Abnormalities in serum osteocalcin values in children with chronic rheumatic diseases

Bone health in idiopathic inflammatory myopathies

OBJECTIVE

To review the extant literature relating to bone health in the idiopathic inflammatory myopathies (IIM) including both adult and juvenile patients.

METHODS

A PubMed search® identified relevant studies from 1966 to 2020 in accordance with PRISMA guidelines. Two independent reviewers screened and extracted the abstracts/full manuscripts, and a third author was consulted in the case of disagreement.

RESULTS

We identified 37 articles (3 review articles, 2 RCTs, 9 cross-sectional, 16 cohort and 7 case-control studies). The prevalence of osteopenia (n = 7) ranges from 7 to 75% and osteoporosis (n = 7) between 13% to 27%. The prevalence of vertebral fractures ranged from 11 to 75%. Systemic inflammation likely contributes to reduced bone mineral density (BMD) in children with IIM but data is currently lacking in adult patients. Association between with impaired BMD and Vitamin D or calcium intake and physical activity has not been demonstrated in IIM. There is no clear consensus regarding the impact of age, menopause or BMI on bone health. Gender, smoking status, disease activity and inflammatory markers are not obvious independent predictors of low BMD. Several studies have demonstrated that glucocorticoids are associated with an increased risk of low BMD. There are no specific guidelines relating to the management of bone health in adult and juvenile patients with IIM.

CONCLUSION

Both adult and juvenile patients with IIM are at high risk of impaired bone health and fracture. The mechanisms behind this are likely multifactorial including systemic inflammation, glucocorticoid treatment, reduced mobility and impaired calcium/vitamin D homeostasis. There are a lack of guidelines and studies relating to the screening, prevention and treatment of impaired bone health in adult and juvenile patients with IIM. Future research is required to understand the complexity of bone health in IIM including to develop much needed disease-specific management recommendations.

Calcinosis Biomarkers in Adult and Juvenile Dermatomyositis

Dermatomyositis (DM) is a rare idiopathic inflammatory myopathy characterized by muscle weakness and cutaneous manifestations in adults and children. Calcinosis, a complication of DM, is the abnormal deposition of insoluble calcium salts in tissues, including skin, subcutaneous tissue, tendons, fascia, and muscle. Calcinosis is more commonly seen in juvenile DM (JDM), but also develops in adult DM. Although the mechanism of calcinosis remains unclear, several pathogenic hypotheses have been proposed, including intracellular accumulation of calcium secondary to an alteration of the cellular membrane by trauma and inflammation, local vascular ischemia, dysregulation of mechanisms controlling the deposition and solubility of calcium and phosphate, and mitochondrial damage of muscle cells. Identifying calcinosis biomarkers is important for early disease detection and risk assessment, and may lead to novel therapeutic targets for the prevention and treatment of DM-associated calcinosis. In this review, we summarize myositis autoantibodies associated with calcinosis in DM, histopathology and chemical composition of calcinosis, genetic and inflammatory markers that have been studied in adult DM and JDM-associated calcinosis, as well as potential novel biomarkers.

Systemic and Tissue Inflammation in Juvenile Dermatomyositis: From Pathogenesis to the Quest for Monitoring Tools

Juvenile Dermatomyositis (JDM) is a systemic immune-mediated disease of childhood, characterized by muscle weakness, and a typical skin rash. Other organ systems and tissues such as the lungs, heart, and intestines can be involved, but may be under-evaluated. The inflammatory process in JDM is characterized by an interferon signature and infiltration of immune cells such as T cells and plasmacytoid dendritic cells into the affected tissues. Vasculopathy due to loss and dysfunction of endothelial cells as a result of the inflammation is thought to underlie the symptoms in most organs and tissues. JDM is a heterogeneous disease, and several disease phenotypes, each with a varying combination of affected tissues and organs, are linked to the presence of myositis autoantibodies. These autoantibodies have therefore been extensively studied as biomarkers for the disease phenotype and its associated prognosis. Next to identifying the JDM phenotype, monitoring of disease activity and disease-inflicted damage not only in muscle and skin, but also in other organs and tissues, is an important part of clinical follow-up, as these are key determinants for the long-term outcomes of patients. Various monitoring tools are currently available, among which clinical assessment, histopathological investigation of muscle and skin biopsies, and laboratory testing of blood for specific biomarkers. These investigations also give novel insights into the underlying immunological processes that drive inflammation in JDM and suggest a strong link between the interferon signature and vasculopathy. New tools are being developed in the quest for minimally invasive, but sensitive and specific diagnostic methods that correlate well with clinical symptoms or reflect local, low-grade inflammation. In this review we will discuss the types of (extra)muscular tissue inflammation in JDM and their relation to vasculopathic changes, critically assess the available diagnostic methods including myositis autoantibodies and newly identified biomarkers, and reflect on the immunopathogenic implications of identified markers.

Vitamin D and juvenile idiopathic arthritis

BACKGROUND

Vitamin D has been implicated in the pathogenesis of autoimmune diseases. While the roles of vitamin D in other autoimmune diseases have been investigated, less is known about the role of vitamin D in chronic childhood arthritis.

MAIN BODY

This review summarizes and evaluates evidence relating to 25-hydroxyvitamin D (25(OH)D) and chronic childhood arthritis. A scoping literature review was conducted using Ovid Medline, Ovid Embase, Cumulative Index to Nursing and Allied Health Literature, Web of Science and Scopus. Further, we geo-mapped the results of the studies to identify the patterns of the association between vitamin D and chronic childhood arthritis across the globe. Of 38 studies reporting 25(OH)D concentrations in childhood chronic arthritis, 32 (84.2%) reported that a significant number of children had suboptimal (< 75 nmol/L) status.

CONCLUSION

The data indicate suboptimal vitamin D status in children with chronic arthritis. Further, the association between low vitamin D and increased arthritis activity follow a north-south geographical gradient.

Protecting Bone Health in Pediatric Rheumatic Diseases: Pharmacological Considerations

Bone health in children with rheumatic conditions may be compromised due to several factors related to the inflammatory disease state, delayed puberty, altered life style, including decreased physical activities, sun avoidance, suboptimal calcium and vitamin D intake, and medical treatments, mainly glucocorticoids and possibly some disease-modifying anti-rheumatic drugs. Low bone density or even fragility fractures could be asymptomatic; therefore, children with diseases of high inflammatory load, such as systemic onset juvenile idiopathic arthritis, juvenile dermatomyositis, systemic lupus erythematosus, and those requiring chronic glucocorticoids may benefit from routine screening of bone health. Most commonly used assessment tools are laboratory testing including serum 25-OH-vitamin D measurement and bone mineral density measurement by a variety of methods, dual-energy X-ray absorptiometry as the most widely used. Early disease control, use of steroid-sparing medications such as disease-modifying anti-rheumatic drugs and biologics, supplemental vitamin D and calcium, and promotion of weight-bearing physical activities can help optimize bone health. Additional treatment options for osteoporosis such as bisphosphonates are still controversial in children with chronic rheumatic diseases, especially those with decreased bone density without fragility fractures. This article reviews common risk factors leading to compromised bone health in children with chronic rheumatic diseases and discusses the general approach to prevention and treatment of bone fragility.

Vitamin D—update for the pediatric rheumatologists

Vitamin D, upon its discovery one century ago, was classified as a vitamin. This classification still greatly affects our perception about its biological role. 1,25(OH)2D (now known as the D hormone) is a pleiotropic steroid hormone that has multiple biologic effects. It is integral to the regulation of calcium homeostasis and bone turnover as well as having anti-proliferative, pro-differentiation, anti-bacterial, immunomodulatory and anti-inflammatory properties within the body in various cells and tissues. Vitamin D (cholecalciferol) should be considered a nutritional substrate that must be ingested or synthesized in sufficient amounts for the further synthesis of the very important regulatory steroid hormone (D hormone), especially in patients with pediatric rheumatic diseases (PRD). Vitamin D insufficiency or deficiency was shown to be pandemic and associated with numerous chronic inflammatory and malignant diseases and even with increased risk of mortality. Several studies have demonstrated that a high percentage of children with pediatric rheumatic diseases (PRD-e.g., JIA, jSLE) have a vitamin D deficiency or insufficiency which might correlate with disease outcome and flares. Glucocorticoids used to treat disease may have a regulatory effect on vitamin D metabolism which can additionally aggravate bone turnover in PRD. An effort to define the optimal serum 25(OH)D concentrations for healthy children and adults was launched in 2010 but as of now there are no guidelines about supplementation in PRD. In this review we have tried to summarize the strong evidence now suggesting that as the knowledge of the optimal approach to diagnosis and treatment PRD has evolved, there is also an emerging need for vitamin D supplementation as an adjunct to regular disease treatment. So in accordance with new vitamin D recommendations, we recommend that a child with rheumatic disease, especially if treated with steroids, needs at least 2-3 time higher doses of vitamin D than the dose recommended for age (approximately 2000 UI/day). Vitamin D supplementation has become an appealing and important adjunct treatment option in PRD.

