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

Disease Damage in Juvenile Idiopathic Arthritis

OBJECTIVES

To estimate the prevalence and predictors of disease-related damage in children with juvenile idiopathic arthritis (JIA) in a resource-limited setting.

METHODS

A single-centre study was conducted from January 2021 - December 2022. Children (≤ 18 y) diagnosed with JIA as per International League of Associations for Rheumatology (ILAR) criteria, with a disease duration of more than one year, were enrolled for this study. The articular and extra-articular damage was assessed using the juvenile arthritis damage index (JADI) and modified JADI scores. Disease activity and disabilities were evaluated using the clinical juvenile arthritis disease activity score (cJADAS) and Childhood Health Assessment Questionnaire (CHAQ).

RESULTS

One hundred and five children [44% (n = 42) boys] with JIA were enrolled in the study. The mean (SD) age of children at enrolment was 158 (46.2) mo. The median (IQR) disease duration was 48 (36-72) mo. Articular damage (JADI score ≥ 1) was present in 48.6%, and extra-articular damage (JADI-E ≥ 1) was observed in 21.9% of children. Half of the children (n = 22) with enthesitis-related arthritis (ERA) had joint damage (modified JADI score ≥ 1). Four children had ocular damage due to uveitis. Among the factors associated with articular damage, the odds of articular damage were high in those with positive rheumatoid factor (RF) and/ or anti-cyclic citrullinated peptides (CCPs) [OR: 4.4, 95% CI (1.00-19.60)].

CONCLUSIONS

48.6% of children with JIA had articular damage, while 21.9% of the children had extra-articular damage. Children with RF and/ or anti-CCP positivity are associated with higher odds of joint damage.

Bone erosions associated with systemic bone loss on HR-pQCT in women with longstanding polyarticular juvenile idiopathic arthritis

OBJECTIVES

To analyze longstanding polyarticular juvenile idiopathic arthritis (pJIA) for possible associations between localized bone damage (erosions), and systemic bone loss. Besides, to compare the systemic bone mass of pJIA with healthy controls.

METHODS

Thirty-four pJIA women and 99 healthy controls (HC) were included. Radius and tibia of all subjects were scanned by HR-pQCT. Volumetric bone mineral density (vBMD), bone microarchitecture, and -finite element parameters were analyzed. Patients underwent HR-pQCT of 2nd and 3rd metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joints of the dominant hand, for bone erosions quantification.

RESULTS

The mean age of patients was 31.5 ± 7.4yrs with a mean disease duration of 21.7 ± 9.2yrs. Bone erosions were detectable in 79% of patients. The number of bone erosions was positively correlated with cortical porosity (Ct.Po) at tibia (r = 0.575, p = 0.001), and radius (r = 0.423, p = 0.018); and negatively correlated with cortical vBMD at tibia (r=-0.420, p = 0.015). In a logistic regression analysis, adjusted for anti-CCP, the presence of bone erosions was independently associated with Ct.Po at radius (p = 0.018) and cortical vBMD at tibia (p = 0.020). Moreover, cortical and trabecular vBMD, trabecular number, and μ-finite element parameters were decreased in patients compared to HC (p < 0.05).

CONCLUSION

Bone erosions in longstanding pJIA women were associated with decreased cortical bone parameters, and these patients showed systemic bone impairment at peripheral sites compared with healthy controls.

Bone Health in Children with Rheumatic Disorders: Focus on Molecular Mechanisms, Diagnosis, and Management

Bone is an extremely dynamic and adaptive tissue, whose metabolism and homeostasis is influenced by many different hormonal, mechanical, nutritional, immunological and pharmacological stimuli. Genetic factors significantly affect bone health, through their influence on bone cells function, cartilage quality, calcium and vitamin D homeostasis, sex hormone metabolism and pubertal timing. In addition, optimal nutrition and physical activity contribute to bone mass acquisition in the growing age. All these factors influence the attainment of peak bone mass, a critical determinant of bone health and fracture risk in adulthood. Secondary osteoporosis is an important issue of clinical care in children with acute and chronic diseases. Systemic autoimmune disorders, like juvenile idiopathic arthritis, can affect the skeletal system, causing reduced bone mineral density and high risk of fragility fractures during childhood. In these patients, multiple factors contribute to reduce bone strength, including systemic inflammation with elevated cytokines, reduced physical activity, malabsorption and nutritional deficiency, inadequate daily calcium and vitamin D intake, use of glucocorticoids, poor growth and pubertal delay. In juvenile arthritis, osteoporosis is more prominent at the femoral neck and radius compared to the lumbar spine. Nevertheless, vertebral fractures are an important, often asymptomatic manifestation, especially in glucocorticoid-treated patients. A standardized diagnostic approach to the musculoskeletal system, including prophylaxis, therapy and follow up, is therefore mandatory in at risk children. Here we discuss the molecular mechanisms involved in skeletal homeostasis and the influence of inflammation and chronic disease on bone metabolism.

