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ABSTRACT: 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.
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.
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.
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.
Pediatric Nephrology 02/2012; 27(7):1139-48. · 2.52 Impact Factor
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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.
Journal of the American Society of Nephrology 01/2012; 23(4):715-26. · 9.66 Impact Factor
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ABSTRACT: Here we determined if vitamin D deficiency is more common in children with chronic kidney disease compared to healthy children. In addition, we sought to identify disease-specific risk factors for this deficiency, as well as its metabolic consequences. We found that nearly half of 182 patients (ages 5 to 21) with kidney disease (stages 2 to 5) and a third of age-matched 276 healthy children were 25-hydroxyvitamin D deficient (<20 ng/ml). The risk of deficiency was significantly greater in advanced disease. Focal segmental glomerulosclerosis and low albumin were significantly associated with lower 25-hydroxyvitamin D, which, in turn, was associated with significantly higher intact parathyroid hormone levels. We found that 25-hydroxyvitamin D levels were positively associated with 1,25-dihydroxyvitamin D, the relationship being greatest in advanced disease (significant interaction), and inversely related to those of inflammatory markers C-reactive protein and IL-6. The association with C-reactive protein persisted when adjusted for the severity of kidney disease. Thus, lower 25-hydroxyvitamin D may contribute to hyperparathyroidism, inflammation, and lower 1,25-dihydroxyvitamin D in children and adolescents, especially those with advanced kidney disease.
Kidney International 12/2011; 81(7):690-7. · 6.61 Impact Factor
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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.
Journal of bone and mineral research: the official journal of the American Society for Bone and Mineral Research 05/2011; 26(9):2235-44. · 6.04 Impact Factor
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ABSTRACT: The objectives were to determine the prevalence of vitamin D deficiency [25(OH)D < 10 ng/ml] in pediatric renal transplant (RTx) recipients, compared with controls and identify correlates of changes in 25(OH)D and intact parathyroid hormone (iPTH) levels following transplantation. Serum 25(OH)D, 1,25(OH)(2)D, and iPTH were measured once in 275 healthy controls and at transplantation, and 3 and 12 months posttransplantation in 58 RTx recipients. Multivariate logistic regression models determined the odds ratio (OR) of vitamin D deficiency in RTx recipients vs. controls adjusted for age, sex, race, and season. Generalized estimating equations were used to assess changes following transplantation. At transplantation, 22% of nonblack and 27% of black RTx recipients were vitamin D deficient. The adjusted OR of vitamin D deficiency was greater in RTx recipients (p < 0.001) compared with controls; however, the transplant association was greater in nonblack vs. black individuals (interaction p = 0.02). Overall, 25(OH)D levels did not change significantly following transplantation. Younger age (p < 0.01), nonblack race (p < 0.001), visits in nonwinter months (p < 0.001), and supplementation with ≥400 IU/day ergo/cholecalciferol (p < 0.001) were associated with increases (or lesser declines) in 25(OH)D following transplantation. Increases in 25(OH)D levels (p < 0.001) and vitamin D supplementation (p < 0.01) were associated with greater reductions in iPTH levels following transplantation, independent of 1,25(OH)(2)D levels.