Determinants of vitamin D levels in children, adolescents, and young adults with juvenile idiopathic arthritis

OBJECTIVE

Deficiency of 25-hydroxyvitamin D [25(OH)D] is reported to be common in patients with rheumatoid arthritis (RA); data in patients with juvenile idiopathic arthritis (JIA) are inconsistent. We assessed serum 25(OH)D in children, adolescents and young adults with JIA, in order to identify the risk factors for vitamin D deficiency in patients with JIA.

METHODS

We evaluated 152 patients with JIA: 115 female, 37 male, mean age 16.2 ± 7.4 yrs; evaluated by onset type, 96 had oligoarticular, 35 polyarticular, 7 systemic, and 14 enthesitis-related arthritis (ERA). Patients were compared with a control group matched for sex and age. All patients and controls underwent laboratory tests of plasma 25(OH)D, parathyroid hormone (PTH), calcium, phosphorus, and bone alkaline phosphatase levels, and dual-energy x-ray absorptiometry examination.

RESULTS

Patients with JIA showed significantly reduced 25(OH)D levels compared to controls (p < 0.001), even divided into subtypes (oligoarticular, p < 0.05; polyarticular, p < 0.005; systemic, p < 0.001; ERA, p < 0.005). Patients with active disease and/or frequent relapses had significantly reduced 25(OH)D levels compared to patients with no active disease and no frequent flares (p < 0.005, respectively). Nevertheless, JIA patients had significantly higher PTH levels compared to controls (p < 0.0001). JIA patients with 25(OH)D deficiency showed a significantly lower bone mineral apparent density than those with normal 25(OH)D levels (p < 0.001).

CONCLUSION

JIA patients have reduced 25(OH)D and higher PTH values. This may explain at least in part why JIA patients, despite more effective current drugs, do not achieve bone-normal condition over time. JIA patients with more severe disease could require higher supplementation of vitamin D to maintain normal 25(OH)D serum levels. Longterm studies are needed to investigate the relationship between serum 25(OH)D levels and disease activity in JIA.

Disease activity, proteinuria, and vitamin D status in children with systemic lupus erythematosus and juvenile dermatomyositis

OBJECTIVE

To evaluate relationships among vitamin D, proteinuria, and disease activity in pediatric systemic lupus erythematosus (SLE) and juvenile dermatomyositis (JDM).

STUDY DESIGN

Multiple linear regression was used to associate subject-reported race, sunscreen use, and vitamin D intake with physician-assessed disease activity and serum 25-hydroxyvitamin D (25[OH]D) in 58 subjects with pediatric SLE (n=37) or JDM (n=21). Serum 25(OH)D was correlated with urinary vitamin D binding protein/creatinine ratio (DBP/C) and other indicators of proteinuria.

RESULTS

Serum 25(OH)D levels in subjects with SLE were inversely associated with the natural log of urinary DBP/C (r=-0.63, P<.001) and urine protein to creatinine ratio (r=-0.60, P<.001), with an adjusted mean 10.9-ng/mL (95% CI, 5.1-16.8) decrease in 25(OH)D for those with proteinuria. Excluding subjects with proteinuria, serum 25(OH)D levels were inversely associated with disease activity in JDM, but not in SLE. Overall, 66% of all subjects were taking concurrent corticosteroids, but this was not associated with 25(OH)D levels.

CONCLUSIONS

Low serum 25(OH)D in patients with SLE is associated with proteinuria and urinary DBP. Vitamin D deficiency is associated with disease activity in patients with JDM and SLE; this relationship in SLE may be confounded by proteinuria.

Vitamin D supplementation in the pediatric rheumatology clinic

Vitamin D is capturing the attention of healthy and chronically ill populations for its potential skeletal and nonskeletal benefits. New information suggesting a role in immune modulation has led to a surge of interest among rheumatologists. Although the epidemiologic data are limited, it appears that many children with rheumatic conditions are at risk of vitamin D deficiency. However, understanding this phenomenon requires an appreciation for how vitamin D status is assessed, and options for supplementation. Although a “more-is-better” attitude is tempting when considering the medicinal effects of a nutritional supplement, we suggest a cautious approach and suggest that further studies are needed to clarify the potential benefits and risks among children with rheumatic conditions.

25-Hydroxyvitamin D Levels and Vitamin D Deficiency in Children with Rheumatologic Disorders and Controls

Objective.

To evaluate the prevalence of vitamin D deficiency, as well as factors associated with serum 25-hydroxyvitamin D [25(OH)D] levels, in children attending a pediatric rheumatology clinic, and to determine whether there was a difference in serum 25(OH)D levels and in vitamin D deficiency between children with autoimmune disorders and nonautoimmune conditions.

Methods.

Cross-sectional analysis of serum 25(OH)D levels of patients between the ages of 2 and 19 years, seen between November 2008 and October 2009.

Results.

A total of 254 patients were studied (169 autoimmune disorders, 85 nonautoimmune conditions). The mean age of study patients was 12.3 years; 67% were female and 80% were white. In the autoimmune disorders group, 23% had vitamin D deficiency [serum 25(OH)D < 20 ng/ml], and in the nonautoimmune conditions group 14% were vitamin D deficient. The average level of serum 25(OH)D was 28.6 (± 11) ng/ml (range 2 to 59). Age, ethnicity, body mass index, use of supplements, and season were significantly associated with serum levels of 25(OH)D (all p ≤ 0.02). The OR of patients with autoimmune disorders being vitamin D deficient was 2.3, in relation to patients with nonautoimmune conditions (p = 0.04).

Conclusion.

Twenty percent of patients attending a pediatric rheumatology clinic were vitamin D deficient. Patients with autoimmune disorders were more likely to be vitamin D deficient than patients with nonautoimmune conditions. Screening of serum 25(OH)D levels should be performed for patients with autoimmune disorders.

Does vitamin D affect risk of developing autoimmune disease?: a systematic review

OBJECTIVES

We evaluated the epidemiologic evidence that vitamin D may be related to human autoimmune disease risk.

METHODS

PubMed, limited to English from inception through April 2010, was searched using keywords: "vitamin D," "autoimmune," and autoimmune disease names. We summarized in vitro, animal, and genetic association studies of vitamin D in autoimmune disease pathogenesis. We sorted epidemiologic studies by design and disease and performed a systematic review of (a) cross-sectional data concerning vitamin D level and autoimmune disease; (b) interventional data on vitamin D supplementation in autoimmune diseases; and (c) prospective data linking vitamin D level or intake to autoimmune disease risk.

RESULTS

Vitamin D has effects on innate and acquired immune systems, and vitamin D receptor polymorphisms have been associated with various autoimmune diseases. In experimental animal models, vitamin D supplementation can prevent or forestall autoimmune disease. Of 1446 studies identified and screened, 76 studies examined vitamin D levels in autoimmune disease patients, particularly with active disease, and compared with controls. Nineteen observational or interventional studies assessed the effect of vitamin D supplementation as therapy for various autoimmune diseases (excluding psoriasis and vitiligo) with a range of study approaches and results. The few prospective human studies performed conflict as to whether vitamin D level or intake is associated with autoimmune disease risk. No interventional trials have investigated whether vitamin D affects human autoimmune disease risk.

CONCLUSIONS

Cross-sectional data point to a potential role of vitamin D in autoimmune disease prevention, but prospective interventional evidence in humans is still lacking.

