Jon M. Burnham

Longitudinal Assessment of Bone Density and Structure in an Incident Cohort of Children With Crohn's Disease

BACKGROUND & AIMS The impact of childhood Crohns disease (CD) on volumetric bone mineral density (vBMD), bone structure, and muscle mass have not been established. The objective of this longitudinal study was to assess musculoskeletal outcomes in an incident cohort of children with CD using peripheral quantitative computed tomography (pQCT). METHODS Tibia pQCT was performed in 78 CD subjects (ages, 5-18 years) at diagnosis and in 67 over the subsequent year. pQCT outcomes were converted to sex- and race-specific z scores based on reference data in over 650 controls. Multivariable linear regression models identified factors associated with changes in bone outcomes. RESULTS At diagnosis, CD subjects had significant deficits in trabecular vBMD (z score, -1.32+/-1.32; P< .001), cortical section modulus (a measure of bone geometry and strength) (z score, -0.44+/-1.11; P< .01), and muscle (z score, -0.96+/-1.02; P< .001) compared with controls. Over the first 6 months, trabecular vBMD and muscle z scores improved significantly (both, P< .001); however, section modulus worsened (P= .0001), and all 3 parameters remained low after 1 year. Increases in muscle z scores were associated with less severe declines in cortical section modulus z scores. Improvements in trabecular vBMD z scores were greater in prepubertal subjects. Glucocorticoids were associated with increases in cortical vBMD. CONCLUSIONS Substantial deficits in trabecular vBMD, cortical bone geometry, and muscle were observed at CD diagnosis. Trabecular vBMD improved incompletely; however, cortical deficits progressed despite improvements in muscle. Glucocorticoids were not associated with bone loss. Therapies to improve bone accrual in childhood CD are needed.

Whole body BMC in pediatric Crohn disease: Independent effects of altered growth, maturation, and body composition

Whole body BMC was assessed in 104 children and young adults with CD and 233 healthy controls. CD was associated with significant deficits in BMC and lean mass, relative to height. Adjustment for lean mass eliminated the bone deficit in CD. Steroid exposure was associated with short stature but not bone deficits relative to height.

Effects of Corticosteroid on Henoch-Schönlein Purpura: A Systematic Review

OBJECTIVE. No consensus exists among general pediatricians or pediatric rheumatologists regarding whether corticosteroid therapy ameliorates the acute manifestations of Henoch-Schönlein purpura or mitigates renal injury. Therefore, we sought to synthesize the reported experimental and observational data regarding corticosteroid use. METHODS. We performed a meta-analysis based on a comprehensive review of the literature in the Medline database (1956 to January 2007) and the Cochrane Controlled Trials Register. On the basis of reported outcomes among patients with Henoch-Schönlein purpura who were treated at diagnosis with corticosteroids compared with patients treated with supportive care only, we calculated odds ratios for the resolution of abdominal pain, the need for surgical intervention secondary to severe pain or intussusception, the likelihood of Henoch-Schönlein purpura recurrence, and the development of transient or persistent renal disease. RESULTS. Of 201 articles retrieved from the initial literature search, 15 were eligible for inclusion. Corticosteroid treatment did not reduce the median time to resolution of abdominal pain but did significantly reduce the mean resolution time and increased the odds of resolution within 24 hours. Early corticosteroid treatment significantly reduced the odds of developing persistent renal disease. In addition, although the results were not statistically significant, the prospective data suggest reduced odds of both surgical intervention and recurrence. CONCLUSIONS. Corticosteroids, given early in the course of illness, seem to produce consistent benefits for several major clinically relevant Henoch-Schönlein purpura outcomes.

Effects of Sex, Race, and Puberty on Cortical Bone and the Functional Muscle Bone Unit in Children, Adolescents, and Young Adults

CONTEXT Sex and race differences in bone development are associated with differences in growth, maturation, and body composition. OBJECTIVE The aim of the study was to determine the independent effects of sex, race, and puberty on cortical bone development and muscle-bone relations in children and young adults. DESIGN AND PARTICIPANTS We conducted a cross-sectional study of 665 healthy participants (310 male, 306 black) ages 5-35 yr. OUTCOMES Tibia peripheral quantitative computed tomography measures were made of cortical bone mineral content (BMC) and bone mineral density (BMD), periosteal (Peri) and endosteal circumferences, section modulus (Zp), and muscle area. Regression models were adjusted for tibia length, age, race, sex, and Tanner stage. RESULTS All cortical measures were greater in blacks than whites (all P < or = 0.001) in Tanner stages 1-4; however, differences in BMC, Peri, and Zp were negligible in Tanner stage 5 (all interactions, P < 0.01). Cortical BMC, Peri, and Zp were lower in females than males in all Tanner stages (all P < 0.001), and the sex differences in Peri and Zp were greater in Tanner stage 5 (interaction, P < 0.02). Cortical BMD was greater (P < 0.0001) and endosteal circumference was lower (P < 0.01) in Tanner 3-5 females, compared with males. Adjustment for muscle area attenuated but did not eliminate sex and race differences in cortical dimensions. Associations between muscle and bone outcomes did not differ according to sex or race. CONCLUSION Sex and race were associated with maturation-specific differences in cortical BMD and dimensions that were not fully explained by differences in bone length or muscle. No race or sex differences in the functional muscle bone unit were identified.

