Weight-bearing physical activity, calcium intake, systemic glucocorticoids, chronic inflammation, and body constitution as determinants of lumbar and femoral bone mineral in juvenile chronic arthritis

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.

The impact of underlying disease on fracture risk and bone mineral density in children with rheumatic disorders: A review of current literature

Childhood rheumatic diseases are associated with negative impacts on the skeleton, related to both the underlying illness and complications of therapy. The effects of medications like corticosteroids are well recognized, leading to reductions in bone mineral density and bone strength and concomitant increases in bone fragility and fracture risk. The impact of factors directly attributable to the underlying disease is not as well recognized. In this article, we review relevant literature to identify data which can contribute to an understanding of the impact of childhood rheumatic disease on the skeleton. We conclude that childhood rheumatic diseases are associated with reductions in bone mineral density and increased risk of vertebral and non-vertebral fractures. These data are strongest for juvenile arthritis, while conclusions are more limited for other rheumatic illnesses, like juvenile systemic lupus erythematosus or juvenile dermatomyositis, due to small numbers of patients studied. Finally, we make recommendations for areas in need of further research. These include the need for long-term longitudinal studies and for data to be collected in patients who have not been treated with corticosteroids.

Bone mass and quality in patients with juvenile idiopathic arthritis: longitudinal evaluation of bone-mass determinants by using dual-energy x-ray absorptiometry, peripheral quantitative computed tomography, and quantitative ultrasonography

Introduction

Our objective was to evaluate longitudinally the main bone-mass and quality predictors in young juvenile idiopathic arthritis (JIA) patients by using lumbar spine dual-energy X-ray absorptiometry (DXA) scan, radius peripheral quantitative computed tomography (pQCT), and phalangeal quantitative ultrasonography (QUS) at the same time.

Methods

In total, 245 patients (172 females, 73 males; median age, 15.6 years: 148 oligoarticular, 55 polyarticular, 20 systemic, and 22 enthesitis-related-arthritis (ERA) onset) entered the study. Of these, 166 patients were evaluated longitudinally. Data were compared with two age- and sex-matched control groups.

Results

In comparison with controls, JIA patients, but not with ERA, had a reduced spine bone-mineral apparent density (BMAD) standard deviation score (P < 0.001) and musculoskeletal deficits, with significantly lower levels of trabecular bone mineral density (TrabBMD) (P < 0.0001), muscle cross-sectional area (CSA) (P < 0.005), and density-weighted polar section modulus (SSIp) (P < 0.05). In contrast, JIA showed fat CSA significantly higher than controls (P < 0.0001). Finally, JIA patients had a significant reduced amplitude-dependent speed of sound (AD-SoS) (P < 0.001), and QUS z score (P < 0.005).

Longitudinally, we did not find any difference in all JIA patients in comparison with baseline, except for the SSIp value that normalized. Analyzing the treatments, a significant negative correlation among spine BMAD values, TrabBMD, AD-SoS, and systemic and/or intraarticular corticosteroids, and a positive correlation among TNF-α-blocking agents and spine BMAD, TrabBMD, and AD-SoS were observed.

Conclusions

JIA patients have a low bone mass that, after a first increase due to the therapy, does not reach the normal condition over time. The pronounced bone deficits in JIA are greater than would be expected because of reduction in muscle cross-sectional area. Thus, bone alterations in JIA likely represent a mixed defect of bone accrual and lower muscle forces.

Genetic polymorphisms of collagen type I α1 chain (COL1A1) gene increase the frequency of low bone mineral density in the subgroup of children with juvenile idiopathic arthritis

BACKGROUND

Collagen type I is one of the key proteins involved in the maturation, development and mineralization of bone. Genetic polymorphisms of collagen type I alpha-1 chain (COL1A1) gene are associated with low bone mineral density and higher risk of fractures in adults and children. We hypothesize that the polymorphic alleles and genotypes of COL1A1 gene influence bone mineralization and metabolism in children with juvenile idiopathic arthritis (JIA).

METHODS

We recruited 196 children with JIA in our study. Bone mineral density (BMD) was measured by lumbar spine dual-energy X-ray absorptiometry. Osteocalcin, Ca, Ca2+ and inorganic phosphate (Pi) were utilized for the assessment of bone metabolism. Molecular testing: Sp1 (rs1800012) and -1997G/T (rs1107946) polymorphisms of COL1A1 gene were detected RFLP.

RESULTS

No differences in genotype, allele and haplotype distribution of COL1A1 were detected among children with normal and low BMD (LBMD; <-2 standard deviation). The presence of GG genotype of Sp1 increased the incidence of LBMD in Tanner II to III children (odds ratio (OR) = 9.7 [95% confidence interval (CI), 1.2; 81.7], p = 0.02) as well as GG genotype of -1997G/T increased the frequency of LBMD in Tanner IV to V children (OR = 4.5 [95% CI, 0.9; 22.0], p = 0.048). Tanner I children with -1997GG genotype had lower Ca2+ and osteocalcin and higher Pi compared with carriers of -1997Т allele. Tanner IV to V children with -1997GG genotype had lower BMD and BMD-Z score than carriers of -1997Т.

CONCLUSIONS

The evaluation of the biologic effects of the GG Sp1 and GG of -1997G/T polymorphism of COL1A1 has shown negative effect on BMD and mineral turnover related to pubertal stage.