Vitamin D Supplementation in Patients with Juvenile Idiopathic Arthritis

Vitamin D has been implicated in the pathogenesis of skeletal disorders and various autoimmune disorders. Vitamin D can be consumed from the diet or synthesized in the skin upon ultraviolet exposure and hydroxylation in the liver and kidneys. In its bioactive form, vitamin D exerts a potent immunomodulatory effect and is important for bone health. Juvenile idiopathic arthritis (JIA) is a collection of inflammatory joint diseases in children that share the manifestation of inflamed synovium, which can result in growth arrest, articular deformity, bone density loss, and disability. To evaluate the potential effect of vitamin D on JIA disease manifestations and outcomes, we review the role of vitamin D in bone metabolism, discuss the mechanism of vitamin D in modulating the innate and adaptive immune systems, evaluate the clinical significance of vitamin D in patients with JIA, and summarize the supplementation studies.

Bone mass and vertebral fractures in South African children on prolonged oral glucocorticoids for chronic non-malignant illnesses

Introduction

We hypothesized that the prevalence of vertebral fractures would be low and that bone mineral density (BMD) would be less severely affected in a black South African (SA) population treated with glucocorticoids (GCs) than that reported in mainly white populations.

Methods

All children aged 5–17.9 years with chronic non-malignant illnesses who were on GCs (intravenous or oral) for greater than 3 months duration were evaluated. DXA scans were performed using a Hologic Discovery machine (Software version Apex 4.0.2) and the Hologic paediatric reference database. Whole body less head (WBLH) and lumbar spine (LS) bone mineral content (BMC) and density (BMD) Z-scores unadjusted and adjusted for height were calculated using the Zemel equation calculator.

Results

Seventy-two patients (49% with renal, 24% with rheumatic, 14% with neurological, 11% with hepatic and 3% with respiratory conditions; mean age 11.6 ± 3.3 years, 57% boys, 92% SA black) were enrolled. The mean duration of GC treatment was 34.1 (±25.1) months. Mean WBLH and LS height adjusted BMD Z-scores were −1.2 ± 1.5 and −0.9 ± 1.0 respectively. Eleven percent of patients had a LS height adjusted BMD Z-score ≤ −2. The prevalence of vertebral fractures on lateral vertebral fracture assessment (VFA) was 15% (11 of 72 patients).

Conclusion

The prevalence of vertebral fractures (15%) in predominantly black children on GCs with chronic non-malignant illnesses is similar to that reported from North America suggesting that routine yearly DXA scans including VFA are warranted in this highly at-risk population.

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Prevalence of vertebral fractures in black South African children on GCs is 15%.

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Majority of patients had 25(OH)D levels >30 nmol/L.

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A quarter of the patients with vitamin D deficiency had a LS BMD Z score ≤ −2.

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None of the vitamin D deficient patients had vertebral fractures.

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Routine yearly DXA scans are thus warranted on all children treated with GCs.

New Insights Into Monogenic Causes of Osteoporosis

Osteoporosis, characterized by deteriorated bone microarchitecture and low bone mineral density, is a chronic skeletal disease with high worldwide prevalence. Osteoporosis related to aging is the most common form and causes significant morbidity and mortality. Rare, monogenic forms of osteoporosis have their onset usually in childhood or young adulthood and have specific phenotypic features and clinical course depending on the underlying cause. The most common form is osteogenesis imperfecta linked to mutations in COL1A1 and COL1A2, the two genes encoding type I collagen. However, in the past years, remarkable advancements in bone research have expanded our understanding of the intricacies behind bone metabolism and identified novel molecular mechanisms contributing to skeletal health and disease. Especially high-throughput sequencing techniques have made family-based studies an efficient way to identify single genes causative of rare monogenic forms of osteoporosis and these have yielded several novel genes that encode proteins partaking in type I collagen modification or regulating bone cell function directly. New forms of monogenic osteoporosis, such as autosomal dominant osteoporosis caused by WNT1 mutations or X-linked osteoporosis due to PLS3 mutations, have revealed previously unidentified bone-regulating proteins and clarified specific roles of bone cells, expanded our understanding of possible inheritance mechanisms and paces of disease progression, and highlighted the potential of monogenic bone diseases to extend beyond the skeletal tissue. The novel gene discoveries have introduced new challenges to the classification and diagnosis of monogenic osteoporosis, but also provided promising new molecular targets for development of pharmacotherapies. In this article we give an overview of the recent discoveries in the area of monogenic forms of osteoporosis, describing the key cellular mechanisms leading to skeletal fragility, the major recent research findings and the essential challenges and avenues in future diagnostics and treatments.

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.