Body-composition alterations consistent with cachexia in children and young adults with Crohn disease

BACKGROUND Crohn disease (CD) in children is associated with low body mass index (BMI), poor growth, and delayed maturation; alterations in lean and fat mass, however, are poorly characterized. OBJECTIVE The objective was to quantify lean and fat mass in children and young adults with CD and in healthy control subjects, relative to height and pubertal maturation. DESIGN This cross-sectional study assessed whole-body lean and fat mass by using dual-energy X-ray absorptiometry in 104 subjects with CD and in 233 healthy control subjects aged 4-25 y. Linear regression was used to determine the effect of CD on body composition and to generate sex-specific SD scores (z scores) for lean and fat mass relative to height. RESULTS Subjects with CD had lower height-for-age and BMI-for-age z scores (P < 0.001 for both) than did control subjects. CD was associated with significant deficits in lean mass after adjustment for height, age, race, and Tanner stage (P = 0.003); deficits in fat mass were not observed. The mean (+/-SD) lean mass-for-height and fat mass-for-height z scores in the subjects with CD were -0.61 +/- 0.92 and -0.04 +/- 0.86, respectively. Within the control group, fat mass-for-height was positively correlated with lean mass-for height (r = 0.41, P < 0.0001); this association was absent in the subjects with CD. CONCLUSIONS Children and young adults with CD had significant deficits in lean mass but preserved fat mass, which is consistent with cachexia. Further research is needed to identify physical activity, nutritional, and antiinflammatory interventions to improve body composition in persons with CD.

Dual-Energy X-ray Aborptiometry Assessment in Children and Adolescents with Diseases that May Affect the Skeleton: The 2007 ISCD Pediatric Official Positions

The Task Force focusing on the use of dual energy X-ray absorptiometry (DXA) in children and adolescents with diseases that may affect the skeleton reviewed over 300 articles to establish the basis for the Official Positions. A significant number of studies used DXA-based outcome measures to assess the effects of specific interventions and charted the natural history of incremental changes in bone size and mass in specific disease states in children. However, the utility of DXA in clinical practice has not been evaluated systematically, in large part due to the lack of a workable definition for childhood osteoporosis. Thus, in combination with the Official Positions addressing the diagnosis of osteoporosis in children, and the reporting of DXA results in children, this document presents clear guidelines from which clinicians and researchers alike can work. This report delineates a set of disorders in which it is appropriate to use DXA as part of the comprehensive assessment of skeletal health in children and adolescents, and provides guidance concerning the initiation of assessment and the frequency of monitoring. Importantly, this document also highlights significant gaps in our knowledge, emphasizing areas for future research.

Determinants of changes in linear growth and body composition in incident pediatric Crohn's disease.

BACKGROUND & AIMS Pediatric Crohns disease (CD) is associated with growth, lean mass (LM), and fat mass (FM) deficits. This study assessed and identified determinants of changes in height and body composition in children with CD following. METHODS Whole-body LM and FM were assessed using dual-energy x-ray absorptiometry in 78 CD subjects at diagnosis, 6, 12, and a median of 43 months (range, 24-63) later. Race- and sex-specific Z scores for lean mass (LM-ht-Z) and fat mass (FM-ht-Z) relative to height were derived using reference data in >900 controls. Serum cytokines and growth factors were measured, and quasi-least squares regression was used to identify determinants of changes in height and body composition. RESULTS LM-ht-Z and FM-ht-Z (both P<.005) improved significantly after diagnosis; however, female patients had persistent LM deficits vs controls (-0.50+/-1.02, P<.05). Serum interleukin-6, tumor necrosis factor-alpha, and lipopolysaccharide binding protein decreased significantly (all P<.001). Greater increases in LM-ht-Z were associated with infliximab therapy (P<.05), increases in albumin (P<.001) and decreases in erythrocyte sedimentation rate (P<.05), interleukin-6 (P<.005), and lipopolysaccharide binding protein (P<.05). Greater increases in FM-ht-Z were associated with glucocorticoid, methotrexate, and infliximab therapy, and increases in albumin (P<.05) and growth hormone binding protein (P<.05). Overall, height-Z did not improve; however, greater increases in insulin-like growth factor-1 (P<.05) and decreases in tumor necrosis factor-alpha (P<.05), interleukin-6 (P<.05), and lipopolysaccharide binding protein (P<.05) levels were associated with increases in height-Z. CONCLUSIONS Immune-mediated mechanisms contribute to growth and body composition deficits in CD. Therapies should target these deficits.