Prevalence of vertebral compression fractures and associated factors in children and adolescents with severe juvenile idiopathic arthritis

OBJECTIVE

Vertebral fractures occur in patients with juvenile idiopathic arthritis (JIA), but data on their frequency and causes are scarce. Our cross-sectional study evaluated prevalence of compression fractures and associated factors in a high-risk pediatric population with severe JIA.

METHODS

Children and adolescents with a history of treatment-resistant polyarticular-course JIA for ≥ 5 years or systemic arthritis for ≥ 3 years were recruited. Clinical examination, dietary recall, laboratory measurements, bone mineral density (BMD) measurement by dual-energy X-ray absorptiometry, and spinal radiography were performed.

RESULTS

Our study included 50 patients (41 girls), of whom 6 (12%) had systemic arthritis, with a median age of 14.8 years (range 7.0-18.7 yrs) and median disease duration of 10.2 years (range 3.9-16.8 years). Ninety-four percent had used systemic glucocorticoids (GC); the median total duration of GC treatment was 7.1 years (range 0-15.5 yrs). The median weight-adjusted cumulative GC dose for the preceding 3 years was 72 mg/kg (range 0-911 mg/kg). The median bone age-corrected lumbar spine and whole-body areal BMD Z-scores were -0.8 and -1.0, respectively. Twenty-two percent had vertebral fractures, mostly thoracic. Compression fractures were associated with high disease activity, high body mass index (BMI), and high recent cumulative GC dose, but not with disease duration or BMD. Thirty percent had sustained at least 1 peripheral low energy fracture. Twenty-six percent were deemed to have significantly compromised bone health.

CONCLUSION

Severe JIA is associated with a significant risk of vertebral compression fractures. Associated factors include high disease activity, high BMI, and high recent GC exposure. Further studies are needed to establish optimal prevention and treatment guidelines.

Efficacy and harms of nasal calcitonin in improving bone density in young patients with inflammatory bowel disease: a randomized, placebo-controlled, double-blind trial

OBJECTIVES

There are very few published studies of agents having the potential to improve bone health in children with inflammatory bowel disease (IBD). The objective of this study was to establish the efficacy and safety of intranasal calcitonin in improving bone mineral density (BMD) in young patients with IBD and to define additional factors that impact bone mineral accrual.

METHODS

We conducted a randomized, placebo-controlled, double-blind clinical trial in 63 participants, ages 8-21 years, with a spinal BMD Z-score ≤ -1.0 s.d. measured by dual energy X-ray absorptiometry. Subjects were randomized to 200 IU intranasal calcitonin (n=31) or placebo (n=32) daily. All received age-appropriate calcium and vitamin D supplementation. Subsequent BMD measurements were obtained at 9 and 18 months.

RESULTS

Intranasal calcitonin was well tolerated. Adverse event frequency was similar in both treatment groups, and such events were primarily minor, reversible, and limited to the upper respiratory tract. The BMD Z-score change documented at screening and 9 months and screening and 18 months did not differ between the two therapeutic arms. In participants with Crohn's disease, the spinal BMD Z-score improved between screening and 9 months (change in spine BMD Z-score (ΔZSBMD)(9-0)) in the calcitonin group (ΔZSBMD(9-0)(calcitonin)=0.21 (0.37), ΔZSBMD(9-0)(placebo)=-0.15 (0.5), P=0.02); however, this was only a secondary subgroup analysis. Bone mineral accrual rate during the trial did not lead to normalization of BMD Z-score in this cohort. Factors favoring higher bone mineral accrual rate were lower baseline BMD and higher baseline body mass index Z-score, improvement in height Z-score, higher serum albumin, hematocrit and iron concentration, and more hours of weekly weight-bearing activity. Factors associated with lower bone mineral accrual rate were more severe disease-as indicated by elevated inflammatory markers, need for surgery, hospitalization, and the use of immunomodulators-and higher daily caffeine intake.

CONCLUSIONS

Intranasal calcitonin is well tolerated but does not offer a long-term advantage in youth with IBD and decreased BMD. Bone mineral accrual rate remains compromised in youth with IBD and low BMD raising concerns for long-term bone health outcomes. Improvement in nutritional status, catch-up linear growth, control of inflammation, increase in weight-bearing activity, and lower daily caffeine intake may be helpful in restoring bone density in children with IBD and low BMD.

Bone health in adult men and women with a history of juvenile idiopathic arthritis

OBJECTIVE

Our aim was to determine areal bone mineral density (BMD(a)) and disease-related factors linked with BMD(a) in adults with a history of juvenile idiopathic arthritis (JIA).

METHODS

Men and women with a history of JIA attending a young adult rheumatology clinic in Newcastle, UK, underwent dual energy x-ray absorptiometry (DEXA) of the lumbar spine and total hip. Information was obtained about disease duration and subtype, previous treatment including corticosteroid and methotrexate therapy, and large-joint replacement. Subjects completed the modified Health Assessment Questionnaire (HAQ). Blood was taken for assessment of C-reactive protein, erythrocyte sedimentation rate, and rheumatoid factor (RF).