Vitamin D and autoimmune rheumatologic disorders

Vitamin D levels depend on many variables, including sun exposure, age, ethnicity, body mass index, use of medications and supplements. A much higher oral vitamin D intake than the current guidelines is necessary to maintain adequate circulating 25(OH)D levels in the absence of UVB radiation of the skin. In addition to the traditional known metabolic activities, vitamin D has been shown to modulate the immune system, and its deficiency has been linked to the development of several autoimmune disorders including type 1 diabetes and multiple sclerosis. Experimental use of vitamin D has revealed a novel role in the immunopathogenesis of autoimmune diseases. Disorders such as systemic lupus erythematosus, rheumatoid arthritis, Behçet's, polymyositis/dermatomyositis and systemic scleroderma have all been associated to some extent to vitamin D deficiency. If vitamin D deficiency occurs at a higher rate in patients with autoimmune disorders, then appropriate supplementation may be indicated.

Vitamin D deficiency in patients with active systemic lupus erythematosus

We investigated the effects of disease activity on bone metabolism in 36 patients with systemic lupus erythematosus (SLE). Changes in bone remodeling were not explained by corticosteroid use. A high prevalence of 25OHD deficiency in SLE patients indicates the need for vitamin D replacement, mainly during high disease activity periods.

INTRODUCTION

We investigated the effects of SLE disease activity on bone metabolism, their relation to inflammatory cytokines and vitamin D levels.

METHODS

We performed a cross-sectional analysis of 36 SLE patients classified according to the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) in high activity (group I: 12 patients, mean age 29.6 years) or in minimal activity (group II: 24 patients, mean age 30.0 years), and compared them to normal controls (group III: 26 women, 32.8 years). Serum calcium, phosphorus, parathyroid and sex hormones, bone remodeling markers, interleukin (IL)-6, soluble IL-6 receptor (sIL-6R), IL-1, tumor necrosis factor-alpha (TNF), 25-hydroxivitamin D (25OHD), and 1,25-dihydroxyvitamin D3 were measured, plus bone mineral density.

RESULTS

All cytokines were significantly higher in SLE groups; IL-6 could differentiate SLE patients from controls. In group I, 25OHD levels were lower (P < 0.05), which was related to the SLEDAI (R = -0.65, P < 0.001). In multiple regression analysis, the 25OHD level was associated with SLEDAI, osteocalcin and bone-specific alkaline phosphatase. The SLEDAI score was positively correlated with all measured cytokines and especially TNF (R = 0.75, P < 0.001).

CONCLUSIONS

SLE patients demonstrated changes in bone remodeling strongly related to disease activity. A high prevalence of 25OHD deficiency was observed in SLE patients, indicating the need for vitamin D replacement.

Biochemical markers of bone turnover associated with calcium supplementation in children with juvenile rheumatoid arthritis: results of a double-blind, placebo-controlled intervention trial

OBJECTIVE

To determine the effects of calcium supplementation on bone physiology in corticosteroid-free children with juvenile rheumatoid arthritis (JRA) by measuring serum and urinary bone-related hormones, minerals, and markers of bone formation and resorption.

METHODS

In this double-blind trial, patients were randomized to receive daily oral supplementation with 1,000 mg of calcium and 400 IU of vitamin D or with placebo and 400 IU of vitamin D for 24 months. The effect of calcium supplementation on bone physiology was determined periodically using markers of bone turnover.

RESULTS

One hundred ninety-eight patients met the inclusion criteria and were followed up in the study. At baseline, there were no differences in markers of bone turnover between the groups. Patients with < or = 4 joints with active disease had higher serum levels of calcium and parathyroid hormone (PTH). Calcium-treated patients with < or =4 joints with active disease had lower levels of osteocalcin (OC). At followup, levels of 1,25-dihydroxyvitamin D3, PTH, OC, and urine phosphorus were lower in the group receiving calcium supplementation. Hypercalciuria, as determined by the urinary calcium-to-creatinine ratio, was not noted in 24-hour urine studies.

CONCLUSION

Levels of markers of bone physiology were significantly decreased in children with JRA receiving calcium supplementation. The physiologic changes were noted as early as 12 months into calcium supplementation. The hypercalciuria noted on spot testing of the urinary calcium-to-creatinine ratio was not demonstrated on further evaluation, nor did it lead to renal pathology. These findings suggest that the calcium supplementation met physiologic needs and caused an increased calcium loss in urine.

Percent true calcium absorption, mineral metabolism, and bone mass in children with arthritis: effect of supplementation with vitamin D3 and calcium

OBJECTIVE

To assess whether percent true calcium absorption (alpha) is normal and whether supplementation with placebo, vitamin D3 (2,000 IU/day), calcium (1,000 mg/day), or vitamin D3 plus calcium improves alpha, mineral metabolism, or bone mass accrual in children with arthritis.

METHODS

Eighteen children received all 4 treatments, each for 6 months, in 4 different, randomly assigned orders. Changes in levels of 25-hydroxyvitamin D (25[OH]D), 1,25-dihydroxyvitamin D (1,25[OH]2D), parathyroid hormone, bone turnover markers, and minerals and in bone mineral content were measured. Calcium absorption was determined with a dual stable isotope method using 48Ca administered intravenously and 46Ca administered orally, and measuring 48Ca, 46Ca, and 42Ca in a 24-hour urine specimen by high-resolution inductively coupled plasma mass spectroscopy. Wilcoxon's signed rank test was used both to identify significant change over the treatment period with a given regimen and to compare change with an experimental treatment versus change with placebo.

RESULTS

Percent true calcium absorption was in the lower-normal range and did not differ by treatment (mean+/-SD 28.3+/-20.2% with placebo, 26.1+/-12.1% with calcium, 19.2+/-11.7% with vitamin D3, and 27.1+/-16.5% with vitamin D3 plus calcium). With vitamin D3 and vitamin D3 plus calcium treatment, 25(OH)D levels were increased and 1,25(OH)2D levels were maintained. Serum calcium levels were increased only with vitamin D3 and vitamin D3 plus calcium treatment. Levels of bone turnover markers and increases in bone mineral content did not differ by treatment.

CONCLUSION

The findings of this study indicate that percent true calcium absorption is low-normal in children with arthritis. Vitamin D3 at 2,000 IU/day increases serum 25(OH)D and calcium levels but does not improve bone mass accretion. Calcium at 1,000 mg/day also failed to improve bone mass.

Serum from children with polyarticular juvenile idiopathic arthritis (pJIA) inhibits differentiation, mineralization and may increase apoptosis of human osteoblasts "in vitro"

We examined the effects of polyarticular juvenile idiopathic arthritis (pJIA) serum on proliferation, differentiation, mineralization, and apoptosis of human osteoblast cells (hOb) in culture. The hOb were cultured with 10% serum from active pJIA and healthy controls (CT) and were tested for DNA synthesis, alkaline phosphatase (AP) activity, osteocalcin (OC) secretion, calcium levels, caspase 3 activity, and DNA fragmentation. None of the patients had used glucocorticoids for at least 1 month before the study, or any other drug that can affect bone mineral metabolism. Human inflammatory cytokine levels (IL-6, IL-8, IL-10, IL-1beta, TNF-alpha, and IL-12p70) were measured in pJIA and CT sera. Low levels of AP activity was observed in pJIA cultures compared with CT cultures (67.16 +/- 53.35 vs 100.11 +/- 50.64 mumol p-nitrophenol/h(-1) mg(-1) protein, P = 0.008). There was also a significant decrease in OC secretion (9.23 +/- 5.63 vs 12.82 +/- 7.02 ng/mg protein, P = 0.012) and calcium levels (0.475 +/- 0.197 vs 0.717 +/- 0.366 mmol/l, P = 0.05) in pJIA hOb cultures. No difference was observed in cell proliferation (323.56 +/- 108.23 vs 328.91 +/- 88.03 dpm/mg protein, P = 0.788). Osteoblasts cultured with JIA sera showed lower levels of DNA and increased fragmentation than osteoblasts cultured with CT sera. pJIA sera showed higher IL-6 values than CT (21.44 +/- 9.31 vs 3.58 +/- 2.38 pg/ml, P < 0.001), but no difference was observed related to IL-8, IL-10, IL-1beta, TNF-alpha, and IL-12p70 between pJIA and controls. This study suggests that serum from children with pJIA inhibits differentiation, mineralization and may increase apoptosis of hOb cultures, and inflammatory cytokines such as IL-6 might be a mechanism in this find. These results may represent an alternative therapeutic target for prevention and treatment of bone loss in JIA.