Hypovitaminosis D is Associated with Greater Body Mass Index and Disease Activity in Pediatric Systemic Lupus Erythematosus

OBJECTIVES To determine whether pediatric systemic lupus erythematosus (SLE) is associated with alterations in the vitamin D-parathyroid hormone (PTH) axis and to assess the relation between vitamin D deficiency and SLE activity. STUDY DESIGN 25-hydroxy vitamin D [25(OH)D], 1,25-dihydroxy vitamin D [1,25(OH)2D], and intact PTH were measured in subjects with SLE (n = 38) and healthy controls (n = 207), ages 5 to 21 years. Vitamin D status and its relation with disease activity were assessed using multivariable logistic and linear regression. RESULTS Severe vitamin D deficiency (25(OH)D <10 ng/ml) was observed in a significantly higher proportion of subjects with SLE (36.8% vs 9.2%, P < .001). In SLE, the odds ratio (OR) for severe deficiency was 2.37 (P = .09), adjusting for age, sex, race, and season. However, for each 1 SD greater body mass index (BMI) z-score, 25(OH)D levels were 4.2 ng/mL lower (P = .01) in SLE, compared with controls. Adjusting for 25(OH)D levels, SLE was associated with significantly lower 1,25(OH)2D (P < .001) and intact PTH levels (P = .03). Greater SLE disease activity index scores were observed in those with 25(OH)D <20 ng/mL (P = .01). CONCLUSIONS SLE was associated with vitamin D deficiency, particularly among those subjects with SLE who were overweight. Future studies should assess the effect of vitamin D supplementation on skeletal and nonskeletal outcomes in SLE.

Childhood onset arthritis is associated with an increased risk of fracture : a population based study using the General Practice Research Database

Background: Childhood onset arthritis is associated with low bone mass and strength. Objective: To determine whether childhood onset arthritis is associated with greater fracture risk. Methods: In a retrospective cohort study all subjects with onset of arthritis between 1 and 19 years of age in the United Kingdom General Practice Research Database were identified. As controls, all sex and age matched subjects from a practice that included a subject with arthritis were included. Incidence rate ratios (IRRs) for first fracture were generated using Mantel-Haenszel methods and Poisson regression. Results: 1939 subjects with arthritis (51% female) and 207 072 controls (53% female) were identified. The median age at arthritis diagnosis was 10.9 years. A total of 129 (6.7%) first fractures were noted in subjects with arthritis compared with 6910 (3.3%) in controls over a median follow up of 3.90 and 3.95 years in the subjects with arthritis and controls, respectively. The IRR (95% confidence interval) for first fracture among subjects with arthritis, compared with controls, according to the age at the start of follow up were 1.49 (0.91 to 2.31) for age <10 years, 3.13 (2.21 to 4.33) at 10–15 years, 1.75 (1.18 to 2.51) at 15–20 years, 1.40 (0.91 to 2.08) at 20–45 years, and 3.97 (2.23 to 6.59) at >45 years. Conclusions: Childhood onset arthritis is associated with a clinically significant increased risk of fracture in children, adolescents and, possibly, adults. Studies are urgently needed to characterise the determinants of structural bone abnormalities in childhood arthritis and devise prevention and treatment strategies.

Divergent Effects of Glucocorticoids on Cortical and Trabecular Compartment BMD in Childhood Nephrotic Syndrome

Glucocorticoid (GC) effects on skeletal development have not been established. The objective of this pQCT study was to assess volumetric BMD (vBMD) and cortical dimensions in childhood steroid‐sensitive nephrotic syndrome (SSNS), a disorder with minimal independent deleterious skeletal effects. Tibia pQCT was used to assess trabecular and cortical vBMD, cortical dimensions, and muscle area in 55 SSNS (age, 5–19 yr) and >650 control participants. Race‐, sex‐, and age‐, or tibia length‐specific Z‐scores were generated for pQCT outcomes. Bone biomarkers included bone‐specific alkaline phosphatase and urinary deoxypyridinoline. SSNS participants had lower height Z‐scores (p < 0.0001) compared with controls. In SSNS, Z‐scores for cortical area were greater (+0.37; 95% CI = 0.09, 0.66; p = 0.01), for cortical vBMD were greater (+1.17; 95% CI = 0.89, 1.45; p < 0.0001), and for trabecular vBMD were lower (−0.60; 95% CI, = −0.89, −0.31; p < 0.0001) compared with controls. Muscle area (+0.34; 95% CI = 0.08, 0.61; p = 0.01) and fat area (+0.56; 95% CI = 0.27, 0.84; p < 0.001) Z‐scores were greater in SSNS, and adjustment for muscle area eliminated the greater cortical area in SSNS. Bone formation and resorption biomarkers were significantly and inversely associated with cortical vBMD in SSNS and controls and were significantly lower in the 34 SSNS participants taking GCs at the time of the study compared with controls. In conclusion, GCs in SSNS were associated with significantly greater cortical vBMD and cortical area and lower trabecular vBMD, with evidence of low bone turnover. Lower bone biomarkers were associated with greater cortical vBMD. Studies are needed to determine the fracture implications of these varied effects.