Anne Tsampalieros

Longitudinal Assessment of Bone Density and Structure in Childhood Survivors of Acute Lymphoblastic Leukemia without Cranial Radiation

PURPOSE Children with acute lymphoblastic leukemia (ALL) are at risk for impaired bone accrual. This peripheral quantitative computed tomography study assessed changes in bone mineral density (BMD) and structure after completion of ALL treatment. METHODS Fifty ALL participants, ages 5-22 yr, were enrolled within 2 yr (median 0.8 yr) after completing ALL therapy. Tibia peripheral quantitative computed tomography scans were performed at enrollment and 12 months later. Age-, sex-, and race-specific Z-scores for trabecular BMD (TrabBMD), cortical BMD (CortBMD), and cortical area (CortArea) were generated based on more than 650 reference participants. Multivariable linear regression models examined determinants of changes in Z-scores. RESULTS At enrollment, mean TrabBMD (-1.03±1.34) and CortBMD (-0.84±1.05) Z-scores were low (both P<0.001) compared with reference participants. TrabBMD and CortBMD Z-scores increased to -0.58±1.41 and -0.51±0.91 over 1 yr, respectively (both P<0.001). Changes in cortical outcomes varied according to the interval since completion of therapy. Among those enrolled less than 6 months after therapy, CortArea Z-scores increased and CortBMD Z-scores decreased (both P<0.01). Among those enrolled 6 months or more after therapy, CortArea Z-scores did not change and CortBMD Z-scores increased (P<0.01). Changes in CortArea and CortBMD Z-scores were inversely associated (r=-0.32, P<0.001). Cumulative glucocorticoid exposure, leukemia risk status, and antimetabolite chemotherapy were not associated with outcomes. CONCLUSION TrabBMD was low after completion of ALL therapy and improved significantly. Early increases in cortical dimensions were associated with declines in CortBMD; however, participants further from ALL therapy demonstrated stable cortical dimensions and increases in CortBMD, potentially reflecting the time necessary to mineralize newly formed bone.

Mineral metabolism and cortical volumetric bone mineral density in childhood chronic kidney disease.

CONTEXT The relationships among cortical volumetric bone mineral density (CortBMD) and comprehensive measures of mineral metabolism have not been addressed in chronic kidney disease (CKD). OBJECTIVE The aim of the study was to identify the determinants of CortBMD in childhood CKD. A secondary objective was to assess whether CortBMD was associated with subsequent fracture. DESIGN AND PARTICIPANTS This prospective cohort study included 171 children, adolescents, and young adults (aged 5-21 years) with CKD stages 2-5D at enrollment and 89 1 year later. OUTCOMES Serum measures included vitamin D [25-hydroxyvitamin D (25[OH]D), 1,25-dihydroxyvitamin D (1,25(OH)₂D), 24,25-dihydroxyvitamin D], vitamin D-binding protein, intact PTH, fibroblast growth factor 23, calcium, and phosphorus. Tibia quantitative computed tomography measures of CortBMD were expressed as sex-, race-, and age-specific Z-scores based on 675 controls. Multivariable linear regression identified the independent correlates of CortBMD Z-scores and the change in CortBMD Z-scores. RESULTS Lower calcium (β = .31/1 mg/dL, P = .01) and 25(OH)D (β = .18/10 ng/mL, P = .04) and higher PTH (β = -.02/10%, P = .002) and 1,25(OH)₂D (β = -.07/10%, P < .001) were independently associated with lower CortBMD Z-scores at baseline. The correlations of total, free, and bioavailable 25(OH)D with CortBMD did not differ. Higher baseline 1,25(OH)₂D (P < .05) and greater increases in PTH (P < .001) were associated with greater declines in CortBMD Z-scores. Greater increases in calcium concentrations were associated with greater increases in CortBMD Z-scores in growing children (interaction P = .009). The hazard ratio for fracture was 1.75 (95% confidence interval 1.15-2.67; P = .009) per SD lower baseline CortBMD. CONCLUSIONS Greater PTH and 1,25(OH)₂D and lower calcium concentrations were independently associated with baseline and progressive cortical deficits in childhood CKD. Lower CortBMD Z-score was associated with increased fracture risk.