Hypercalcemia in rheumatoid arthritis: relationship with disease activity and bone metabolism

To investigate the relationship between ionized calcium and disease activity, parameters of bone metabolism and bone mineral density (BMD) at the lumbar spine (BMD-LS) and the femoral neck (BMD-FN) measured by dual X-ray absorptiometry in rheumatoid arthritis (RA). In 146 patients with RA, the following parameters were investigated: serum levels of ionized calcium, total calcium, vitamin D metabolites 25-hydroxyvitamin D3 (25D3) and 1,25-dihydroxyvitamin D3 (1,25D3), intact parathyroid hormone (iPTH), interleukin-6, osteocalcin, erythrocyte sedimentation rate (ESR) and c-reactive protein (CRP); renal excretion of pyridinolin (PYD)- and desoxypyridinolin (DPD)-crosslinks. A total of 30.1% of the patients were hypercalcemic (ionized calcium >1.30 mmol/l). In comparison with normocalcemic patients, those with hypercalcemia had significantly higher ESR (P<0.01) and CRP values (P<0.05) and significantly lower serum levels of both iPTH (P<0.01) and 1,25D3 (P<0.05) and a significantly lower BMD-LS (P<0.05). The results indicate that a substantial part of RA patients is hypercalcemic. Hypercalcemia is associated with high disease activity and may contribute to suppression of PTH secretion and vitamin D hormone synthesis. High levels of ionized calcium may be a reflection of disease-activity-related systemic bone loss, and could be a predictor of BMD at the lumbar spine in RA.

Frequency of osteopenia in children and young adults with childhood-onset systemic lupus erythematosus

OBJECTIVE

To determine the frequency of osteopenia in patients with childhood-onset systemic lupus erythematosus (SLE) compared with that in healthy matched controls, and to evaluate the relationship between disease-related variables and bone mineral mass.

METHODS

Bone mineral density (BMD) and bone mineral content (BMC) were measured in a cohort of 70 patients with childhood-onset SLE (mean +/- SD disease duration 10.8 +/- 8.3 years, mean +/- SD age 26.4 +/- 9.9 years) and 70 age- and sex-matched healthy controls. BMD and BMC of the femoral neck, lumbar spine, total body, and distal one-third of the radius were measured by dual x-ray absorptiometry. We investigated the relationship between BMC and the following disease variables: cumulative dose of corticosteroids, organ damage, current use of corticosteroids, use of cyclophosphamide, age at disease onset, and disease activity at the time of diagnosis. Biochemical markers of bone metabolism were also measured.

RESULTS

BMD values for the lumbar spine and femoral neck were significantly lower in patients than in healthy controls. The reduction in BMD of the lumbar spine was significantly greater than that of the total body. In multiple linear regression analyses, a higher cumulative corticosteroid dose was significantly associated with lower BMC of the lumbar spine and femoral neck. Decreased lumbar spine BMC was also related to male sex.

CONCLUSION

The frequency of osteopenia was higher in patients with childhood-onset SLE than in matched controls. The lumbar spine was the most seriously affected skeletal site, followed by the femoral neck. The cumulative dose of corticosteroids was shown to be an important explanatory variable for BMC values in the lumbar spine and femoral neck.

Bone mineral density of Brazilian girls with juvenile dermatomyositis

We measured bone mineral density (BMD) in girls with juvenile dermatomyositis (JDM) considering multiple factors in order to determine if it could be used as a predictor of reduction in bone mass. A cross-sectional study of lumbar spine BMD (L2-L4) was conducted on 10 girls aged 7-16 years with JDM. A group of 20 age-matched healthy girls was used as control. Lumbar spine BMD was measured by dual-energy X-ray absorptiometry. Weight, height and pubertal Tanner stage were determined in all patients and controls. Duration of disease and mean daily and cumulative steroid doses were calculated for all patients on the basis of their medical charts. JDM activity was determined on the basis of the presence of muscle weakness, cutaneous vasculitis and/or elevation of serum concentration of one or more skeletal muscle enzymes. Seven patients demonstrated osteopenia or osteoporosis. Lumbar BMD was significantly lower in the JDM patients than the age-matched healthy control girls (0.712 vs 0.878, respectively; Student t-test, P = 0.041). No significant correlation between BMD and age, height, Tanner stage, disease duration, corticosteroid use, or disease activity was observed in JDM girls, but a correlation was observed between BMD and weight (Pearson's correlation coefficient, r = 0.802). Patients with JDM may be at risk for a significant reduction in BMD that might contribute to further skeletal fragility. Our results suggest that reduced bone mass in JDM may be related to other intrinsic mechanisms in addition to steroid treatment and some aspects of the disease itself may contribute to this condition.

Musculoskeletal abnormalities of the forearm in patients with juvenile idiopathic arthritis relate mainly to bone geometry

OBJECTIVE

Alterations of the skeletal system, including reduced bone mineral density, increased frequency of fractures, and changes in markers of bone metabolism, have been described in juvenile idiopathic arthritis (JIA), but measurement of volumetric bone density and bone geometry is not possible with the techniques used in most studies. This study was undertaken to obtain a more detailed understanding of the musculoskeletal system in JIA by analyzing bone density, bone geometry, and muscle force as the most important factor in bone development.

METHODS

The technique of peripheral quantitative computed tomography was used in a cross-sectional study of 57 children with the oligoarticular, polyarticular, or systemic form of JIA. Density of trabecular and cortical bone as well as geometric parameters of bone and muscle were measured at the forearm.

RESULTS

Children in all subgroups had significantly reduced muscle cross-sectional area, which was strongly correlated with muscle force and abnormalities in geometric parameters of bone, including a significant reduction in cortical thickness. Trabecular density was affected only in the polyarticular JIA group, and cortical density was normal in all subgroups.

CONCLUSION

Our results suggest that an important problem in JIA is the lack of muscle mass and force, together with abnormal bone geometry. The thinned bony cortices might predispose to fractures even though cortical bone density itself is normal. These results might have implications with regard to therapeutic approaches to preserve musculoskeletal integrity in JIA.

Bone mineral density in juvenile dermatomyositis: assessment using dual x-ray absorptiometry

OBJECTIVE

To determine the bone mineral density (BMD) status of our juvenile dermatomyositis (DM) population and to compare the frequency of osteopenia in patients with active disease requiring corticosteroids with that in patients with inactive disease who are not receiving corticosteroids.

METHODS

Medical charts of all children diagnosed as having juvenile DM at our institution between 1989 and 1999 were reviewed for demographic and clinical data, including disease activity and duration of corticosteroid therapy. BMD measurements of the lumbar spine (L1-L4) were performed using dual x-ray absorptiometry (DXA). Z scores were calculated from the BMD data for comparison with published normative data.

RESULTS

A total of 15 patients were assessed: 10 with active disease, and 5 with inactive disease who had not taken corticosteroids for an average of 6.0 years (range 3.4-8.1 years). Baseline BMD measurements demonstrated osteopenia or frank osteoporosis in the majority of patients, including 6 of the 10 patients with active disease and 4 of the 5 patients whose disease was in remission. Fourteen patients had serial BMD measurements. Persistent or worsening osteopenia was documented in all patients who had ongoing active disease, except for 3 patients who had been treated with bisphosphonates because of vertebral compression fractures.

CONCLUSION

Osteopenia is common in patients with juvenile DM, and it usually worsens with ongoing disease. It can persist for many years after the disease enters remission. Bisphosphonates appeared to beneficially affect bone mineralization in our patients. Treatment to prevent the long-term complications of osteoporosis in patients with juvenile DM should be considered and requires further study.

Factors playing a role in the development of decreased bone mineral density in juvenile chronic arthritis

OBJECTIVE

The aims of this study were to evaluate bone mineral density (BMD) in patients with juvenile chronic arthritis (JCA), compare them with healthy controls, and assess the effects of disease activity and corticosteroid treatment on BMD.