RESULTS

Seventy-one women and 16 men, mean age 28.7 and 31.4 years, and mean disease duration 20.6 and 24.0 years, respectively, were studied. Mean BMD(a) was 0.982 (Z-score = -0.328; 95% CI -0.657, 0.001) and 1.028 g/cm(2) (Z-score = -0.251; 95% CI -1.266, 0.764) in women and men, respectively, at the spine and 0.817 (Z-score = -0.542; 95% CI -0.975, -0.109) and 0.857 g/cm(2) (Z-score = -0.176; 95% CI -2.323, 1.971) at the hip. After adjusting for age and sex, increasing HAQ score was associated with both lower spine BMD(a) and hip BMD(a). Compared with patients with oligoarticular disease, those with enthesitis-related arthritis had higher BMD(a) at the spine, while those with extended oligoarticular and polyarticular RF-negative disease had lower hip BMD(a). Oral corticosteroids and the presence of a large-joint replacement were associated with lower BMD(a) at both the spine and hip.

CONCLUSION

There was a trend toward low BMD(a) in women with a history of JIA. These patients may be at risk of the complications of osteoporosis including fragility fractures and should be considered for targeted preventive measures.

Biologic therapy and its effect on skeletal development in children with chronic inflammation

Chronic inflammatory conditions in children such as juvenile idiopathic arthritis, inflammatory bowel disease, cystic fibrosis and systemic lupus erythematosus can cause reduced linear growth, final height and bone mass. There are many mechanisms leading to these skeletal alterations but inflammation itself is considered to play an important role. Biologic therapy is being used increasingly for the treatment of chronic inflammatory conditions and may also be effective in improving growth and skeletal development. The main aim of this article is to summarize the effects of inflammation on growth and skeletal development and evaluate the effects of biologic therapy on growth and skeletal development in children with chronic inflammatory conditions.

Cross-sectional and Longitudinal Evaluation of Bone Mass in Children and Young Adults with Juvenile Idiopathic Arthritis: The Role of Bone Mass Determinants in a Large Cohort of Patients

Objective.

To assess the prevalence of reduced spine bone mineral apparent density (BMAD), and to identify the main predictors of reduced spine BMAD in a cross-sectional and longitudinal evaluation of the same large cohort of patients with juvenile idiopathic arthritis (JIA). There are few prospective data on bone mass evaluation in a large number of patients with JIA, and with enthesitis-related arthritis onset.

Methods.

Two hundred nineteen patients with JIA (median age 8.7 yrs, range 6.1–13.1 yrs; 104 oligoarticular JIA, 61 polyarticular, 20 systemic, and 34 enthesitis-related arthritis onset) were retrospectively evaluated. A dual-energy x-ray absorptiometry (DEXA) scan at the lumbar spine was performed in all subjects. Of these, 89 consecutive patients were followed up randomly and longitudinally with a second and a third DEXA evaluation. The data obtained were compared with 80 age-matched and sex-matched healthy subjects.

Results.

At the first DEXA, patients with JIA showed a reduced spine BMAD standard deviation score (SDS) in comparison to controls (p < 0.001). These results were confirmed when the subjects were divided into JIA subtypes (p < 0.005) with the exception of enthesitis-related arthritis onset. Spine BMAD SDS significantly correlated with JIA onset type (p < 0.01), age at JIA onset (p < 0.005), and flares (p = 0.008). The longitudinal evaluation showed that spine BMAD SDS did not significantly improve at the followup in comparison to controls, in all subsets with JIA except for systemic onset (p < 0.05). Spine BMAD correlated with sex (p < 0.01), systemic corticosteroid exposure (p < 0.01), the number of intraarticular corticosteroid injections (p < 0.01), the interval from last steroid injection (p < 0.05), erythrocyte sedimentation rate (p < 0.005), and C-reactive protein levels (p < 0.005).

Conclusion.

Patients with JIA have a low bone mass and, after a first increase due to therapy, do not reach a healthy condition over time despite our current more effective drugs. These patients have a high risk of osteoporosis in early adulthood. To reduce the risk and improve the bone mass, close monitoring of bone mineral density, better control of disease activity, physical activity, and intake of calcium and vitamin D are recommended. In patients with osteoporosis, therapeutic approaches including bisphosphonates should be considered.

Prevalent vertebral fractures among children initiating glucocorticoid therapy for the treatment of rheumatic disorders

OBJECTIVE

Vertebral fractures are an under-recognized problem in children with inflammatory disorders. We studied spine health among 134 children (87 girls) with rheumatic conditions (median age 10 years) within 30 days of initiating glucocorticoid therapy.

METHODS

Children were categorized as follows: juvenile dermatomyositis (n = 30), juvenile idiopathic arthritis (n = 28), systemic lupus erythematosus and related conditions (n = 26), systemic arthritis (n = 22), systemic vasculitis (n = 16), and other conditions (n = 12). Thoracolumbar spine radiograph and dual x-ray absorptiometry for lumbar spine (L-spine) areal bone mineral density (BMD) were performed within 30 days of glucocorticoid initiation. Genant semiquantitative grading was used for vertebral morphometry. Second metacarpal morphometry was carried out on a hand radiograph. Clinical factors including disease and physical activity, calcium and vitamin D intake, cumulative glucocorticoid dose, underlying diagnosis, L-spine BMD Z score, and back pain were analyzed for association with vertebral fracture.

