with CKD [69 stages 2 to 3, 51 stages 4 to 5, and 36 stage 5D (dialysis)] and 831 healthy participants aged 5 to 21 years. Sex-, race-, and age- or tibia length-specific Z-scores were generated for trabecular BMD (TrabBMD), cortical BMD (CortBMD), cortical area (CortArea) and endosteal circumference (EndoC). Greater CKD severity was associated with a higher TrabBMD Z-score in younger participants (p < .001) compared with healthy children; this association was attenuated in older participants (interaction p < .001). Mean CortArea Z-score was lower (p < .01) in CKD 4-5 [-0.49, 95% confidence interval (CI) -0.80, -0.18)] and CKD 5D (-0.49, 95% CI -0.83, -0.15) compared with healthy children. Among CKD participants, parathyroid hormone (PTH) levels were positively associated with TrabBMD Z-score (p < .01), and this association was significantly attenuated in older participants (interaction p < .05). Higher levels of PTH and biomarkers of bone formation (bone-specific alkaline phosphatase) and resorption (serum C-terminal telopeptide of type 1 collagen) were associated with lower CortBMD and CortArea Z-scores and greater EndoC Z-score (r = 0.18-0.36, all p ≤ .02). CortBMD Z-score was significantly lower in CKD participants with PTH levels above versus below the upper limit of the Kidney Disease Outcome Quality Initiative (KDOQI) CKD stage-specific target range: -0.46 ± 1.29 versus 0.12 ± 1.14 (p < .01). In summary, childhood CKD and secondary hyperparathyroidism were associated with significant reductions in cortical area and CortBMD and greater TrabBMD in younger children. Future studies are needed to establish the fracture implications of these alterations and to determine if cortical and trabecular abnormalities are reversible.
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Affiliation(s)
| | - Heidi J. Kalkwarf
- Department of Pediatrics, Cincinnati Children’s Hospital Medical Center
| | - Justine Shults
- Department of Biostatistics and Epidemiology, University of Pennsylvania School of Medicine
| | | | | | - Lindsay Griffin
- Department of Pediatrics, Children’s Hospital of Philadelphia
| | | | | | | | - Mary B. Leonard
- Department of Pediatrics, Children’s Hospital of Philadelphia
- Department of Biostatistics and Epidemiology, University of Pennsylvania School of Medicine
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Foster BJ, Kalkwarf HJ, Shults J, Zemel BS, Wetzsteon RJ, Thayu M, Foerster DL, Leonard MB. Association of chronic kidney disease with muscle deficits in children. J Am Soc Nephrol 2011; 22:377-86. [PMID: 21115614 PMCID: PMC3029910 DOI: 10.1681/asn.2010060603] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2010] [Accepted: 09/22/2010] [Indexed: 01/08/2023] Open
Abstract
The effect of chronic kidney disease (CKD) on muscle mass in children, independent of poor growth and delayed maturation, is not well understood. We sought to characterize whole body and regional lean mass (LM) and fat mass (FM) in children and adolescents with CKD and to identify correlates of LM deficits in CKD. We estimated LM and FM from dual energy x-ray absorptiometry scans in 143 children with CKD and 958 controls at two pediatric centers. We expressed whole body, trunk, and leg values of LM and FM as Z-scores relative to height, sitting height, and leg length, respectively, using the controls as the reference. We used multivariable regression models to compare Z-scores in CKD and controls, adjusted for age and maturation, and to identify correlates of LM Z-scores in CKD. Greater CKD severity associated with greater leg LM deficits. Compared with controls, leg LM Z-scores were similar in CKD stages 2 to 3 (difference: 0.02 [95% CI: -0.20, 0.24]; P = 0.8), but were lower in CKD stages 4 to 5 (-0.41 [-0.66, -0.15]; P = 0.002) and dialysis (-1.03 [-1.33, -0.74]; P < 0.0001). Among CKD participants, growth hormone therapy associated with greater leg LM Z-score (0.58 [0.03, 1.13]; P = 0.04), adjusted for CKD severity. Serum albumin, bicarbonate, and markers of inflammation did not associate with LM Z-scores. CKD associated with greater trunk LM and FM, variable whole body LM, and normal leg FM, compared with controls. In conclusion, advanced CKD associates with significant deficits in leg lean mass, indicating skeletal muscle wasting. These data call for prospective studies of interventions to improve muscle mass among children with CKD.
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Affiliation(s)
- Bethany J Foster
- Montreal Children's Hospital, 2300 Tupper Street, Montreal, Quebec, H3H 1P3 Canada.
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