METHODS

Twenty-eight patients diagnosed with JCA and 45 healthy controls were included in this study. Disease activity was determined by clinical and laboratory evaluation, Articular Disease Severity Score (ADSS), and the Juvenile Arthritis Functional Assessment Report (JAFAR). Bone mineral density of the lumbar spine was measured by dual energy X-ray absorptiometry (DEXA).

RESULTS

Patients with JCA showed significant decreases in BMD compared with healthy controls. The JCA patients treated with corticosteroids showed significantly lower BMDs than the healthy control group. Age of the patients and age of onset were found to correlate with BMD.

CONCLUSION

Our study showed that glucocorticoids were involved in the development of osteoporosis in JCA, with many other factors affecting bone mineralization. We could not demonstrate any relationship between BMD and disease activity, but the study data suggest that early onset disease is also an important factor in the development of osteoporosis in JCA.

Bone metabolism in childhood rheumatic disease

There is an increasing appreciation among physicians about the importance of bone health in children as a potential modifiable risk factor for development of osteoporosis later in life. Many unanswered questions about normal pediatric bone health make the treatment and clinical investigation of bone disease in children with chronic rheumatic diseases challenging. Understanding normal bone biology along with the epidemiology and diagnosis of osteoporosis is the key to the understanding of the potential for abnormal bone metabolism in the juvenile rheumatic diseases.

Hepatic osteodystrophy in chronic cholestasis: evidence for a multifactorial etiology

Children with cholestatic liver disease have been thought to develop hepatic osteodystrophy resulting from vitamin D and calcium malabsorption, resulting in secondary hyperparathyroidism and osteomalacia or rickets. However, treatment with vitamin D has not always proven successful in improving the bone disturbance. The aim of our study was to determine the role of vitamin D deficiency in the pathogenesis of hepatic osteodystrophy. We studied five patients, three female and two male, ages 0.9-19 yr, with biopsy-proven chronic cholestatic liver disease and previously low serum levels of vitamin D despite oral intake of vitamin D preparations. Patients were admitted to the Clinical Research Center for 8 days for sunlight deprivation and ultraviolet light substitution and for determinations of serum 25-hyroxyvitamin D(25(OH)) D2 and -D3, osteocalcin, and type I collagen telopeptide (ICTP), the last two being markers of bone formation and resorption, respectively. Samples were taken on admission, at discharge, and 1 month later. Results demonstrated low serum levels of osteocalcin and normal circulating levels of ICTP. Admission serum 25(OH)D2 levels were uniformly low or undetectable and remained so. Admission levels of circulating 25(OH)D3 were normal or low and did not rise during ultraviolet light therapy or subsequent resumption of oral vitamin D therapy and remained low 1 month later. These results indicate that in the face of low-normal to low total 25(OH)D levels, the low osteocalcin and normal ICTP levels suggest that decreased bone formation and not increased bone resorption is the main determinant of bone loss in a subset of children with chronic cholestatic liver disease.

Vitamin D depletion following burn injury in children: a possible factor in post-burn osteopenia

BACKGROUND

Children burned > 40% total body surface area (TBSA) have chronically low bone mineral density (BMD) and increased risk for fractures and adult-onset osteoporosis. Because they are advised to avoid sunlight to prevent burn scar hyperpigmentation, we hypothesized that they develop vitamin D depletion, which could contribute to post-burn osteopenia.

METHODS

We studied 24 children, ages 5-20 years, burned > or = 40% TBSA 7.1 +/- 3.8 (SD) years, range 1.9-13.3 years, previously (n = 12) and 2.0 +/- 0.2, range 1.4-2.1 years, previously (n = 12), of which half received recombinant human growth hormone during the first post-burn year. We measured lumbar spine BMD, serum 25-hydroxyvitamin D (25(OH)D), 1,25-dihydroxyvitamin D (1,25(OH)2D), intact PTH (iPTH), and osteocalcin.

RESULTS

Serum 25(OH)D was low in 10/11 patients and 1,25(OH)2D was low in 5/11 at 7 years post-burn. Serum 25(OH)D was low in 10/12, while 1,25(OH)2D was low in 0/12 at 2 years; osteocalcin was low in 9/12 in the 7-year group; iPTH levels were in the lowest quartile in 5/12 patients at 7 years and 10/12 patients at 2 years. Serum 25(OH)D levels correlated with BMD z-scores, r = 0.53, p < 0.05, and inversely with iPTH levels, r = -0.66, p < 0.05, in the 7-year group.

CONCLUSION

Burned children have low circulating levels of 25(OH)D which correlated with BMD z-scores, suggesting that post-burn vitamin D depletion may play a role in the chronically low bone density observed in these children.

GH therapy in juvenile chronic arthritis: results of a two-year controlled study on growth and bone

Disturbance of growth frequently occurs in children suffering from juvenile chronic arthritis (JCA). Recognition of growth impairment is important because reduced final height is one of the permanent consequences. The aim of this study was to evaluate the efficacy and safety of human GH (hGH) in growth-retarded prepubertal children with JCA. Thirty-five children were tested for GH deficiency (GHD) and randomly assigned to a study and an untreated control group; five were GH deficient and were part of the GHD group. All received glucocorticoids. The study group was treated with 1 IU/kg BW.wk hGH; the GHD group was given 0.5 IU. During 2 yr of hGH treatment growth velocity and height SD score increased compared with baseline values. There was a marked increase in growth velocity in the treated groups, but also some increase in the control group. Plasma levels of IGF-I and IGF-binding protein-3 increased with GH treatment. These results suggest that hGH might be useful in the treatment of growth impairment in JCA. GH may counteract the adverse effects of glucocorticoid therapy, but its effect is dependent on the disease activity. Long-term controlled studies are needed to determine the risks and benefits of GH therapy in JCA.

Multiple stress fractures in a young girl with chronic idiopathic arthritis. Extended case report

The occurrence of stress fractures in patients with long-standing rheumatoid arthritis (RA) is widely known. Osteoporosis, corticosteroid therapy, joint stiffness, contracture, angular deformity of the joint and failed joint reconstruction--all together or separately--predispose to bone loss and stress fractures. In the present report we describe the history of a girl with juvenile idiopathic arthritis (JIA) having multiple stress fractures. The relationship between corticosteroid therapy and immobilisation in the treatment of fractures is discussed.

Osteoporosis in juvenile idiopathic arthritis

Osteoporosis is characterized by loss of both bone mass and microarchitectural integrity, resulting in an increased risk of fractures with associated morbidity and mortality. Awareness of this condition is increasing in pediatrics, including pediatric rheumatology. Reduced bone mineral density is now well recognized in children and young adults with juvenile idiopathic arthritis and is multifactorial in origin. The problems of interpretation of bone analysis techniques during childhood and adolescence are highlighted. Recent studies have reported on the use of newer methods of imaging, including quantitative ultrasound and bone single photon emission computed tomography techniques. Attempting to disentangle the relative effects of disease activity, corticosteroids, nutrition, and physical activity in the development of osteoporosis in juvenile idiopathic arthritis is the focus of several studies. Finally, early optimistic reports of the use of bisphosphonates in juvenile idiopathic arthritis are welcome additions to the growing body of literature in this area.

A pilot study on the effects of exercise in patients with systemic lupus erythematosus

OBJECTIVE

A pilot study was designed to assess the efficacy and safety of different exercise therapies on patient-reported fatigue and functional status.

METHODS

Ten patients with systemic lupus erythematosus (SLE) were randomly placed in either an aerobic exercise group (group 1: n = 5) or a range of motion/muscle strengthening (ROM/MS) exercise group (group 2: n = 5). Outcome measures assessed at baseline and the end of the study were fatigue, functional status, disease activity, cardiovascular fitness, isometric strength, bone mineral density (BMD) of the lumbar spine and femoral neck, and parathyroid hormone and osteocalcin as representative bone biochemical markers for bone resorption and bone formation, respectively.

RESULTS

Both aerobic and ROM/MS types of exercise were safe and did not worsen SLE disease activity. Patients in both exercise groups showed some improvement in fatigue, functional status, cardiovascular fitness, and muscle strength. Both groups showed increased bone turnover, but BMD was unchanged. Eighty percent of the patients met the compliance standard for the study.