RESULTS

Thirteen vertebral fractures were noted in 9 children (7%). Of these, 6 patients had a single vertebral fracture and 3 had 2-3 fractures. Fractures were clustered in the mid-thoracic region (69%). Three vertebral fractures (23%) were moderate (grade 2); the others were mild (grade 1). For the entire cohort, mean +/- SD L-spine BMD Z score was significantly different from zero (-0.55 +/- 1.2, P < 0.001) despite a mean height Z score that was similar to the healthy average (0.02 +/- 1.0, P = 0.825). Back pain was highly associated with increased odds for fracture (odds ratio 10.6 [95% confidence interval 2.1-53.8], P = 0.004).

CONCLUSION

In pediatric rheumatic conditions, vertebral fractures can be present prior to prolonged glucocorticoid exposure.

Prevalence of vertebral fractures in children with chronic rheumatic diseases at risk for osteopenia

OBJECTIVES

To determine the prevalence of and the risk factors for vertebral fractures in a cohort of children with chronic rheumatic diseases considered at risk for osteopenia.

STUDY DESIGN

We conducted a cross-sectional study of patients with chronic rheumatic diseases at the Montreal Children's Hospital.

RESULTS

Of the 90 study participants (22 boys, 68 girls), 10 boys and 7 girls (19%) were found to have vertebral fractures. These 17 children had a total of 50 fractures, an average of 2.9 per affected child. Fractures in the upper thoracic region (T5-8) accounted for 55%. Only 56% of all fractures were symptomatic. With multivariate regression, we identified male sex (P < .01), body mass index z-score (P < .02), and cumulative glucocorticoid dose (P < .01) as significant predictors of the number of vertebral fractures.

CONCLUSIONS

Our study examined the prevalence of vertebral fractures in a high-risk pediatric population. Nineteen percent of our cohort had vertebral fractures. Significant risk factors for the development of vertebral fractures include male sex and cumulative glucocorticoid dose. Better understanding of the extent of the problem in this population will allow us to further refine screening guidelines and treatment in these patients.

Chronic pediatric inflammatory diseases: effects on bone

In children, chronic inflammatory diseases present a significant challenge to long-term skeletal health. These conditions are often associated with poor appetite and suboptimal overall nutrition, altered nutrient utilization, delayed puberty, inactivity, and reduced muscle mass, all of which can alter bone metabolism. In addition, bone cell activity is susceptible to the effects of the immune response that characterizes these diseases. Moreover, drugs used to treat these maladies, notably glucocorticoids, may have negative effects on bone formation and on linear growth in developing children. As a result, predicted peak bone mass may not be achieved, and fracture risk may be increased in the short term or in the future. Studies using primarily dual energy X-ray absorptiometry have documented that deficits in bone mass are common in these diseases. However, there are wide variations in the prevalence of low bone mass, largely due to differences in the characteristics of each study population. Recent studies provide insight into the pathogenesis of decreased bone mass in these conditions. In this paper we will provide an overview of the effects of chronic inflammatory conditions on bone mass in children. We will also present relevant data from adult patients, when pediatric data are scant or not available.

Bone mineral apparent density in juvenile dermatomyositis: the role of lean body mass and glucocorticoid use

OBJECTIVE

To analyse bone mineral density (BMD) in juvenile dermatomyositis (JDM) and its possible association with body composition, disease activity, duration of disease, glucocorticoid (GC) use, and biochemical bone parameters, including osteoprotegerin (OPG) and receptor activator of nuclear factor kappaB (RANKL).

METHODS

Twenty girls with JDM and 20 controls matched for gender and age were selected. Body composition and BMD were analysed by dual-energy X-ray absorptiometry (DXA) and bone mineral apparent density (BMAD) was calculated. Duration of disease, cumulative GC, and GC pulse therapy use were determined from medical records. Disease activity and muscle strength were measured by the Disease Activity Score (DAS), the Childhood Myositis Assessment Scale (CMAS), and the Manual Muscle Test (MMT). Inflammatory and bone metabolism parameters were also analysed. OPG and RANKL were measured in patients and controls using an enzyme-linked immunosorbent assay (ELISA).

RESULTS

A lower BMAD in the femoral neck (p<0.001), total femur (p<0.001), and whole body (p = 0.005) was observed in JDM patients compared to controls. Body composition analysis showed a lower lean mass in JDM compared to controls (p = 0.015), but no difference was observed with regard to fat mass. A trend of lower serum calcium was observed in JDM (p = 0.05), whereas all other parameters analysed, including OPG and RANKL, were similar. Multiple linear regression analysis revealed that, in JDM, lean mass (p<0.01) and GC pulse therapy use (p<0.05) were independent factors for BMAD in the hip region.

CONCLUSIONS

This study has identified low lean mass and GC pulse therapy use as the major factors for low hip BMAD in JDM patients.

[Diagnosis, prophylaxis and therapy of osteoporosis in juvenile idiopathic arthritis: consensus statement of the German Association for Pediatric Rheumatology]

In all subgroups of juvenile idiopathic arthritis (JIA), a pathologic loss of bone or the lack of increase in bone mass has been described in a high percentage of cases, even with new therapeutic approaches. The decrease in bone mass is correlated with the duration of active disease and the number of affected joints (cytokines, inactivity). In several studies, muscle mass was the strongest predictor of bone mass. A standardized diagnostic approach to the musculoskeletal system including measures of prophylaxis and therapy therefore seems to be mandatory for all children with JIA who do not achieve rapid remission. In this review, the diagnostic and therapeutic options are described and summarized in an algorithm.