Bone mineral density is compromised in very long-term survivors of irradiated childhood brain tumor

INTRODUCTION

The increase in the number of childhood brain tumor survivors warrants detailed research to increase our knowledge regarding the possible physical and psychosocial adverse outcomes of tumor and tumor therapy. The aim of this study was to evaluate the current bone health by measuring the bone mineral density (BMD) in irradiated, adult long-term survivors of childhood brain tumors.

MATERIAL AND METHODS

We studied a national cohort of 74 adult survivors of childhood brain tumors treated with irradiation in Finland between 1970 and 2008. Dual X-ray absorptiometry (DXA) was performed for the femoral necks, total hips, and lumbar spine. Laboratory tests were conducted for evaluating the pituitary, thyroid, and gonadal functions. The participants were interviewed, examined clinically, and the disease and treatment related data were retrieved from the patient files.

RESULTS

One fourth of the patients (23.6%) had sex- and age-normalized z-scores below the expected range for age (z-score ≤ -2.0). Mean BMD scores were decreased in all the DXA measurement sites. Male sex was associated with low BMD (p < .05), while body mass index (BMI) had a significant positive association with BMD (p < .01). Mode of irradiation (with or without spinal irradiation) or inclusion of chemotherapy in the treatment did not affect BMD significantly. However, patients with a ventriculoperitoneal shunt had lower BMD than those without a shunt (p < .05). Follicle stimulating hormone (FSH) and luteinizing hormone (LH) were negatively associated with BMD in women (p < .05). However, a higher cumulative dose of glucocorticoids during treatment was not associated with lower BMD, while low BMD was significantly associated with previous fractures in long bones.

DISCUSSION

Low BMD should be taken in consideration in treatment of irradiated childhood brain tumor survivors especially in those with previous fractures in long bones.

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.

Incident Vertebral Fractures and Risk Factors in the First Three Years Following Glucocorticoid Initiation Among Pediatric Patients With Rheumatic Disorders

Vertebral fractures are an important yet underrecognized manifestation of osteoporosis in children with chronic, glucocorticoid-treated illnesses. Our goal was to determine the incidence and clinical predictors of vertebral fractures in the 3 years following glucocorticoid initiation among pediatric patients with rheumatic disorders. Incident vertebral fractures were evaluated according to the Genant semiquantitative method on lateral radiographs at baseline and then annually in the 3 years following glucocorticoid initiation. Extended Cox models were used to assess the association between vertebral fractures and clinical risk predictors. A total of 134 children with rheumatic disorders were enrolled in the study (mean ± standard deviation (SD) age 9.9 ± 4.4 years; 65% girls). The unadjusted vertebral fracture incidence rate was 4.4 per 100 person-years, with a 3-year incidence proportion of 12.4%. The highest annual incidence occurred in the first year (6.0%; 95% confidence interval (CI) 2.9% to 11.7%). Almost one-half of the patients with fractures were asymptomatic. Every 0.5 mg/kg increase in average daily glucocorticoid (prednisone equivalents) dose was associated with a twofold increased fracture risk (hazard ratio (HR) 2.0; 95% CI 1.1 to 3.5). Other predictors of increased vertebral fracture risk included: (1) increases in disease severity scores between baseline and 12 months; (2) increases in body mass index Z-scores in the first 6 months of each 12-month period preceding the annual fracture assessment; and (3) decreases in lumbar spine bone mineral density Z-scores in the first 6 months of glucocorticoid therapy. As such, we observed that a clinically significant number of children with rheumatic disorders developed incident vertebral fractures in the 3 years following glucocorticoid initiation. Almost one-half of the children were asymptomatic and thereby would have been undiagnosed in the absence of radiographic monitoring. In addition, discrete clinical predictors of incident vertebral fractures were evident early in the course of glucocorticoid therapy.

The Child with Multiple Fractures, What Next?

Fractures are common during childhood; however, they can also be the presenting symptom of primary or secondary causes of bone fragility. The challenge is to identify those children who warrant further investigation. In children who present with multiple fractures that are not commonly associated with mild to moderate trauma or whose fracture count is greater than what is typically seen for their age, an initial evaluation, including history, physical examination, biochemistry, and spinal radiography, should be performed. In children with bone pain or evidence of more significant bone fragility, referral for specialist evaluation and consideration of pharmacologic treatment may be warranted.

High adiposity and serum leptin accompanied by altered bone turnover markers in severe juvenile idiopathic arthritis

OBJECTIVE

To evaluate interactions between skeleton and adipose tissue, and association of adipokines and bone turnover markers with disease-related factors in patients with severe juvenile idiopathic arthritis (JIA).

METHODS

Forty-nine patients (median age 14.8 yrs, median disease duration 10.2 yrs) with refractory polyarticular JIA and 89 sex-matched and age-matched healthy controls participated in the study. Study subjects underwent clinical examination, body composition assessment with dual-energy X-ray absorptiometry, and analyses for leptin, adiponectin, and bone turnover markers.