CONCLUSIONS

This pilot study shows the feasibility of exercise for SLE patients. The potential value of this approach shows promise in the routine management of these patients.

Young adults with juvenile arthritis in remission attain normal peak bone mass at the lumbar spine and forearm

OBJECTIVE

To assess the impact of disease activity on acquired peak bone mass and bone turnover in young adult patients with either persistent juvenile arthritis (JA) or a history of JA (JA in remission).

METHODS

Two hundred twenty-nine patients with JA were studied after a mean +/- SD of 15.6 +/- 2.4 years in women and 14.9 +/- 2.1 years in men since disease onset. One hundred forty-five women and 84 men were over the age of 20 at the time of examination (mean +/- SD age 24.9 +/- 2.9 years for women and 25.2 +/- 3.1 years for men). Forty-one healthy women (mean +/- SD age 27.4 +/- 3.1 years) and 55 healthy men (mean +/- SD age 25.7 +/- 3.1 years) served as a reference group. Bone mineral density (BMD) was analyzed by dual x-ray absorptiometry. Serum osteocalcin concentrations and urinary concentrations of deoxypyridium (D-Pyd) were measured. Linear regression analyses were performed to evaluate the impact of disease on BMD.

RESULTS

Patients with persistent disease had significantly lower BMD compared with healthy subjects (P < 0.001 for women at all measured sites and for men at the femoral neck and total body; P < 0.05 for men at the radius and lumbar spine). Of the patients with a history of JA, only women had significantly lower BMD at the femoral neck and total body (P < 0.05). Patients with persistent JA had significantly more osteopenia and osteoporosis than healthy subjects, while patients with a history of JA had more frequent osteopenia only in the total body. Weight, urinary concentration of D-Pyd, and belonging to the patient group significantly affected BMD at all measured sites in the entire study population, while analysis of all patients found that only the number of months taking corticosteroids significantly affected BMD at all measured sites. However, the impact of the variables differed from site to site.

CONCLUSION

Our findings imply that most young adults with JA attain the same BMD as healthy subjects if the disease goes into remission, while young adults with active disease have increased risk for osteopenia and osteoporosis.

Effects of high-dose inhaled corticosteroids on bone metabolism in prepubertal children with asthma

We studied the effect of inhaled corticosteroids on the increase in bone mineral content in prepubertal children with asthma. Forty-eight asthmatic, prepubertal children receiving either inhaled beclomethasone dipropionate or budesonide were evaluated. Nine children of similar age not receiving inhaled steroids served as controls. The average age of corticosteroid-treated children was 7.8 +/- 2.4 years, and of control children, 8.4 +/- 2.1 years (NS). The average dose of inhaled corticosteroids in the treated children was 0.67 +/- 0.48 mg/m(2)/day, and they were followed over a 9-20-month period. Total bone mineral content (TBMC) was measured at baseline and after 9-20 months. A derived value for 12 months' TBMC was calculated, assuming that changes in TBMC were linear with the passage of time. The change in TBMC over a 12-month period was 264 +/- 68 mg for the corticosteroid-treated children and 330 +/- 84 mg for control children (P < 0.025). In a multiple regression analysis in which adjustments were made for the effects of age, height, and weight, the change in TBMC in corticosteroid-treated children was inversely related to the inhaled steroid dose/m(2)/day (P = 0.016). The increase in the lumbar vertebral bone mineral density in control children was also significantly greater than in the corticosteroid-treated children (P < 0.025). We conclude that inhaled steroids, at an average dose of 0.67 mg/m(2)/day, when used in the treatment of asthma reduce the acquisition of bone mineral in prepubertal children.

Juvenile idiopathic arthritis: a clinical overview

The chronic arthritides in childhood remain a poorly understood group of conditions. Their classification has been a source of much confusion over the years with differences in terminology between Europe and North America. A significant step forward in paediatric rheumatology has been the recent development of an internationally agreed classification system which uses the overall term juvenile idiopathic arthritis (JIA). The various subtypes of JIA and their clinical features are described, together with an overview of their differential diagnosis, complications and outcomes. An outline of current management strategies is given and potential future developments highlighted.

Assessment of bone mineral density in adults with a history of juvenile chronic arthritis: a cross-sectional long-term followup study

OBJECTIVE

To assess bone mineral density (BMD) and bone turnover in adults with a history of juvenile chronic arthritis (JCA) or persistent JCA, and to identify predictors of reduced BMD.

METHODS

Sixty-five white patients (mean age 32.2 years) with a history of JCA and 65 age-, sex-, height-, and weight-matched healthy control subjects participated in the study. Densitometry of the left hip and the lumbar spine was performed, and osteocalcin (bone formation marker) and crosslinks (bone resorption marker) were measured. In addition, bone-related clinical parameters were assessed in the JCA group.

RESULTS

BMD in the hip and lumbar spine was significantly lower in the JCA group than in the controls. Levels of osteocalcin and crosslinks were significantly increased in the JCA group. According to WHO definitions, significantly more subjects in the JCA group had "osteopenia" and "osteoporosis" than would be expected in a normal population sample. Active disease at the time of the study (1996-1997), baseline erosions evaluated in 1979, Steinbrocker functional class in 1996-1997, polyarticular course of JCA, and history of systemic steroid treatment for more than 1 year were significantly associated with reduced BMD. In linear regression analysis including both the JCA and control groups, presence of JCA proved to be the factor most strongly associated with reduced BMD, explaining approximately 20% of its variation.

CONCLUSION

Reduced BMD and evidence of increased bone turnover suggest that JCA patients may be at risk of developing premature osteoporosis and associated fractures later in life. The data are consistent with the concept that BMD in JCA is determined by many factors.

Bone mineral density in children with juvenile chronic arthritis

The aim of this study was to evaluate bone mineral density changes in patients with juvenile chronic arthritis (JCA) and to determine the most likely causes of osteoporosis in these patients. Eighteen (11 male, 7 female) patients suffering from JCA and 14 healthy controls (10 male, four female) were included in this study. The mean age of the patients and control groups were 11.0 +/- 3.2 and 10.9 +/- 2.9 years respectively. Disease activity was determined by clinical and laboratory evaluation and 'Articular Disease Severity Score' (ADSS). Bone mineral density (BMD) of the femoral neck and lumbar spine was measured by dual photon absorptiometry. BMD of the patients at the lumbar spine was significantly lower than the control group (p < 0.05). This difference was more marked in patients treated with steroids. Femoral neck BMD was also lower in the patient group but this difference was not statistically significant. There was a negative correlation between ADSS and BMD at the spine. In conclusion, trabecular bone loss is characteristic for osteoporosis in JCA. Our results indicate that steroid treatment and disease severity are important factors in the development of osteoporosis in JCA.

Dermatomyositis

Dermatomyositis is a rare inflammatory myopathy with characteristic skin manifestations and muscular weakness. The disease can be categorized as adult idiopathic, juvenile, or amyopathic dermatomyositis as well as that associated with a connective tissue disease or a malignancy. Immunologic factors are most likely involved in the pathogenesis of the disease; however, genetic and environmental issues may also play important roles. Treatment with immunosuppressive agents has proved successful in the majority of patients, although significant morbidity still occurs.

Bone turnover is reduced in children with juvenile rheumatoid arthritis

Juvenile Rheumatoid Arthritis (JRA) is frequently associated with osteoporosis. In order to determine if JRA osteoporosis is related to reduced formation or to increased bone resorption or both, serum levels of calcium (Ca), phosphorus (PO4), magnesium (Mg), alkaline phosphatase (ALP), parathormone (PTHi), 25-hydroxyvitamin D3 (25-OHD) and 1,25-dihydroxyvitamin D3 (1,25-(OH)2D), osteocalcin (OT), carboxyterminal propeptide (P-coll-1-c), and carboxyterminal telopeptide of type I collagen (ICTP) were evaluated in 47 JRA children, 33 with active disease and 14 in remission. The therapy consisted of nonsteroidal antiinflammatory (NSAIDs) drugs in pauciarticular subset, NSAIDs and Methotrexate (MTX) in polyarticular, NSAIDs and steroids in systemic onset. OT reflects bone formation, P-coll-1-c reflects collagen production and bone formation, ICTP, marker of collagen degradation in bone, indicates bone destruction. Serum levels of Ca, PO4, Mg, ALP, PTHi 25-OHD and 1,25-(OH)2D were comparable in JRA children and in controls. OT (8.7 +/- 3.7 ng/ml vs 9.6 +/- 5.1), P-coll-1-c (301.2 +/- 118.4 ng/ml vs 264.1 +/- 100.1) and ICTP (15.7 +/- 5.7 ng/ml vs 16.1 +/- 6.1) did not differ statistically in the whole group of JRA children vs controls. OT (8.0 +/- 3.5 vs 10.4 +/- 3.8) and ICTP (14.4 +/- 5.4 vs 18.8 +/- 5.4) were significantly lower in active than inactive group. In polyarticular and systemic onset OT and ICTP were significantly lower than in pauciarticular. No difference was found in active patients treated with steroids vs active patients treated with NSAIDS and NSAIDs plus MTX. The lower serum levels of OT and ICTP in active disease support the hypothesis that both bone formation and resorption are reduced in JRA bone turnover.