Bisphosphonate therapy for children and adolescents with secondary osteoporosis

BACKGROUND

Children with chronic illnesses are at increased risk for reductions in bone strength and subsequent fractures (osteoporosis), either due to the impact of the underlying condition on skeletal development or due to the osteotoxic effect of medications (e.g., glucocorticoids) used to treat the chronic illness. Bisphosphonates are being administered with increasing frequency to children with secondary osteoporosis; however, the efficacy and harm of these agents remains unclear.

OBJECTIVES

To examine the efficacy and harm of bisphosphonate therapy in the treatment and prevention of secondary osteoporosis in children and adolescents.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (Issue 4, 2006), MEDLINE, EMBASE, CINAHL and ISI Web of Science (inception-December 2006). Further literature was identified through expert contact, key author searches, scanning reference lists of included studies, and contacting bisphosphonate manufacturers.

SELECTION CRITERIA

Randomized, quasi-randomized, controlled clinical trials, cohort, and case controls of bisphosphonate(s) in children 0-18 years of age with at least one low-trauma fracture event or reductions in bone mineral density in the context of secondary osteoporosis.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data and assessed quality. Case series were used for supplemental harms-related data.

MAIN RESULTS

Six RCTs, two CCTs, and one prospective cohort (n=281 children) were included and classified into osteoporosis due to: 1) neuromuscular conditions (one RCT) and 2) chronic illness (five RCTs, two CCTs, one cohort). Bisphosphonates examined were oral alendronate, clodronate, and intravenous (IV) pamidronate. Study quality varied. Harms data from 23 case series (n=241 children) were used. Heterogeneity precluded statistically combining the results. Percent change or Z-score change in lumbar spine areal BMD from baseline were consistently reported. Two studies carried out between-group analyses; one showed no significant difference (using oral alendronate in anorexia nervosa) while the other demonstrated a treatment effect on lumbar spine with IV pamidronate in burn patients. Frequently reported harms included the acute phase reaction, followed by gastrointestinal complaints, and bone/muscle pain.

AUTHORS' CONCLUSIONS

The results justify further evaluation of bisphosphonates among children with secondary osteoporosis. However, the evidence does not support bisphosphonates as standard therapy. Short-term (3 years or less) bisphosphonate use appears to be well-tolerated. An accepted criterion for osteoporosis in children, a standardized approach to BMD reporting, and examining functional bone health outcomes (e.g., fracture rates) will allow for appropriate comparisons across studies.

Osteoporosis in juvenile idiopathic arthritis--a practical approach to diagnosis and therapy

In all subgroups of juvenile idiopathic arthritis, a decrease in bone mass has been described in a high percentage of children. Recently, new pathogenetic concepts have identified muscle mass as the strongest predictor of bone mass and bone is now recognized as part of the musculoskeletal system. In addition, the sophisticated use of bone densitometry in pediatrics, including new measurement techniques, has provided the tools for a reliable assessment. A standardized diagnostic approach to the musculoskeletal system, including prophylaxis and therapy, is, therefore, mandatory in all children with JIA who do not achieve rapid remission. In this review, diagnostic and therapeutic options are being described and possibilities to incorporate them into clinical practice are suggested.

Prevalence and etiology of low bone mineral density in juvenile systemic lupus erythematosus

OBJECTIVE

Studies of adults with systemic lupus erythematosus (SLE) have frequently demonstrated the presence of decreased bone mineral density (BMD). However, there have been few investigations in pediatric patients to date. This study was undertaken to determine the prevalence of low BMD in patients with juvenile SLE and to identify associated risk factors.

METHODS

We studied 64 consecutive patients with juvenile SLE in whom routine dual x-ray absorptiometry (DXA) scanning was performed. Lumbar spine osteopenia was defined as a BMD Z score of < -1 and > or = -2.5, and osteoporosis as a BMD Z score of < -2.5. Decreased hip BMD was defined as a value of < 80%. Data on disease activity, quality of life, disease-related damage, sex, ethnicity, body mass index, age at diagnosis, age at DXA, medication use and duration, clinical features, and puberty status were collected at the time of DXA.

RESULTS

Lumbar spine osteopenia was seen in 24 patients (37.5%) and osteoporosis in 13 (20.3%). Decreased hip BMD was present in 12 patients (18.8%). By univariate analysis, osteopenia was significantly correlated with age, disease duration, duration of corticosteroid use, cumulative corticosteroid dose, azathioprine use, cyclophosphamide use, lupus nephritis, and damage. Two additional variables, mycophenolate mofetil use and class III-IV nephritis, were associated with osteoporosis. Abnormal hip BMD was associated with disease duration, duration of corticosteroid use, and cumulative corticosteroid dose. By multivariate analysis, only disease duration remained in the model for osteoporosis and abnormal hip BMD, while cumulative corticosteroid dose was the variable associated with osteopenia.

