Measurement of bone density in the pediatric population

Bone Health in Paediatric Inflammatory Bowel Disease

Paediatric inflammatory bowel disease (IBD) is often complicated by bone loss resulting in an increased risk of fractures and impaired quality of life. Underlying inflammation, nutritional deficiencies and glucocorticoid therapy are some of the factors contributing to secondary osteoporosis in IBD. Optimising nutrition, dietary supplementation and timely screening are essential in preventing bone loss. Bisphosphonate therapy remains the cornerstone of medical management of osteoporosis. This review explores the various mechanisms contributing towards poor bone health in IBD and the recent advances in diagnostic and preventive approaches along with updates in management strategies.

Influences on Skeletal Health and Bone Mineralization in Children

Bone is in its most active formation phase of mineralization in the pediatric and adolescent population. Peak bone mass is achieved around the late teens to early 20s. Deficient bone mineralization and decreased peak bone mass acquisition predispose an individual to childhood fractures or lifelong fracture risk. Adolescent fragility or stress fractures should prompt a secondary evaluation for the causes of a low bone mineral content, the root of a fracture. The purpose of this article is to review published literature that discusses the risk factors associated with a decreased bone mineral content in children from birth to the age of peak bone mass. The article also includes a public health planning model for pediatric osteoporosis.

Bone mineral density in pediatric heart transplanted patients: A retrospective single-center study at Skåne University Hospital in Lund 1988-2016

BACKGROUND

Impaired bone mineral density (BMD) and osteoporosis are commonly found in patients who have undergone heart transplantation (HT), which increases the risk for bone fractures which is associated with increased morbidity and mortality in adults. However, the long-term evolution of BMD after HT in pediatric patients has not been thoroughly investigated.

METHOD

Bone mineral density up to 10 years after HT was investigated in 30 patients who underwent HT at an age <20 years at Skåne University Hospital in Lund 1988-2016.

RESULTS

The total observed time was 235 person-years. Before HT, 86% had low BMD for chronologic age in the lumbar spine. In lumbar spine, BMD was significantly lower than normal for chronological age before HT (p = .034), but recovered at the 4th year (p = .009). In whole body, BMD was normal at the 4th annual check-up (p = .030) and remained so throughout the follow-up period. The median T score in the lumbar spine and femoral neck 10 years after HT did not differ between the two groups based on age at HT (<20 years vs 20 years or older; p = .779 in the lumbar spine and p = .388 in the femoral neck).

CONCLUSIONS

Patients who undergo HT at an age of <20 years have low BMD for chronological age already before HT, but BMD may recover completely within the first 4 years after HT. The results indicate no difference in BMD at 10 years after HT between pediatric and adult patients.

Low skeletal bone mineral density as a potential aetiological factor towards idiopathic condylar resorption

The aim of this study was to investigate the contributing factor of impaired skeletal quality in the pathogenesis of idiopathic condylar resorption (ICR). One hundred and twenty-six patients with MRI-confirmed ICR and 596 patients with disc displacement (DD) without a diminished condyle, of both sexes, were included. Dental examinations and retrospective surveys regarding temporomandibular joint symptoms and progression of maxillofacial deformities were conducted. Skeletal bone mineral density (BMD) was measured by dual energy X-ray absorptiometry (DXA) and converted to T-scores and Z-scores. Results showed that ICR patients had a smaller overbite (1.56±3.3 vs 3.05±2.0mm), larger overjet (4.9±2.4 vs 3.5±1.9mm), larger range of mouth opening (36.5±6.7 vs 33.6±7.1mm), and higher rates of anterior open bite and mandibular retrusion compared to DD patients (all P<0.001). ICR was associated with an increased probability of low skeletal BMD at chronological age in females (P=0.020) but not in males (P=0.095). This study indicates that reduced BMD may predispose females to an exacerbated condylar resorption process in addition to increased joint loading initiated from DD.

The role of using different reference population in the prevalence of low BMD in the thalassemia patients

Purpose

Prevalence of osteoporosis reported as high as 50% in thalassemia major patients. We compared bone density (BMD) of our patients with results of bone densitometry of participants of a national study, to find if BMD diagnosis is ethnicity sensitive or not.

Methods

In 177 adult beta thalassemia major patients and 490 normal subjects of 20-39 y/o range, dual-energy X-ray absorptiometry of the spine and femur performed. Normal subjects participated in Iranian Multi-center Osteoporosis Study (IMOS). Mean and standard deviation of normal ones achieved and Z-score of patients re-calculated based on normal Iranians. As BMD of normal participants and patients performed by devices of different brands, analyses done based on calculated standard BMD of all participants.

Results

BMD of patients was significantly lower than normal participants (P value <0.001). Frequency of Z-score ≤-2 found in 52% and 56% of patients in femur and spine regions, respectively. New Z-score of patients according to Iranian normal populations calculated. Frequency of this new Z-score ≤-2 found in 16% and 72% of patients in femur and spine regions, respectively.

Conclusions

We think in secondary osteoporosis, may be other cut-off points, especially according to BMD of normal population of that geographical region are needed.

Unaffected bone mineral density in Danish children and adolescents with type 1 diabetes

AIMS

Adults with type 1 diabetes mellitus (T1D) have decreased bone mineral density (BMD). Our study aimed at determining BMD and the association to metabolic control in children and adolescents with T1D.