Effects of therapy with recombinant human growth hormone on insulin-like growth factor system components and serum levels of biochemical markers of bone formation in children after severe burn injury

Burn injury in children is associated with low bone formation and long-term bone loss. Because recombinant human GH (rHGH) may accelerate burn wound healing, and because rHGH increases bone formation and density in GH-deficient patients, we studied the short-term effects of rHGH on bone fomation, reflected by osteocalcin and type I procollagen propeptide levels in a randomized, double-blind, placebo-controlled study. Nineteen patients were enrolled and received either rHGH (0.2 mg/kg.day) or an equal volume of saline. Mean burn size and age were not different between the groups, and test substances were given from admission to time of wound healing (mean: 43 +/- 22 days). At wound healing, serum levels of insulin-like growth factor (IGF)-1 and IGF binding protein (IGFBP)-3 in the rHGH group rose to mean values of 229% and 187% of the respective means of the placebo group (P < 0.025). Serum osteocalcin concentrations remained below normal in both groups, and type I procollagen propeptide levels achieved a low normal level IGFBR-4 levels were twice that of normal on admission and doubled further at wound healing; IGFBP-5 levels were low on admission but rose to normal at wound healing. We conclude that large doses of rHGH were ineffective in improving disordered bone formation despite increasing serum IGF-1 and IGFBP-3. The rHGH-independent rise in serum levels of the inhibitory binding protein IGFBP-4 suggests a mechanism by which improved bone formation is prevented despite successful elevation of IGF-1 and IGFBP-3 in the burned child.

Predictors of total body bone mineral density in non-corticosteroid-treated prepubertal children with juvenile rheumatoid arthritis

OBJECTIVE

To determine the extent of significant osteopenia in prepubertal patients with juvenile rheumatoid arthritis (JRA) not treated with corticosteroids and to identify variables that are highly related to bone mineralization in this population.

METHODS

In a cross-sectional study, 48 JRA patients and 25 healthy control subjects ages 4.6-11.0 years were evaluated. Total body bone mineral density (TB BMD) was determined by Hologic dual energy x-ray absorptiometry. All patients were prepubertal (Tanner stage I or II) and had never taken corticosteroids. For comparison, JRA patients were divided into "low" TB BMD (Z score < or =-1) or "normal" TB BMD (Z score >-1).

RESULTS

The overall mean +/- SD TB BMD scores did not differ between the JRA subjects (0.75 +/- 0.06 gm/cm2) and controls (0.73 +/- 0.07 gm/cm2; P > 0.30). However, 29.2% of the JRA patients had low TB BMD, whereas only 16% would be expected to have low TB BMD based on the standard normal distribution (goodness of fit chi(2) = 4.84, P = 0.01). The mean Z score for the JRA patients with low TB BMD was -1.43, and for those with normal TB BMD, it was 0.32. The JRA subjects with low TB BMD were significantly younger, had more active articular disease, greater physical function limitation, higher erythrocyte sedimentation rate, higher joint count severity score, lower body mass index, lower lean body mass, less participation in organized sports, and more protein and vitamin D in their diet compared with JRA patients with normal TB BMD (all P < 0.05). Using logistic regression, a model including age at JRA onset, Juvenile Arthritis Functional Assessment Report (JAFAR) score, triceps skin-fold percentiles, percentage US recommended daily allowance for dietary magnesium intake, and serum 1,25-dihydroxyvitamin D levels was able to accurately segregate 79.6% of the JRA subjects into either the low or normal TB BMD groups (chi(2) = 20.5, P = 0.001).

CONCLUSION

This study demonstrated that in a mildly to moderately ill prepubertal JRA population that had never been exposed to corticosteroids, almost 30% had significantly low TB BMD. The patients with low TB BMD had more active and severe articular disease and greater physical function limitation. Disease-related parameters in JRA appear to exert a negative effect on bone mineralization even in prepubertal children, which can be demonstrated despite the exclusion of corticosteroid-treated patients.

Classification and treatment of the juvenile idiopathic inflammatory myopathies

This article reviews the current status of the classification and treatment of the juvenile idiopathic inflammatory myopathies. The intent of classification is to define homogeneous groups that share similar clinical features, disease courses, and responses to therapy. The classification scheme proposed includes clinicopathologic subsets, serologic subjects based on the presence of myositis-specific and myositis-associated autoantibodies, and environmental triggers of myositis. Juvenile dermatomyositis is the most common and widely recognized of these disorders. The second part reviews the history of treatment of juvenile dermatomyositis and discusses agents to consider for patients with refractory disease, unacceptable steroid toxicity, or poor prognostic factors.

Abnormalities in skeletal growth in children with juvenile rheumatoid arthritis

A review of the acquisition of peak skeletal mass in normal children and studies that have been reported for children with JRA lead to the following tentative conclusions: (1) The appendicular skeleton is predominantly the overall status of skeletal mineralization; (2) a failure to develop adequate bone mineralization is virtually universal in children with JRA and is characterized by a failure of bone formation. A failure to undergo the normal increase in bone mass during puberty is common in children with JRA and markedly decreases their potential to achieve an adequate peak skeletal mass; (3) the onset of accelerated skeletal maturation with puberty is a critical period of potential intervention in JRA. Conversely, therapeutic interventions later during adolescence offer less promise of reversal of inadequate bone mineralization; and (4) the most important therapeutic maneuver is likely to be control of the inflammation process, although there is hope, at present unsubstantiated, that supplemental dietary calcium and vitamin D, and normalization of physical activity, many lead to some "catch-up" mineralization.

Dysregulation of calcium homeostasis after severe burn injury in children: possible role of magnesium depletion

OBJECTIVE

To determine the cause and extent of hypocalcemia observed in children after severe burns.

DESIGN

We studied 10 children with burns covering 57% +/- 17% (SD) body surface area, ages 9.6 +/- 4.7 years, who were admitted consecutively during a 6-month period. Diet supplied a minimum of 2.7 gm/m2 of calcium, 0.3 gm/m2 of magnesium, and 2.2 gm/m2 phosphate. Blood specimens were obtained daily for 10 +/- 5 days for the following tests: (1) simultaneous analysis for ionized calcium, magnesium, and intact parathyroid hormone (group A); (2) two of these children, randomly selected, had serial 2-hour determinations on a single day (group B); (3) a modified Ellsworth-Howard test, consisting of a 10-minute infusion of synthetic parathyroid hormone 18 +/- 10 days post-burn and associated changes in urinary cyclic adenosine monophosphate excretion and renal threshold phosphate concentration (group C). Three of these children, when normomagnesemic, also received a standard magnesium infusion to determine magnesium retention (group D). Data were analyzed with chi-square, regression analysis, and non-parametric testing as appropriate.

RESULTS

All patients showed sustained hypocalcemia and hypomagnesemia; intact parathyroid hormone response was inappropriately low and response to synthetic parathyroid hormone infusion was blunted. Lowest ionized calcium levels were associated with hypomagnesemia.

CONCLUSION

Hypoparathyroidism and blunted renal response to parathyroid hormone suggest that magnesium depletion may contribute to their pathogenesis. Magnesium repletion and monitoring are recommended.