CONCLUSION

These results indicate that osteopenia and osteoporosis are common in juvenile SLE and are associated more closely with increased disease duration than with cumulative corticosteroid dose.

Can exercise influence low bone mineral density in children with juvenile rheumatoid arthritis?

PURPOSE

Low bone mineral density (BMD) is a common secondary condition associated with juvenile idiopathic arthritis (JIA). The purpose of this review was evaluate the literature pertinent to designing an effective, safe weight-bearing exercise program to reduce the risk of low BMD in children with JIA.

SUMMARY OF KEY POINTS

Thirty-seven articles on the risk of low BMD and children with JIA, weight-bearing interventions to improve BMD in healthy children, or safety and efficacy of exercise interventions with children with JIA were critiqued on the basis of their design. Three highly rated studies confirmed the multifactorial nature of low BMD in children with JIA, two highly rated studies support the efficacy of weight-bearing interventions for increasing BMD in children who are healthy, and one moderately rated study demonstrated the safety of low impact exercise by children with JIA.

STATEMENT OF CONCLUSIONS AND RECOMMENDATIONS FOR CLINICAL PRACTICE

Weight-bearing activities should be included in exercise programs for individuals with JIA, although more research is needed to determine the amount, duration, and frequency of weight-bearing activity needed to reduce the risk for low BMD.

Systematic review of effectiveness of bisphosphonates in treatment of low bone mineral density and fragility fractures in juvenile idiopathic arthritis

AIMS

To evaluate the currently available evidence for the effectiveness of bisphosphonates in children with low bone mineral density (BMD) and fragility fractures associated with juvenile idiopathic arthritis (JIA), and the safety of bisphosphonates in JIA and other conditions.

METHODS

Literature databases were searched using a structured search strategy. The effectiveness review included any studies of children with JIA treated with bisphosphonates. The safety review also included studies of osteogenesis imperfecta. Quantitative data analysis was not undertaken because of the heterogeneity of the studies; findings were summarised using tables and narrative synthesis.

RESULTS

Ninety four studies were identified. Sixteen studies (78 JIA children) were included in the effectiveness review: one randomised controlled trial, three controlled cohort studies, 11 case series, and one case report. At baseline, children had low BMD below the expected values for age and sex matched children. In all studies, treatment with bisphosphonates increased BMD compared with baseline: the mean percentage increase in spine BMD ranged from 4.5% to 19.1%. Overall, studies were heterogeneous and of variable quality. A total of 59 papers were included in the safety review; treatment durations were up to three years. The most common side effect was a flu-like reaction with intravenous treatment. This occurred during the first infusion and was transient; the symptoms were managed with paracetamol and did not occur during subsequent cycles.

CONCLUSIONS

Bisphosphonates are a promising treatment for low BMD and fragility fractures in children with JIA. However, the quality of the current evidence is variable and better studies are needed to more clearly assess their role.

Juvenile idiopathic arthritis: the paediatric perspective

Paediatric rheumatology is a relatively new specialty that has developed rapidly over the last 30 years. There have been major advances, which have included improvements in the classification and management of juvenile idiopathic arthritis (JIA). The former has led to enhanced international collaboration with disease registries, multicentre research and the development of new therapeutic agents. This has resulted in improved disease control and remission induction in many. There is, however, still significant morbidity associated with JIA during childhood, adolescence and adulthood, and challenges for the future include early identification of those with a poorer prognosis, appropriate administration of safe therapies and optimizing outcomes as young people move through adolescence into adulthood.

Principles of management of musculoskeletal conditions in children and young people

Musculoskeletal symptoms and rheumatic conditions are common throughout childhood and adolescence. Age- and development-appropriate care and management of children and young people with such conditions is vital, acknowledging that they are NOT small adults! The major aspect of both paediatric and adolescent rheumatology care which differentiates it from adult care is the fact that children and young people are still growing, in contrast to the ageing and senescence which characterizes adult rheumatology. Growth must be considered in the global sense, incorporating cognitive and psychosocial growth as well as physical growth. Likewise, the reciprocal influences of growth and a chronic rheumatic condition should be considered when caring for young people with childhood-onset rheumatic disease. This chapter will detail the general principles of management of such symptomatology with primary reference to chronic conditions.

Osteoporosis due to Glucocorticoid Use in Children with Chronic Illness

Osteoporosis is increasingly recognized as a complication of chronic childhood illnesses, particularly when glucocorticoids (GCs) are necessary for treatment. Elucidation of the mechanisms leading to bone fragility in these settings requires disentanglement of the relative contributions of myriad risk factors, including disease activity, muscle weakness, immobilization, delayed growth and puberty, compromised nutrition, and osteotoxic medications. Over the years, bone mass and density evaluations by dual energy X-ray absorptiometry (DXA) have become popular for assessing bone health in children; however, such measurements are difficult to interpret because of the confounding effect of bone size and the lack of DXA-based densitometric criteria for defining osteoporosis in childhood. Recently, a new diagnostic approach for evaluation of densitometric data in children has been suggested, driven by Frost's mechanostat theory. A diagnostic algorithm based on the mechanostat theory of bone-muscle development is proposed for the characterization of bone disease in children with chronic illness. In addition to DXA-based assessments, techniques such as peripheral quantitative computerized tomography and ilial histomorphometry, for which there are pediatric reference data, are gaining ground in the characterization of skeletal changes due to chronic illness. Although these diagnostic techniques expand our understanding of osteoporosis in children, they do not replace clinical assessment. Concrete clinical evidence for GC-induced bone fragility can be seen in spinal changes due to vertebral compression, with spinal morphometry emerging as an essential, but frequently overlooked, tool in the evaluation of children's bone health. Presently, osteoporosis treatment in the chronic illness setting remains experimental and should be restricted to clinical studies. Following an understanding of the natural history of GC-induced osteoporosis in children, randomized, placebo-controlled prevention and intervention trials will be the next step toward the development of clinical practice guidelines.