METHODS

244 patients (113 girls) with a median age of 14.3 years and T1D duration of 1-16 years were included. A dual-energy X-ray absorptiometry scan assessed BMD Z-scores excluding the head (total body less head, TBLH). TBLH-BMD were then investigated for associations to diabetes relevant variables such as HbA1c, insulin treatment, anthropometry and physical activity.

RESULTS

In all participants the TBLH-BMD Z-score (0.22 ± 0.96) was significantly higher than the references. Separated by sex, TBLH-BMD Z-score in boys (0.11 ± 0.84) was no different from healthy peers whereas TBLH-BMD Z-score was significantly higher in girls (0.36 ± 1.09). The higher TBLH-BMD Z-score in girls were explained by higher BMI Z-scores. Participants with assumed final height (based on age) had an average TBLH-BMD Z-score of 0.78 ± 1.06, significantly higher than references independent of gender, HbA1c, height- and weight Z-scores. Multiple regression analyses showed that TBLH BMD Z-score associated negatively to HbA1c (P = 0.003), pump treatment (P = 0.019) and screen-time (P = 0.005) and positively to weight Z-score (P < 0.001). Physical activity, sex and puberty did not significantly associate to TBLH-BMD Z-score.

CONCLUSION

Unlike adults with T1D, BMD is not decreased in children and adolescents with T1D and even elevated after attained final height. As HbA1c negatively associates to BMD, decreased BMD may progress over time. Whether changes in microarchitecture or bone metabolism precede changes in BMD needs further investigation.

Effects of vitamin D and estrogen receptor polymorphisms on bone mineral density in adolescents with anorexia nervosa

Background Anorexia nervosa (AN) is a serious eating disorder that is associated with decreased bone mineral density (BMD) and greater lifetime risk for fractures. The aim of this study was to determine the correlation between BMD and genetic polymorphisms in AN. Methods This case-control study analyzed vitamin D receptor (VDR) (VDRBsml, VDRFokl) and estrogen receptor (ESR) (ESR1Xbal, ESR1Pvull) polymorphisms in 45 adolescents diagnosed with AN and 46 age-matched healthy controls. BMD values of the AN group were classified as low or normal, and polymorphisms were compared between cases and controls. The effects of body mass index (BMI), duration of disease and amenorrhea on BMD were also evaluated. Results In girls with AN, a positive effect of the bb genotype of VDRBsmI polymorphism on femur Z-scores (p = 0.103) and of the Ff genotype of VDRFokI polymorphism on vertebra Z-scores (p = 0.097) was observed. In boys with AN, a positive effect of the Ff genotype of VDRFokI polymorphism on vertebra BMD (g/cm2) was detected (p = 0.061). No association was detected between ESR polymorphisms. An inverse relationship was observed between BMD and duration of illness and amenorrhea. A direct relationship was detected between BMD and BMI. Conclusions Specific VDR gene polymorphism genotypes may have positive effects on BMD in patients with AN. Additionally, the lack of association between ESR gene polymorphisms on BMD could be attributed to the low estrogen status of the patient.

pQCT bone geometry and strength: population epidemiology and concordance in Australian children aged 11-12 years and their parents

OBJECTIVES

To describe the epidemiology and concordance of bone health in a population-based sample of Australian parent-child dyads at child age 11-12 years.

DESIGN

Population-based cross-sectional study (the Child Health CheckPoint) nested between waves 6 and 7 of the Longitudinal Study of Australian Children (LSAC).

SETTING

Assessment centres in seven cities around Australia, February 2015-March 2016.

PARTICIPANTS

of all participating CheckPoint families (n=1874), bone data were available for 1222 dyads (1271 children, 50% girls; 1250 parents, 86% mothers).

OUTCOME MEASURES

Peripheral quantitative CT (pQCT) of the non-dominant leg scanned at the 4% (distal) and 66% (mid-calf) tibial sites. Stratec XCT 2000 software generated estimates of bone density, geometry and polar stress-strain index.Parent-child concordance were assessed using Pearson's correlation coefficients and multivariable linear regression models. Percentiles were determined using survey weights. Survey weights and methods accounted for LSAC's complex sampling, stratification and clustering within postcodes.

RESULTS

Concordances were greater for the geometric pQCT parameters (periosteal circumference 0.38, 95% CI 0.33 to 0.43; endosteal circumference 0.42, 95% CI 0.37 to 0.47; total cross-sectional area 0.37, 95% CI 0.32 to 0.42) than density (cortical density 0.25, 95% CI 0.19 to 0.30). Mother-child and father-child values were similar. Relationships attenuated only slightly on adjustment for age, sex and body mass index. Percentiles and concordance are presented for the whole sample and by sex.

CONCLUSIONS

There is strong parent-child concordance in bone geometry and, to a lesser extent, density even before the period of peak adolescent bone deposition. This geometrical concordance suggests that future intergenerational bone studies could consider using pQCT rather than the more commonly used dual X-ray absorptiometry (DXA).

Investigating the bone mineral density in children with solid tumors in southern Iran: a case-control study

Along with increasing childhood cancer survival, there is increasing concern about its chronic complications. We showed that 20.5 and 45.9% of children with solid tumors in southern Iran had low bone mass for chronological age in lumbar and femoral area, which was associated with serum ferritin and hemoglobin. 52.4% of these children had vitamin D deficiency, as well.