Long-term effects of bisphosphonates on the growing skeleton. Studies of young patients with severe osteoporosis

Osteoporosis in children and adolescents is relatively uncommon and usually secondary to identifiable causal factors. There are no generally accepted therapies for patients with no treatable underlying cause of disease. Any treatment of young patients with bone-acting compounds should be not only effective but also devoid of adverse effects on bone growth and remodeling. For many years we have been studying the effects of bisphosphonates-an effective treatment of postmenopausal osteoporosis-on the growing skeleton. We review here our experience in the treatment of young patients with osteoporosis with special emphasis on issues of skeletal safety and effectiveness, and we discuss the available literature data. We studied 12 patients aged between 10.7 and 17.2 years with symptomatic osteoporosis and multiple fractures treated with the bisphosphonates pamidronate or olpadronate for periods between 2 and 8 years continuously. Linear growth continued normally on treatment; there was even a catch-up growth in prepubertal patients, and there was no excessive suppression of bone remodeling, assessed biochemically. Bone biopsies obtained at various stages during treatment showed bone of normal lamellar structure without mineralization defects. There was an increase in calcium balance, already evident within 10 days, the level of which was maintained for at least 3 years of treatment. This was associated with progressive increases in bone mineral density along a different slope from that of healthy peers as well as correction of vertebral deformities on X-rays in patients given bisphosphonates before puberty. Treatment was well tolerated and clinical improvement was remarkable. Our studies, supported by literature data, strongly suggest that bisphosphonate therapy can be beneficial to young patients with osteoporosis for whom no other options are currently available, and justify planning controlled studies in more common conditions for which no treatment is currently available, such as osteogenesis imperfecta.

Juvenile rheumatoid arthritis. Effects of disease activity and recombinant human growth hormone on insulin-like growth factor 1, insulin-like growth factor binding proteins 1 and 3, and osteocalcin

OBJECTIVE

To investigate possible mechanisms of growth impairment in children with juvenile rheumatoid arthritis (JRA).

METHODS

Eighteen prepubertal children with JRA and growth retardation received recombinant human growth hormone (rHuGH) for 1 year. Growth hormone profiles over 24 hours were obtained before treatment in 12 patients; the levels did not differ from those in "short normal" children. Levels of insulin-like growth factor 1 (IGF-1), IGF binding proteins (IGFBPs) 1 and 3, insulin, osteocalcin, and C-reactive protein (CRP), as well as the erythrocyte sedimentation rate were measured serially. Pretreatment levels were compared with control levels.

RESULTS

In JRA patients, IGF-1, IGFBP-3, and osteocalcin levels were significantly lower and insulin levels significantly higher than those in controls, but there was no significant difference in the level of IGFBP-1. With rHuGH treatment, height velocity and mean levels of IGF-1, osteocalcin, and insulin increased significantly, while mean levels of IGFBP-1 fell significantly. Levels of IGFBP-3 correlated with those of IGF-1. The height velocity correlated positively with IGF-1 and osteocalcin, and negatively with IGFBP-1. Levels of IGFBP-1 were inversely related to those of insulin and IGF-1. There was a significant negative correlation between the CRP and height velocity, IGF-1 level, and osteocalcin level.

CONCLUSION

IGF-1 production is impaired in children with active JRA. Treatment with a therapeutic dose of rHuGH can rectify the IGF-1 deficiency within 4 days, but its effect is adversely influenced by the acute-phase response, as reflected by an elevated CRP level.

Constitutively activated receptors for parathyroid hormone and parathyroid hormone-related peptide in Jansen's metaphyseal chondrodysplasia

BACKGROUND

An activating mutation of the receptor for parathyroid hormone (PTH) and parathyroid hormone-related peptide (PTHrP) was recently found in a patient with Jansens's metaphyseal chondrodysplasia, a rare form of short-limbed dwarfism associated with hypercalcemia and normal or low serum concentrations of the two hormones. To investigate this and other activating mutations and to refine the classification of this unusual disorder, we analyzed genomic DNA from six additional patients with Jansen's disease.

METHODS

Exons encoding the PTH-PTHrP receptor were amplified by the polymerase chain reaction (PCR), and the products were analyzed by gel electrophoresis or direct nucleotide-sequence analysis. Nucleotide changes were confirmed by restriction-enzyme digestion of genomic DNA or the PCR products.

RESULTS

The previously reported mutation, which changes a histidine at position 223 to arginine (H223R), was found in genomic DNA from three of the six patients but not in DNA from their healthy relatives or 45 unrelated normal subjects. A novel missense mutation that changes a threonine in the receptor's sixth membrane-spanning region to proline (T410P) was identified in another patient but not in 62 normal subjects. In two patients with radiologic evidence of Jansen's metaphyseal chondrodysplasia but less severe hypercalcemia, no receptor mutations were detected. In COS-7 cels expressing PTH-PTHrP receptors with the T410P or H223R mutation, basal cyclic AMP accumulation was four to six times higher than in cells expressing wild-type receptors.

CONCLUSIONS

The expression of constitutively active PTH-PTHrp receptors in kidney, bone, and growth-plate chondrocytes provides a plausible genetic explanation for mineral-ion abnormalities and metaphyseal changes in patients with Jansen's disease.

Latent hypoparathyroidism in children with conotruncal cardiac defects

BACKGROUND

DiGeorge anomaly is characterized by hypoplasia or atresia of the thymus and parathyroid glands resulting in T cell-mediated deficiency, hypocalcemic hypoparathyroidism, and conotruncal cardiac defects. It usually is associated with deletions of chromosomal region 22q11. We hypothesized that the stimulated (secretory reserve) but not the constitutive secretion of parathyroid hormone would be reduced in normocalcemic children with conotruncal cardiac defects but no overt immune deficiency and would be related to the presence of a deletion in the DiGeorge chromosomal region of 22q11.

METHODS AND RESULTS

Blood-ionized calcium and serum-intact parathyroid hormone were measured at baseline and seven more times during hypocalcemia induced during cardiopulmonary bypass in 22 patients and 10 control subjects with an atrial septal defect. Chromosomal deletions were detected by fluorescent in situ hybridization and DNA dosage analysis. There were no differences in basal calcium and parathyroid hormone levels between patients and control subjects. All had increased parathyroid hormone in response to hypocalcemia; despite lower calcium levels, parathyroid hormone levels were lower in patients. The parathyroid hormone secretory reserve in 14 of 22 patients was reduced compared with control subjects; 4 of the 14 had deletions.

CONCLUSIONS

A significant number of children with conotruncal cardiac defects have normocalcemia and a normal constitutive level of parathyroid hormone but deficient parathyroid hormone secretory reserve; about 30% also have 22q11 deletions. Such children may be at risk for the later development of hypocalcemic hypoparathyroidism.

Bone mineralization and bone mineral metabolism in children with juvenile rheumatoid arthritis

OBJECTIVE

To identify mechanisms of the osteopenia associated with juvenile rheumatoid arthritis (JRA) by determining parameters of bone mineralization, and bone mineral content and density (BMC and BMD), in children with JRA.

METHODS

BMC and BMD were measured by dual x-ray absorptiometry in 41 children with JRA and 62 healthy children. Serum samples were analyzed for concentrations of minerals, vitamin D, parathyroid hormone, osteocalcin, bone-specific alkaline phosphatase (BAP), procollagen I carboxy-terminal propeptide, and tartrate-resistant acid phosphatase (TRAP), and urinary excretion of deoxypyridinoline crosslinks and calcium.

RESULTS

BMD was decreased in all sites in JRA patients. BMD, corrected for age, height, weight, and bone area, was decreased at cortical bone sites (1/3 radius, upper and lower extremities, and whole body). Low concentrations of osteocalcin and BAP suggested reduced bone formation, and low TRAP levels suggested decreased resorption. Clinical scales of disease severity were negatively correlated with measures of bone mass. Laboratory markers of disease severity were highly correlated with decreases in markers of bone formation, but not with those of resorption. Although laboratory findings were similar for children with oligoarticular and polyarticular disease, differences in bone mass were greater in children with polyarticular disease.

CONCLUSION

These data suggest an association between decreased bone mineralization in JRA and low bone formation that is related to disease severity. Efforts to stimulate bone formation, therefore, need to be considered clinically in prepubertal children with active JRA.