Long-term inflammation and glucocorticoid therapy impair skeletal modeling during growth in childhood Crohn disease.

CONTEXT Glucocorticoids and inflammation inhibit bone formation; however, the impact on skeletal modeling is unknown. OBJECTIVES The objectives of the study were to examine changes in bone mineral density (BMD) and cortical structure after Crohn disease (CD) diagnosis and identify associations with growth, glucocorticoids, and disease activity. DESIGN/PARTICIPANTS This was a prospective cohort study among 76 CD participants, aged 5-21 years. Tibia quantitative computed tomography trabecular BMD and cortical dimensions were obtained at diagnosis and 6 and 12 and a median of 42 months later; 51 completed the final visit. OUTCOMES Sex, race, and age-specific Z-scores were generated for outcomes based on more than 650 reference participants, and cortical dimension Z-scores were further adjusted for tibia length. Generalized estimating equations were used to model changes in Z-scores. RESULTS Disease activity improved over the study interval (P < .001). Trabecular BMD Z-scores improved over the first 6 months; increases were associated with improved disease activity (P < .001), younger age (P = .005), and increases in vitamin D levels (P = .02). Greater increases in tibia length were associated with greater increases in cortical area Z-scores (P < .001). Greater glucocorticoid doses and disease activity were significantly associated with failure to accrue cortical area and were more pronounced with greater linear growth (interaction P < .05). Mean (±SD) trabecular BMD (-1.0 ± 1.21) and cortical area (-0.57 ± 1.10) Z-scores at the final visit were significantly reduced. CONCLUSIONS CD was associated with persistent deficits in trabecular BMD, although younger participants demonstrated a greater potential for recovery. In addition, greater linear growth was associated with a greater recovery of cortical dimensions, especially among participants with less glucocorticoid exposure and inflammation. These data suggest that younger age and concurrent growth provide a window of opportunity for skeletal recovery.

Glucocorticoid effects on changes in bone mineral density and cortical structure in childhood nephrotic syndrome.

The impact of glucocorticoids (GC) on skeletal development has not been established. The objective of this study was to examine changes in volumetric bone mineral density (vBMD) and cortical structure over 1 year in childhood nephrotic syndrome (NS) and to identify associations with concurrent GC exposure and growth. Fifty‐six NS participants, aged 5 to 21 years, were enrolled a median of 4.3 (0.5 to 8.1) years after diagnosis. Tibia peripheral quantitative computed tomography (pQCT) scans were obtained at enrollment and 6 and 12 months later. Sex, race, and age‐specific Z‐scores were generated for trabecular vBMD (TrabBMD‐Z), cortical vBMD (CortBMD‐Z), and cortical area (CortArea‐Z) based on >650 reference participants. CortArea‐Z was further adjusted for tibia length‐for‐age Z‐score. Quasi‐least squares regression was used to identify determinants of changes in pQCT Z‐scores. At enrollment, mean TrabBMD‐Z (−0.54 ± 1.32) was significantly lower (p = 0.0001) and CortBMD‐Z (0.73 ± 1.16, p < 0.0001) and CortArea‐Z (0.27 ± 0.91, p = 0.03) significantly greater in NS versus reference participants, as previously described. Forty‐eight (86%) participants were treated with GC over the study interval (median dose 0.29 mg/kg/day). On average, TrabBMD‐Z and CortBMD‐Z did not change significantly over the study interval; however, CortArea‐Z decreased (p = 0.003). Greater GC dose (p < 0.001), lesser increases in tibia length (p < 0.001), and lesser increases in CortArea‐Z (p = 0.003) were independently associated with greater increases in CortBMD‐Z. Greater increases in tibia length were associated with greater declines in CortArea‐Z (p < 0.01); this association was absent in reference participants (interaction p < 0.02). In conclusion, GC therapy was associated with increases in CortBMD‐Z, potentially related to suppressed bone formation and greater secondary mineralization. Conversely, greater growth and expansion of CortArea‐Z (ie, new bone formation) were associated with declines in CortBMD‐Z. Greater linear growth was associated with impaired expansion of cortical area in NS. Studies are needed to determine the fracture implications of these findings.