PURPOSE/INTRODUCTION

Along with increasing the childhood cancer survival, there is increasing concern about the chronic complications of the disease and the related therapies. This study aims to compare the vitamin D status and bone mineral apparent density (BMAD) of these children with healthy ones and assess some possible associated factors.

METHOD

This case-control study enrolled 50 children with solid tumors and their age- and sex-matched controls. Dual-energy X-ray absorptiometry was used to assess bone mineral density. Body mass index, puberty, physical activity, sun exposure, and biochemical data were assessed.

RESULTS

52.4% of children with solid tumors had vitamin D deficiency, and there was no significant difference between the prevalence of vitamin D deficiency in patients and controls (P = 0.285). The prevalence of low bone mass for chronological age in lumbar area was 20.5 and 12.5% in patients and controls, respectively (P = 0.399). Lumbar spine BMD was associated with hemoglobin level (r = 0.468, P = 0.049), while low bone mass in femoral neck was associated with serum ferritin (859 ± 1037 in low bone mass vs. 178 ± 264 in without low bone mass, P = 0.039).

CONCLUSION

Vitamin D deficiency and low bone mass are prevalent among Iranian children with solid tumors. Future studies are warranted to investigate the best strategies to prevent and treat vitamin D deficiency and low bone mass in children surviving cancer.

Evaluation of bone mineral density in children with sickle-cell anemia and its associated factors in the south of Iran: a case-control study

Sickle-cell anemia is a hereditary hemoglobin disorder among children. We showed that the low bone mass is prevalent among these children, and it has a negative association with hemoglobin. In spite of using supplementary 200 IU/day vitamin D, 59.6% of children with sickle-cell anemia are vitamin D deficient. We suggest that early diagnosis and treatment of this problem could improve the bone health in them.

Osteoporosis in patients with erythropoietic protoporphyria

BACKGROUND

Erythropoietic protoporphyria (EPP) is a rare metabolic disease with painful photosensitivity due to protoporphyrin IX accumulation.

OBJECTIVES

To evaluate bone mineral density (BMD) and known osteoporosis risk factors in patients with EPP.

METHODS

Patients with EPP attending the Erasmus MC outpatient clinic who had undergone BMD measurements were included. Plasma 25 hydroxy (OH) vitamin D, alkaline phosphatase, parathyroid hormone and total protoporphyrin IX levels were measured; information on lifestyle, sunlight exposure and a bone-relevant physical exercise index [Bone Physical Activity Questionnaire (BPAQ) score] was obtained via questionnaires. BMD scores and the prevalence of osteopenia and osteoporosis in the EPP population were compared with a reference population.

RESULTS

Forty-four patients with EPP (23 female, 21 male; mean age 37·6 years) were included. The mean SDs of the T-scores were -1·12 for the lumbar spine and -0·82 for the femoral neck (both P < 0·001). Osteopenia was present in 36%; osteoporosis in 23%. Based on the reference population the expected prevalence was 15% and 1%, respectively. Prevalence of vitamin D deficiency was 50% (defined as a 25-OH vitamin D level < 50 nmol L^-1 ). Mean self-reported BPAQ score was 19·4 units (reference interval 19-24). Multiple linear regression analysis showed a significant influence of vitamin D deficiency and bone-relevant physical exercise score on BMD in patients with EPP.

CONCLUSIONS

The prevalence of osteoporosis and osteopenia is greatly increased in patients with EPP. Alkaline phosphatase (related to vitamin D deficiency) and amount of weight-bearing exercise are significantly correlated with low BMD in this population.

Low Vitamin D Levels are Associated With Need for Surgical Correction of Pediatric Fractures

BACKGROUND

There is growing concern over the relationship between the severity of pediatric fractures and low vitamin D [25-hydroxyvitaminD (25(OH)D)] status.

OBJECTIVE

Compare 25(OH)D levels and lifestyle of children with fractures to nonfracture controls to determine if 25(OH)D levels are associated with fractures and if there is a 25(OH)D fragility fracture threshold.

METHODS

Pediatric fracture and nonfracture controls were included. Bone health survey and medical record data were analyzed. Fractures were categorized using the Abbreviated Injury Scale (AIS). AIS 3 fractures were identified as fractures that required surgical intervention. Univariate and multivariable ordinal regression analyses were performed to identify potential risk factors for increased fracture severity.

RESULTS

A total of 369 fracture patients and 662 nonfracture controls aged 18 years and younger were included. Both groups' 25(OH)D levels were comparable. 25(OH)D was 27.5±8.9 in the fracture group compared with 27.4±9.1 ng/mL in nonfracture controls (P=0.914). AIS 3 fractures had lower 25(OH)D levels (24.6±9.3 ng/mL) versus AIS 1 and 2 (30.0±10.8 and 28.3±8.4, respectively, P=0.001). Univariate correlations for AIS severity were found with age (P=0.015) and outdoor playtime (P=0.042). Adjusted odds ratios for 25(OH)D levels <12 ng/mL was 55.4 (P=0.037), 25(OH)D between 12 and 20 ng/mL was 6.7 (P=0.039), 25(OH)D between 20 and 30 ng/mL was 2.8 (P=0.208), and 25(OH)D between 30 and 40 was 1.7 (P=0.518).