[Diagnosis and treatment of juvenile osteoporosis]

Bone mass is primarily genetically determined, but exogenous factors also play a major role. The prevention of osteoporosis can start from childhood, and optimal achievement of peak bone mass during childhood and adolescence is important in order to minimise future fracture risks. Chronic inflammatory diseases can have a detrimental effect on bone mass, by means of several mechanisms. Different diagnostic methods for detection and monitoring of osteoporosis are in use or under investigation. The role of calcium and vitamin D supplementation for the prevention and treatment of osteoporosis associated with paediatric rheumatic diseases remains to be established. New treatments such as bisphosphonates and calcitonin are now available, although their use in the paediatric age has been limited.

CALCIUM AND BONE MINERAL METABOLISM IN CHILDREN WITH CHRONIC ILLNESSES

Increased longevity and improved medical management of children with chronic illnesses has led to a focus on the short- and long-term consequences of these conditions on bone health. Bone loss is influenced by diet, malabsorption, and disease-related imbalances in bone turnover. It may be exacerbated by common medications, especially corticosteroids. Assessment of bone mass and quality, calcium absorption, kinetically derived rates of bone turnover, and biochemical markers of bone turnover have increased our knowledge of the pathophysiology of bone loss in these children as well as provided insights into possible therapeutic interventions. Increased intake of calcium and vitamin D, while useful, is unlikely to prevent or resolve bone loss in many chronically ill children. Emphasis on combination of nutritional interventions with exercise and newer bone-sparing therapies may be necessary.

Slowing of bone loss in patients with rheumatoid arthritis by long-term high-intensity exercise: results of a randomized, controlled trial

OBJECTIVE

Patients with rheumatoid arthritis (RA) are more at risk for the development of osteoporosis and osteoporotic fractures than are their healthy peers. In this randomized, controlled, multicenter trial, the effectiveness of a 2-year high-intensity weight-bearing exercise program (the Rheumatoid-Arthritis-Patients-In-Training [RAPIT] program) on bone mineral density (BMD) was compared with usual care physical therapy, and the exercise modalities associated with changes in BMD were determined.

METHODS

Three hundred nine patients with RA were assigned to an intervention group, either the RAPIT program or usual care physical therapy. The primary end points were BMD of the hip and spine. The exercise modalities examined were aerobic fitness, muscle strength, and, as a surrogate for those effects not directly measured by the RAPIT program, attendance rate.

RESULTS

The data on the 136 RAPIT participants and 145 usual care participants who completed the study were analyzed. The mean rate of decrease in hip BMD, but not in lumbar spine BMD, was smaller in patients participating in the RAPIT program when compared with that in the usual care group, with a mean decrease of 1.6% (95% confidence interval [95% CI] 0.8-2.5) over the first year and 0.5% (95% CI 1.1-2.0) over the second year. The change in hip BMD was significantly and independently associated with changes in both muscle strength (multivariate odds ratio [OR] 1.75, 95% CI 1.07-2.86) and aerobic fitness (OR 1.79, 95% CI 1.10-2.90), but not with the attendance rate (OR 1.00, 95% CI 0.99-1.00).

CONCLUSION

A long-term high-intensity weight-bearing exercise program for RA patients is effective in slowing down the loss of BMD at the hip. The exercise modalities associated with this effect are muscle strength and aerobic fitness.

Unmet education and training needs of rheumatology health professionals in adolescent health and transitional care

OBJECTIVES

To determine the perceived education and training needs of health professionals involved in transitional care for adolescents with juvenile idiopathic arthritis (JIA).

METHODS

Two distinct questionnaires to identify transitional issues in JIA were distributed to key health professionals (n = 908) and clinical personnel involved in the implementation of a transitional care programme (n = 22).

RESULTS

The first survey was completed by 263 professionals. Education needs were reported by 114 (43%) of health professionals. Transition issues and informational resources were the most frequently reported areas of need. The second survey was completed by 22 clinical personnel who rated 'lack of training', 'lack of teaching materials geared towards adolescents' and 'limited clinic time' as the main barriers to providing developmentally appropriate care to adolescents.

CONCLUSION

Unmet education and training needs of health care professionals exist in key areas of transitional care and provide useful directions for the development of future training programmes.