Pediatric Nephrology 12/2010; 25(12):2509-16. · 2.52 Impact Factor
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Marc B Lande,
Christina Gullion,
Ronald J Hogg,
Bernard Gauthier,
Binod Shah,
Mary B Leonard,
Melvin Bonilla-Felix,
Martin Nash,
Shane Roy, C Frederic Strife,
Gerald Arbus
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ABSTRACT: A retrospective cohort study was conducted by the Southwest Pediatric Nephrology Study Group (SPNSG) to address whether a longer initial course of corticosteroids in patients with idiopathic nephrotic syndrome (INS) provides superior protection against relapse without increased adverse effects. In order to be included in the evaluation, patients with INS must have responded to an initial steroid course, either standard or long regimen as defined here, and completed at least 1 year of follow-up. The standard regimen consisted of prednisone 2.0+/-0.3 mg/kg per day or 60+/-10 mg/m(2) per day for 28+/-4 days, followed by alternate-day prednisone for 4-12 weeks. The long regimen consisted of daily prednisone 2.0+/-0.3 mg/kg per day or 60+/-10 mg/m(2) per day for 42+/-6 days, followed by alternate-day prednisone for 6-14 weeks. The primary outcome measure was relapse of NS within 12 months of discontinuing the initial course of prednisone. There were 151 children who met the criteria for the study; 82 received the standard regimen and 69 the long regimen. The two groups did not differ in age, race, blood pressure, serum albumin, or serum cholesterol prior to the initial steroid course. The cumulative prednisone dose was 49% higher in the long regimen group than in the standard regimen group. Relapse within 12 months was reported in 72.5% of patients who received the long regimen versus 84.1% of those who received the standard regimen. The odds ratio for relapse within 12 months was 0.496 (95% confidence interval 0.22, 1.088), long versus standard regimen. This did not reach statistical significance ( chi(2)=3.058, P=0.08). The odds ratio of experiencing at least one side effect was 3.76, long relative to standard regimen ( n=133, P<0.001). Our data suggest that prolongation of the steroid treatment for the initial episode of steroid-sensitive NS may have a beneficial effect, but at the cost of increased side effects. However, definitive conclusions are limited by the retrospective design of the study and the number of patients. This may have caused failure to achieve statistical significance on the basis of a type II error.
Pediatric Nephrology 04/2003; 18(4):342-6. · 2.52 Impact Factor
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Marc B. Lande,
Christina Gullion,
Ronald J. Hogg,
Bernard Gauthier,
Binod Shah,
Mary B. Leonard,
Melvin Bonilla-Felix,
Martin Nash,
Shane Roy, C. Frederic Strife,
Gerald Arbus
[show abstract]
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ABSTRACT: A retrospective cohort study was conducted by the Southwest Pediatric Nephrology Study Group (SPNSG) to address whether a longer initial course of corticosteroids in patients with idiopathic nephrotic syndrome (INS) provides superior protection against relapse without increased adverse effects. In order to be included in the evaluation, patients with INS must have responded to an initial steroid course, either standard or long regimen as defined here, and completed at least 1 year of follow-up. The standard regimen consisted of prednisone 2.0ǂ.3 mg/kg per day or 60ᆞ mg/m2 per day for 28dž days, followed by alternate-day prednisone for 4-12 weeks. The long regimen consisted of daily prednisone 2.0ǂ.3 mg/kg per day or 60ᆞ mg/m2 per day for 42Lj days, followed by alternate-day prednisone for 6-14 weeks. The primary outcome measure was relapse of NS within 12 months of discontinuing the initial course of prednisone. There were 151 children who met the criteria for the study; 82 received the standard regimen and 69 the long regimen. The two groups did not differ in age, race, blood pressure, serum albumin, or serum cholesterol prior to the initial steroid course. The cumulative prednisone dose was 49% higher in the long regimen group than in the standard regimen group. Relapse within 12 months was reported in 72.5% of patients who received the long regimen versus 84.1% of those who received the standard regimen. The odds ratio for relapse within 12 months was 0.496 (95% confidence interval 0.22, 1.088), long versus standard regimen. This did not reach statistical significance (В=3.058, P=0.08). The odds ratio of experiencing at least one side effect was 3.76, long relative to standard regimen (n=133, P<0.001). Our data suggest that prolongation of the steroid treatment for the initial episode of steroid-sensitive NS may have a beneficial effect, but at the cost of increased side effects. However, definitive conclusions are limited by the retrospective design of the study and the number of patients. This may have caused failure to achieve statistical significance on the basis of a type II error.
Pediatric Nephrology 03/2003; 18(4):342-346. · 2.52 Impact Factor