CLINICAL RELEVANCE

Occurrence of a pediatric fracture was not associated with 25(OH)D levels in our study. However, children with lower vitamin D levels were found to be at higher risk for more severe fractures. Early evidence suggests that the target serum level for 25(OH)D should be at least 40 ng/mL in patients less than 18 years of age as the relative risk of more severe fractures increased as 25(OH)D levels decreased <40 ng/mL.

LEVEL OF EVIDENCE

Level III.

Bone mineral density in children with acute leukemia and its associated factors in Iran: a case-control study

Acute leukemia is the most common malignancy in children. We showed that low bone mass is prevalent among children with leukemia, especially in femur. Serum calcium, exercise, chemotherapy protocol, and radiotherapy are the main contributing factors. We suggest that early diagnosis and treatment of this problem could improve bone health in them.

INTRODUCTION

Acute leukemia is the most common malignancy in children and has been reported to be associated with low bone mass. Due to lack of sufficient data about the bone mineral density of children with leukemia in the Middle East, and inconsistencies between possible associated factors contributing to decreasing bone density in these children, we aimed to conduct a case-control study in Iran.

MATERIALS AND METHODS

This case-control study was conducted on 60 children with acute leukemia and 60 age- and sex-matched healthy controls. Anthropometric data, sun exposure, puberty, physical activity, and mineral biochemical parameters were assessed. Bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry (DEXA). Data analysis was done by SPSS software v. 21.

RESULTS

Serum calcium was higher in the control group (P = 0.012) while serum phosphorous, alkaline phosphatase, and serum 25(OH)D₃ were higher in children with leukemia with P values of 0.04, 0.002, and 0.036, respectively. Sun exposure and physical activity were more in healthy controls (P values <0.001 and 0.003, respectively). Prevalence of vitamin D deficiency in case and control groups was 57.8 and 79.4 %, respectively. This prevalence was higher in healthy controls (P value = 0.007). Both lumbar and femoral neck bone mineral apparent density (BMAD) were higher in the control group (P value <0.001). Serum calcium, physical activity, and radiotherapy were the most relevant factors associated with lumbar BMAD. Femoral neck BMAD was associated with chemotherapy protocol.

CONCLUSION

Low bone mass for chronological age is prevalent among children with leukemia, especially in the femoral neck. Serum calcium, physical activity, chemotherapy protocol, and radiotherapy are the main contributing factors.

Bone and Spinal Muscular Atrophy

Spinal Muscular Atrophy (SMA) is an autosomal recessive neuromuscular disease, leading to progressive denervation atrophy in the involved skeletal muscles. Bone status has been poorly studied. We assessed bone metabolism, bone mineral density (BMD) and fractures in 30 children (age range 15-171 months) affected by SMA types 2 and 3. Eighteen children (60%) had higher than normal levels of CTx (bone resorption marker); 25-OH vitamin D was in the lower range of normal (below 20 ng/ml in 9 children and below 12 ng/ml in 2). Lumbar spine BMAD (bone mineral apparent density) Z-score was below -1.5 in 50% of children. According to clinical records, four children had sustained four peripheral fractures; on spine X-rays, we observed 9 previously undiagnosed vertebral fractures in 7 children. There was a significant inverse regression between PTH and 25-OH D levels, and a significant regression between BMC and BMAD values and the scores of motor-functional tests. Even if this study could not establish the pathogenesis of bone derangements in SMA, its main findings - reduced bone density, low 25OH vitamin D levels, increased bone resorption markers and asymptomatic vertebral fractures also in very young patients - strongly suggest that even young subjects affected by SMA should be considered at risk of osteopenia and even osteoporosis and fractures.

Use of selective serotonin reuptake inhibitors and bone mass in adolescents: An NHANES study

CONTEXT

Selective serotonin reuptake inhibitors (SSRIs) are commonly prescribed medications to treat depression and anxiety. SSRIs exert their effects by inhibiting the serotonin transporter and modulating extracellular serotonin levels, a neurotransmitter that has been shown to affect bone metabolism in animals. Studies in adults suggest a negative association between SSRI use and bone mineral density (BMD), greater rates of bone loss with SSRI use and increased risk of fractures. However, the results on bone mass have been inconsistent. Furthermore, there is a dearth of studies examining an association between SSRI use and bone mass in the pediatric and adolescent age group.

OBJECTIVE

To investigate associations between SSRI use and bone mass in adolescents.

DESIGN

Cross-sectional analysis of data from the 2005-2010 National Health and Nutrition Examination Study (NHANES).

PARTICIPANTS

4303 NHANES participants aged 12-20 years. The mean age was 15.65±2.42 years.

MAIN OUTCOMES

Total femur, femoral neck and lumbar spine bone mineral content (BMC) and BMD assessed via dual-energy X-ray absorptiometry (DXA).