Bone disease in pediatric rheumatologic disorders

Children with rheumatic disorders have multiple risk factors for impaired bone health, including delayed growth and development, malnutrition, decreased weight-bearing activity, inflammation, and glucocorticoid therapy. The impact of rheumatic disease during childhood may be immediate, resulting in fragility fractures, or delayed, because of suboptimal peak bone mass accrual. Recent years have seen increased interest in the effects of pediatric rheumatic disorders on bone mineralization, such as juvenile rheumatoid arthritis, systemic lupus erythematosus, and juvenile dermatomyositis. This review outlines the expected gains in bone size and mass during childhood and adolescence, and summarizes the advantages and disadvantages of available technologies for the assessment of skeletal growth and fragility in children. The varied threats to bone health in pediatric rheumatic disorders are reviewed, with emphasis on recent insights into the molecular mechanisms of inflammation-induced bone resorption. The literature assessing bone deficits and risk factors for impaired bone health in pediatric rheumatic disorders is reviewed, with consideration of the strengths and limitations of prior studies. Finally, future research directions are proposed.

Frequency of osteopenia in adolescents with early-onset juvenile idiopathic arthritis: a long-term outcome study of one hundred five patients

OBJECTIVE

To determine the frequency of low bone mineral content (BMC) and low bone mineral density (BMD) as long-term complications in adolescents with early-onset juvenile idiopathic arthritis (JIA), and to identify disease variables, patient characteristics, and biochemical bone markers related to low bone mass.

METHODS

One hundred five (87%) of 121 adolescent patients with early-onset JIA (ages 13-19 years, 80 girls and 25 boys, mean age at onset of JIA 2.8 years), from a cohort first admitted to the hospital between 1980 and 1985, were assessed after a mean disease duration of 14.2 years. BMC and BMD of the total body, the lumbar spine at L2-L4, and the femoral neck were measured by dual-energy x-ray absorptiometry. Age- and sex-specific reference values from a pooled, healthy reference population were used to calculate Z scores. Low bone mass was defined as a Z score less than -1 SD.

RESULTS

Among the 103 adolescent JIA patients who underwent total-body imaging, 41% had low total-body BMC and 34% had low total-body BMD. Compared with adolescent JIA patients who had normal total-body BMC, those with low BMC had lower mean weight (P < 0.001), height (P < 0.001), lean mass (P < 0.001), and remission rates (P = 0.016), had longer duration of active disease (P = 0.013), had higher numbers of active and mobility-restricted joints (P < 0.001 and P = 0.001, respectively), had more disability (P = 0.011), had higher frequencies of joint erosions (P < 0.001), and had higher erythrocyte sedimentation rates (P = 0.033). In multiple linear regression analyses of total-body BMC, 88% of the variance was explained by the duration of active disease, the number of joints with restricted mobility, the bone area, urinary deoxypyridinoline values, age, weight, and height.

CONCLUSION

Forty-one percent of the adolescents with early-onset JIA had low bone mass >11 years after disease onset. The development of low total-body BMC was related to the duration of active disease, disease severity, measures of bone resorption, weight, and height.

Juvenile rheumatoid arthritis

Progress in achieving international consensus concerning the classification of juvenile idiopathic arthritis has been made, although further refinement and validation of these criteria is needed. It is hoped that this will facilitate more effective international collaboration in the study of these diseases, because much remains to be learned about genetic susceptibility, causation, pathogenesis, and treatment. Attention to the unique aspects of chronic arthritis in children such as impaired growth and macrophage activation syndrome may help to reduce disease-related morbidity and mortality. New biologic agents have substantially enhanced the treatment of JRA. The identification of reliable predictors of disease course and outcome is important in the rational and timely application of new therapies.

Osteoporosis

Bone mass is determined primarily by genetic influences, but exogenous factors may also play a major role. The prevention of osteoporosis can start at childhood. Optimal achievement of peak bone mass during childhood and adolescence is important to minimize future fracture risk. Chronic inflammatory diseases can have a detrimental effect on bone mass through a variety of mechanisms. Different diagnostic methods for detecting osteoporosis (eg, dual x-ray absorptiometry, quantitative computed tomography, ultrasounds) are in use or under investigation. New treatment options are available; among these, the use of bisphosphonates seems to be the more promising approach.

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.

Recovery from severe glucocorticoid-induced osteoporosis in an adolescent boy

An 18-yr-old boy presented with extreme back pain as the result of multiple vertebral fractures. At age 16 he had developed a tumor of the mesencephalon. A ventriculoperitoneal shunt was established surgically. One year later, he developed progressive neurologic deficits in his upper and lower limbs with an increase in the size of the tumor. He was treated by irradiation and high doses of glucocorticoids. Although the neurologic deficits progressively improved, he developed severe back pain resulting in complete immobilization for 3 mo in spite of neurologic recovery. Multiple vertebral fractures were diagnosed by X-ray. Bone density was extremely low (Z-score of -5.5 in the spine and -3.1 in the femoral neck). The patient was treated with calcium and vitamin D, calcitonin, bisphosphonates, physiotherapy, and progressive mobilization. Glucocorticoids were decreased and could be stopped as the neurologic deficits fully recovered. After 1 yr of treatment with intermittent i.v. pamidronate, bone density had increased by 40% in the spine and by 25% in the femoral neck despite growth arrest. He progressively recovered from back pain and is now, at age 20, fully ambulant, studying mechanical engineering, without neurologic sequelaes and free of glucocorticoids. Magnetic resonance imaging revealed that the tumor had disappeared. This case proves that treatment of symptomatic glucocorticoid-induced osteoporosis during puberty can be rewarding, even when multiple and invalidating vertebral fractures already exist.