Changes in bone structure and the muscle–bone unit in children with chronic kidney disease

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 age 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 to 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 younger patients (significant interaction terms for trabecular BMD and cortical BMD). The estimated GFR 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.

Use of C-reactive protein in children with newly diagnosed inflammatory bowel disease.

C-reactive protein (CRP), a marker for inflammation, was evaluated with other routine blood tests in children with newly diagnosed inflammatory bowel disease. Evaluation of CRP level helped identify additional patients found to have inflammatory bowel disease at endoscopy, although a sizeable number of patients with mild ulcerative colitis had a normal CRP level.

Evaluation and Management of Proteinuria After Kidney Transplantation.

Abstract Proteinuria occurs commonly after kidney transplantation. Because there are no specific guidelines for defining and detecting proteinuria in transplant recipients, its prevalence can vary depending on the methods used. Most often, the same cutoffs for defining proteinuria in the nontransplant population are applied. There are several risk factors for proteinuria, including some transplant-specific diagnoses and immunosuppressive medications. Posttransplantation proteinuria is associated with reduced graft survival as well as an increased risk of cardiovascular events and death. Treatments to decrease proteinuria have been based on blocking the renin-angiotensin-aldosterone system with the use of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers. This review describes the measurement, prevalence, etiology, prognostic significance, and management of proteinuria in both adult and pediatric transplant recipients.

Changes in DXA and Quantitative CT Measures of Musculoskeletal Outcomes Following Pediatric Renal Transplantation

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.

Dietary fructose intolerance in children and adolescents

Children’s diets contain increased amounts of sweeteners such as fructose. Fructose is present in fruit, honey and some vegetables, and fructose corn syrup is increasingly being consumed as a sweetener in various products including soda-pop.1 Unabsorbed fructose may be fermented in the colon and creates an osmotic load, drawing fluid into the gut lumen and is the basis for recommendations that toddlers with chronic non-specific diarrhoea reduce their intake of apple juice. The abdominal pain, bloating and alteration of bowel habits associated with dietary fructose intolerance are under-recognised in adult patients diagnosed with irritable bowel syndrome.2 3 However, the production of …

Corticosteroid Use and Growth After Pediatric Solid Organ Transplantation: A Systematic Review and Meta-Analysis.

Background A number of corticosteroid minimization and avoidance protocols for post–solid organ transplant have been developed. The study objective was to examine the effect of corticosteroid withdrawal/avoidance on growth and safety parameters in pediatric solid organ transplant recipients. Methods A systematic review using Medline and Embase was performed. All randomized controlled trials (RCT) and observational studies comparing corticosteroid withdrawal/avoidance to controls receiving corticosteroids in pediatric transplant recipients which reported growth as change in height or final height were included. Two reviewers independently abstracted study data and assessed quality. Results The search yielded 930 records, 14 separate studies involving 1146 patients. Renal RCTs (n = 5) showed that corticosteroid withdrawal/avoidance was associated with a significant increase in growth (mean difference in height standard deviation score [SDS], 0.18; 95% confidence interval [95% CI], 0.07-0.29; P = 0.001) compared with those remaining on steroids. In liver RCTs (n = 2), mean difference in height SDS was −0.20 (95% CI, −1.08 to 0.68; P = 0.66). Results for renal observational studies (n = 5) was 0.34 (95% CI, 0.03-0.65; P = 0.03). The most pronounced effect was seen in prepubertal children with SDS of 0.28 (95% CI, 0.14-0.41; P < 0.0001). In pubertal participants this was not observed (SDS, 0.06; 95% CI, −0.04 to 0.15; P = 0.24). Corticosteroid withdrawal/avoidance was not associated with acute rejection (odds ratio [OR], 0.87; P = 0.63), graft failure (OR, 0.45; P = 0.08), or death (OR, 0.34; P = 0.16) in renal trials. Conclusions Corticosteroid withdrawal/avoidance in pediatric renal transplantation is associated with a significant improvement in height. Prepubertal patients appeared to have the greatest benefit. Importantly, the improvement in growth was not accompanied by increased rejection or worsening patient/allograft survival in the short term.