RESULTS

62 out of 4303 subjects used SSRIs. SSRI use was an independent predictor of bone mass after adjusting for age, gender, height and weight Z score, socioeconomic status, physical activity, serum cotinine level and race/ethnicity. After multivariable adjustment, total femur BMC was 8.8% lower among SSRI users versus non-users (mean difference 2.98 g, SE±0.105 g, p=0.0006), while total femur BMD was 6.1% lower (mean difference 0.06 g/cm2, SE±0.002 g/cm2, p=0.016). Femoral neck BMC and BMD and lumbar spine BMC were similarly negatively associated with SSRI use. Compared to nonusers, lumbar spine BMC was 7% lower among SSRI users (mean difference 0.97 g, SE±0.048g, p=0.02) and BMD was 3.2% lower (mean difference 0.03 g/cm2, SE±0.015 g/cm2, p=0.09). Sub-analysis of those individuals treated for more than 6 months yield similar results. Finally, the association of SSRIs with bone mass persisted after excluding individuals with Body Mass Index (BMI) less than 5th percentile thus accounting for the possible confounding effect of anorexia nervosa, which can be treated with SSRIs.

CONCLUSION

In this NHANES study, adolescents treated with SSRIs had lower DXA measurements of the total femur and lumbar spine compared to SSRI non-users. These findings support the need for future prospective studies to examine the effects of SSRI use on bone mass in adolescents.

The clinical spectrum and pathophysiology of skeletal complications in lysosomal storage disorders

Lysosomal storage disorders affect multiple organs including the skeleton. Disorders with prominent skeletal symptoms are type 1 and 3 Gaucher disease, the mucopolysaccharidoses, the glycoproteinoses and pycnodysostosis. Clinical manifestations range from asymptomatic radiographical evidence of bone pathology to overt bone crises (Gaucher), short stature with typical imaging features known as dysostosis multiplex (MPS), with spine and joint deformities (mucopolysaccharidoses, mucolipidosis), or osteopetrosis with pathological fractures (pynodysostosis). The pathophysiology of skeletal disease is only partially understood and involves direct substrate storage, inflammation and other complex alterations of cartilage and bone metabolism. Current treatments are enzyme replacement therapy, substrate reduction therapy and hematopoietic stem cell transplantation. However, effects of these interventions on skeletal disease manifestations are less well established and outcomes are highly dependent on disease burden at treatment initiation. It is now clear that adjunctive treatments that target skeletal disease are needed and should be part of future research agenda.

Bone status in genetic syndromes: a review

More and more data seem to indicate the presence of an increasing number of syndromes and genetic diseases characterized by impaired bone mass and quality. Meanwhile, the improvement of etiopathogenetic knowledge and the employment of more adequate treatments have generated a significant increase in survival related to these syndromes and diseases. It is thus important to identify and treat bone impairment in these patients in order to assure a better quality of life. This review provides an updated overview of bone pathophysiology and characteristics in patients with Down, Turner, Klinefelter, Marfan, Williams, Prader-Willi, Noonan, and 22q11 deletions syndrome. In addition, some options for the treatment of the bone status impairment in these patients will be briefly discussed.

Glucocorticoid-induced osteoporosis: an update on effects and management

Glucocorticoids remain a cornerstone of guideline-based management of persistent asthma and allergic diseases. Glucocorticoid-induced osteoporosis (GIO) is the most common iatrogenic cause of secondary osteoporosis and an issue of concern for physicians treating patients with inhaled or oral glucocorticoids either continuously or intermittently. Patients with GIO experience fragility fractures at better dual-energy x-ray absorptiometry T-scores than those with postmenopausal or age-related osteoporosis. This might be explained, at least in part, by the effects of glucocorticoids not only on osteoclasts but also on osteoblasts and osteocytes. Effective options to detect and manage GIO exist, and a management algorithm has been published by the American College of Rheumatology to provide treatment guidance for clinicians. This review will summarize GIO epidemiology and pathophysiology and assess the role of inhaled and oral glucocorticoids in asthmatic adults and children, with particular emphasis on the effect of such therapies on bone health. Lastly, we will review the American College of Rheumatology GIO guidelines and discuss diagnostic and therapeutic strategies to mitigate the risk of GIO and fragility fractures.

Bone health in children and adolescents with perinatal HIV infection

The long-term impact on bone health of lifelong HIV infection and prolonged ART in growing and developing children is not yet known. Measures of bone health in youth must be interpreted in the context of expected developmental and physiologic changes in bone mass, size, density and strength that occur from fetal through adult life. Low bone mineral density (BMD) appears to be common in perinatally HIV-infected youth, especially outside of high-income settings, but data are limited and interpretation complicated by the need for better pediatric norms. The potential negative effects of tenofovir on BMD and bone mass accrual are of particular concern as this drug may be used more widely in younger children. Emphasizing good nutrition, calcium and vitamin D sufficiency, weight-bearing exercise and avoidance of alcohol and smoking are effective and available approaches to maintain and improve bone health in all settings. More data are needed to inform therapies and monitoring for HIV-infected youth with proven bone fragility. While very limited data suggest lack of marked increase in fracture risk for youth with perinatal HIV infection, the looming concern for these children is that they may fail to attain their expected peak bone mass in early adulthood which could increase their risk for fractures and osteoporosis later in adulthood.