RESULTS

Patients with JIA were shorter and more often overweight (p = 0.001) or obese (p < 0.001) than controls. They had significantly higher serum leptin, even when adjusted for fat mass (p < 0.001), than did controls. Adiponectin did not differ between the groups. Concentration of carboxyterminal telopeptide of type I collagen was higher (p = 0.006) in patients. The inverse association between leptin and bone turnover markers disappeared in controls but was strengthened in patients when adjusted for fat mass. Leptin, adiponectin, or bone markers did not associate with variables of disease activity.

CONCLUSION

Patients with severe JIA had high adiposity accompanied by increased bone resorption. Their serum leptin was higher, even independently of fat mass. Leptin tended to associate inversely with bone turnover markers but did not associate with variables of disease activity.

Comparison of bone mass and quality determinants in adolescents and young adults with juvenile systemic lupus erythematosus (JSLE) and juvenile idiopathic arthritis (JIA)

BACKGROUND

Few prospective data have been published on the comparison of bone density and quality in homogeneous groups of patients with juvenile systemic lupus erythematosus (JSLE) and juvenile idiopathic arthritis (JIA).

OBJECTIVE AND HYPOTHESIS

The objective of this study is to perform a longitudinal evaluation of the prevalence and the characteristics of bone mass and quality and to evaluate the differences on the bone parameters, using DXA, pQCT and QUS.

POPULATION AND/OR METHODS

Forty-three JSLE patients (35 females, 8 males, median age 18.8, range 14.0-34.1 years) have been studied with DXA, pQCT and QUS scans and compared with 138 JIA patients (112 females, 26 males, median age 18.9, range 13.4-33.2 years), and 79 controls (59 females, 20 males; median age 19.3, range 13.5-36.5 years). Of these, 39 patients (32 females and 7 males, median age 20.3, range 16.6-36.8 years) with JSLE were followed longitudinally and compared with 131 patients (108 females, 23 males median age 20.7, range 15.8-37.1 years) with JIA and 63 controls (48 females, 15 males; median age 21.9, range 15.5-38.3 years).

RESULTS

JSLE patients have a higher bone cortical density (CrtBMD) than controls and JIA patients (p < 0.005). However, JSLE and JIA patients have a significantly reduced bone trabecular density (TrbBMD) compared to controls (p < 0.0001), with no differences between JSLE and JIA. In addition, JIA patients show a significantly reduced muscle area (MuscleCSA) compared to JSLE and controls (p < 0.001). Conversely, fat area (FatCSA) is significantly increased both in JIA and JSLE patients when compared to controls (p < 0.001), with no differences between the JSLE and JIA groups. Analogous results are observed in the polar resistance to stress (SSIp). On longitudinal evaluation, contrary to CrtBMD, the difference between BMAD SDS, TrbBMD, MuscleCSA and FatCSA remains unchanged; in JSLE patients, SSIp is stable in comparison to JIA and controls without any difference between the two groups.

CONCLUSIONS

The evaluation of bone density and structure parameters in JSLE patients highlights significant differences compared with JIA patients and controls. These data might indicate a different pathogenesis of bone damage in the two entities, and suggest a different diagnostic and therapeutic approach to improve the peak bone mass.

Diagnosis of Osteoporosis in Children and Adolescents

Osteoporosis is traditionally regarded as a disease of elderly women. However, this bone disorder occurs in patients of both sexes and of all ages and is also increasingly recognised in the paediatric setting. In particular, patients, including young children, with other chronic diseases are at risk of developing bone fragility. There are also several forms of hereditary osteoporosis, which should be identified at an early stage to ensure adequate treatment. The diagnosis of osteoporosis in children is challenging, since their bone mineral density (BMD) is affected by growth and pubertal development. In addition to low BMD, a child must also exhibit a significant proneness to fractures before the osteoporosis diagnosis can be made. Through early diagnosis and treatment for paediatric bone fragility, we can also ameliorate bone health in adulthood. In this article we review the aetiology, known risk factors and the diagnostic criteria of osteoporosis in the young.

Adding to complexity: comorbidity in paediatric rheumatic disease

Novel therapies including biologic agents offer paediatric rheumatologists significant opportunity to improve long-term prognosis for children with rheumatic disease. However, comorbidities related to the diseases themselves and their treatments pose specific challenges to be overcome. Prompt recognition and appropriate management will improve quality of life, effectiveness of treatment and overall prognosis. In this review, we discuss key areas of comorbidity frequently encountered in paediatric rheumatology including cardiovascular, renal, genito-urinary and visual comorbidity, bone health, drug-related issues and the influence of rheumatic disease on growth and puberty.