Age trends of bone mineral density and percentile curves in healthy Chinese children and adolescents

The clinical utility of dual-energy X-ray absorptiometry (DXA) measurement requires appropriate normative values, designed to be diverse with respect to age, gender and ethnic background. The purpose of this study was to generate age-related trends for bone density in Chinese children and adolescents, and to establish a gender-specific reference database. A total of 1,541 Chinese children and adolescents aged from 5 to 19-years were recruited from southern China. Bone mineral density (BMD), bone mineral content (BMC), and bone area (BA) were measured for the total body (TB) and total body less head (TBLH). The height-for-age, height-for-BA, and BMC-for-BA percentile curves were developed using the least mean square method. TB BMD and TBLH BMD were highly correlated. After 18 years, TB BMD was significantly higher in boys than girls. For TB BMC and TBLH BMC, gender differences were found in age groups 12 years and 16-19 years; however, the TBLH BMD was significantly different between genders >16 years. The head region accounted for 13-52 and 16-49 % of the TB BMC in boys and girls, respectively. Furthermore, the percentages were negatively correlated with age and height. This study describes a gender-specific reference database for Chinese children and adolescents aged 5-19 years. These normative values could be used for clinical assessment in this population.

Normative data and percentile curves of bone mineral density in healthy Iranian children aged 9-18 years

We provide the first reference values for bone mineral content and bone mineral density according to age and sex in Iranian children and adolescents. The prevalence of hypovitaminosis D was high, and levels of physical activity were low in our sample. Multiple regression analyses showed age, BMI, and Tanner stage to be the main indicators of bone mineral apparent density.

PURPOSE

Normal bone structure is formed in childhood and adolescence. The potential determinants which interact with genetic factors to influence bone density include gender, nutritional, lifestyle, and hormonal factors. This study aimed to evaluate bone mineral content (BMC) and the bone mineral density (BMD) and factors that may interfere with it in Iranian children.

METHODS

In this cross-sectional study, 476 healthy Iranian children and adolescents (235 girls and 241 boys) aged 9-18 years old participated. BMC and BMD of the lumbar spine, femoral neck, and total body were measured by dual-energy X-ray absorptiometry using a Hologic Discovery device, and bone mineral apparent density (BMAD) of the lumbar spine and the femoral neck were calculated.

RESULTS

We present percentile curves by age derived separately for BMC, BMD, and BMAD of the lumbar spine, left femoral neck, and total body excluding the head for boys and girls. Maximum accretion of BMC and BMD was observed at ages of 11-13 years (girls) and 12-15 years (boys).The prevalence of hypovitaminosis D was high and physical activity was low in our participants. However, in multiple regression analyses, age, BMI, and Tanner stage were the main indicators of BMD and BMAD CONCLUSION: These normative data aid in the evaluation of bone density in Iranian children and adolescents. Further research to evaluate the evolution of BMD in Iranian children and adolescents is needed to identify the reasons for significant differences in bone density values between Iranian populations and their Western counterparts.

Long-term outcomes of children and adolescents who had cerebral palsy with secondary osteoporosis

OBJECTIVE

To investigate the long-term efficacy and index of treatment with vitamin D alone or with a bisphosphonate in children and adolescents who have cerebral palsy (CP) with secondary osteoporosis.

RESEARCH DESIGN AND METHODS

Thirty patients diagnosed with CP and secondary osteoporosis were analyzed for 5 years, and the efficacy of treatment was compared. Treatment was divided into three groups: The monotherapy group, consisting of patients taking only alfacalcidol (0.03 µg/kg/day); the polytherapy group, consisting of those taking alfacalcidol and risedronate (0.05 mg/kg/day); and the control group, consisting of patients who discontinued taking their medications for reasons unrelated to these therapies. Bone mineral density (BMD), bone-specific alkaline phosphate (BAP), and N-telopeptides of type I collagen (NTX/Cr) were measured on each patient just before and at discontinuation of treatment, after 6 months, and again at 1 and 3 years, respectively. The changes in BMD (ΔBMD), BAP (ΔBAP), and NTX/Cr (ΔNTX/Cr) were evaluated at these intervals, because the normal value of each parameter varies over time during childhood.

RESULTS

ΔBMD significantly increased in the polytherapy group at ≥1 year (p = 0.006), and the difference in BMD between the polytherapy and the control groups at ≥1 year was also significant (p = 0.005). ΔBAP was increased in the monotherapy and polytherapy groups at ≥1 year (p = 0.021 and p = 0.033). ΔNTX/Cr decreased in the polytherapy group at ≥1 year, which was consistent with the polytherapy group of the period from 1 month to 1 year (p = 0.033). The relation between ΔBMD to ΔBAP was a positive correlation in the second period in the monotherapy group (r = 0.46). And the relations between ΔBMD to ΔNTX/Cr were not recognized negative correlations in the monotherapy and polytherapy groups. Thus, ΔBMD reflected ossification of secondary osteoporosis in patients with CP, and ΔBAP and ΔNTX/Cr was significantly related to the increase and decrease of ΔBMD. There were no effects of other factors except sexual maturity. Limitations of this study include that each index of examination was the evaluation according to rate of change. Therefore, the results of this study were limited to longitudinal evaluations.

CONCLUSION

Evaluation according to ΔBMD and both methods of monotherapy and polytherapy were useful for CP patient taking antiepileptic drugs (AEDs) and regardless of sex. Especially, polytherapy for longer than 1 year led to improvement in BMD in children who had CP with secondary osteoporosis. BAP and NTX/Cr were useful for the index of the progression osteoporosis with or without these therapies.

Bone mineral density, fracture, and vitamin D in adolescents and young women using depot medroxyprogesterone acetate

STUDY OBJECTIVE

To evaluate bone mineral density (BMD) in adolescents and young adults treated with depot medroxyprogesterone acetate (DMPA).

DESIGN, SETTING, PARTICIPANTS

Eighty-three healthy subjects, 13-20 years old, who received at least 3 DMPA injections in an urban adolescent clinic and underwent dual energy x-ray absorptiometry (DXA) were evaluated by chart review.

MAIN OUTCOME MEASURES

Anthropometric data, DMPA use, BMD of the spine and hip, fracture history, and vitamin D status were collected.

RESULTS

Subjects were a median age of 16.4 years old (range 13-20 years) when DMPA was initiated. The median number of DMPA injections was 5 (range 3-18) before the first DXA. At the spine and hip, respectively, BMD was normal (Z-score > -1.0 SD) for most subjects (79%, 86%). Subjects who received > 5 injections were more likely to have low spinal BMD (Z-score ≤ -2.0 SD) at first DXA (P = .018). In 15 subjects with repeat DXA measurements, after an additional median 6 injections, spinal BMD Z-score decreased by -0.33 ± 0.10 (mean ± SD, P = .004), as did absolute BMD at the hip (-0.019 ± 0.007 g/cm(2), P = .014). History of fracture was not associated with initial or subsequent BMD measurements. Most (12/13, 92.3%) subjects with vitamin D measurements were deficient (25-hydroxy vitamin D < 20 ng/mL).

CONCLUSIONS

Most subjects on DMPA had normal BMD at first DXA. Low spinal BMD was associated with longer DMPA use, and some BMD measurements declined with prolonged use. Fracture history is not an absolute contraindication to DMPA use in this population. Studies are needed to determine possible benefits of vitamin D supplementation in DMPA users.

Osteoporosis in paediatric patients with spina bifida

The prevalence and morbidity associated with osteoporosis and fractures in patients with spina bifida (SB) highlight the importance of osteoporosis prevention and treatment in early childhood; however, the issue has received little attention. The method for the selection of appropriate patients for drug treatment has not been clarified.

OBJECTIVE

To review the literature concerning fracture risks and low bone density in paediatric patients with SB. We looked for studies describing state-of-the-art treatments and for prevention of secondary osteoporosis.

METHODS

Articles were identified through a search in the electronic database (PUBMED) supplemented with reviews of the reference lists of selected papers. The main outcome measures were incidence of fractures and risk factors for fracture, an association between bone mineral density (BMD) and occurrence of fracture, risk factors of low BMD, and effects of pharmacological and non-pharmacological treatments on BMD and on the incidence of fractures. We considered as a secondary outcome the occurrence of fractures in relation to the mechanism of injury.

RESULTS

Results indicated that patients with SB are at increased risk for fractures and low BMD. Risk factors that may predispose patients to fractures include higher levels of neurological involvement, non-ambulatory status, physical inactivity, hypercalciuria, higher body fat levels, contractures, and a previous spontaneous fracture. Limitations were observed in the number and quality of studies concerning osteoporosis prevention and treatment in paediatric patients with SB. The safety and efficiency of drugs to treat osteoporosis in adults have not been evaluated satisfactorily in children with SB.

Bone mineral density in healthy female adolescents according to age, bone age and pubertal breast stage

Objectives:

This study was designed to evaluate bone mineral density (BMD) in healthy female Brazilian adolescents in five groups looking at chronological age, bone age, and pubertal breast stage, and determining BMD behavior for each classification.

Methods:

Seventy-two healthy female adolescents aged between 10 to 20 incomplete years were divided into five groups and evaluated for calcium intake, weight, height, body mass index (BMI), pubertal breast stage, bone age, and BMD. Bone mass was measured by bone densitometry (DXA) in lumbar spine and proximal femur regions, and the total body. BMI was estimated by Quetelet index. Breast development was assessed by Tanner’s criteria and skeletal maturity by bone age. BMD comparison according to chronologic and bone age, and breast development were analyzed by Anova, with Scheffe’s test used to find significant differences between groups at P≤0.05.

Results:

BMD (g·cm^-2) increased in all studied regions as age advanced, indicating differences from the ages of 13 to 14 years. This group differed to the 10 and 11 to 12 years old groups for lumbar spine BMD (0.865±0.127 vs 0.672±0.082 and 0.689±0.083, respectively) and in girls at pubertal development stage B3, lumbar spine BMD differed from B5 (0.709±0.073 vs 0.936±0.130) and whole body BMD differed from B4 and B5 (0.867±0.056 vs 0.977±0.086 and 1.040±0.080, respectively).

Conclusion:

Bone mineralization increased in the B3 breast maturity group, and the critical years for bone mass acquisition were between 13 and 14 years of age for all sites evaluated by densitometry.

The impact of different types of physical activity on total and regional bone mineral density in young Brazilian athletes

Bone turnover is affected by exercise throughout the lifespan, especially during childhood and adolescence. The objective of this study was to investigate the impact of different sports on total and regional bone mineral density in male Brazilian adolescent athletes. Forty-six adolescents aged 10-18 years participated in the study: 12 swimmers, 10 tennis players, 10 soccer players, and 14 sedentary individuals. The athletes had engaged in physical activities for more than 10 h per week in the previous 6 months. Bone mineral density of the lumbar spine (L1-L4), left proximal femur region, and whole body was evaluated by dual-energy X-ray absorptiometry. Results showed higher mean values in the proximal femur region of tennis and soccer players (1.02 ± 0.18; 0.96 ± 0.16, respectively) than swimmers and controls (0.91 ± 0.14 and 0.87 ± 0.06, respectively) (P < 0.05). In relation to the impact of sporting activities based on bone age determination, we observed significant differences in bone mineral density at all evaluated sites at the end of puberty (16-18 years) compared with 10-12 years, with increases of 78% in the lumbar spine, 47% in the proximal femur, and 38% in the whole body.

Quantitative computed tomography is unreliable for measurement of bone mineral density in inadequately chelated adolescent patients with β-thalassemia major: a case-control study

BACKGROUND

Utility of quantitative computed tomography (QCT) for assessment of bone mineral density (BMD) in patients with thalassemia is not fully established. Majority of patients with thalassemia in India receive suboptimal iron chelation. There is paucity of data on BMD in this population. Aim was to assess BMD by lumbar QCT in adolescent patients with transfusion dependent β-thalassemia major and compare with controls.

PROCEDURE

Study was conducted prospectively, over 15 months. Single energy QCT was performed through first three lumbar vertebrae.

RESULTS

Forty-five patients were enrolled (age: 10-19 years). Thirty-eight normal siblings of patients with thalassemia patients served as controls. Forty percent patients weighed <3rd percentile, 64% were stunted, and 40% had suboptimal sexual maturity scores. Eighteen (40%) patients were on iron chelation with deferiprone. Mean serum ferritin was 2,800 ± 1,473 ng/ml. Mean BMD (mg/cu mm) of cases and controls was 194.5 ± 27.1 and 170.4 ± 28.84, respectively (P = 0.0002). The mean BMD of patients with ferritin <2,000 ng/ml and those with a higher ferritin was 181.2 ± 14.9 and 196.7 ± 25, respectively (P = 0.07). The finding of increased BMD in patients with thalassemia is in stark contrast to published reports. Patients had several risk factors for low BMD, including growth retardation, delayed puberty, and iron overload.

CONCLUSION

Single energy QCT of lumbar vertebrae is not reliable for measurement of BMD in inadequately chelated patients with β-thalassemia major. The deposition of iron in bone tissue may result in increased X-ray attenuation values of trabecular bone.

Bone mineral density and functional measures in patients with arthrogryposis

BACKGROUND

Patients with arthrogryposis often report decreased ambulation and physical activity. Given that skeletal mineralisation is responsive to force, we identified the need to characterize bone mineral density and functional measures in this population, and conducted a cross-sectional study to establish a reference for future investigations.

METHODS

Thirty consecutive patients aged 5 to 18 years with either the diagnosis of amyoplasia or nonsyndromic arthrogryposis with predominantly lower extremity involvement underwent bone densitometry testing, and lumbar spine Z-scores were calculated against an age and sex-matched control population as is customary in children. Pediatric outcomes data collection instrument (PODCI) and functional independence measure for Children (WeeFIM) assessment forms were completed. Mean Z-scores, PODCI, and WeeFIM scores were calculated. Statistical analysis was performed to compare lumbar spine Z-scores between patients divided by ambulatory status and to correlate WeeFIM and PODCI scores.

RESULTS

Mean lumbar spine Z-score was -0.47, with 73% of Z-scores being <0. Mean Z-score among nonambulators or home ambulators was -1.05, as compared to a mean Z-score among limited and unlimited community ambulators of -0.14 with a trend toward significance (P=0.10), and a dose-response relationship between higher bone density and increasing ambulatory function. Mean WeeFIM self-care and mobility quotient scores were 67.5/100 and 70.9/100, respectively. PODCI normative scores were decreased for upper extremity (10/50), transfer/basic mobility (-17/50), and sports/physical function (4/50), but normal in pain/comfort (45/50) and happiness (49/50). A linear relationship was noted between functional ambulation level and WeeFIM quotient and PODCI normative scores. There was good correlation between WeeFIM mobility and PODCI transfers and basic mobility standardised scores (R=0.86).

CONCLUSIONS

This is the first study to measure bone mineral density in children with arthrogryposis, and shows it to be lower than age-matched means, especially in patients with limited ambulation. Objective measures of functional ability (WeeFIM and PODCI) are decreased and demonstrate a linear relationship with ambulatory level. Further investigation is needed to quantify long-term effects of entering adulthood with below average bone mineral density in patients with arthrogryposis.

LEVEL OF EVIDENCE

Level II.

Fractures in myelomeningocele

Background

In patients with myelomeningocele (MMC), a high number of fractures occur in the paralyzed extremities, affecting mobility and independence. The aims of this retrospective cross-sectional study are to determine the frequency of fractures in our patient cohort and to identify trends and risk factors relevant for such fractures.

Materials and methods

Between March 1988 and June 2005, 862 patients with MMC were treated at our hospital. The medical records, surgery reports, and X-rays from these patients were evaluated.

Results

During the study period, 11% of the patients (n = 92) suffered one or more fractures. Risk analysis showed that patients with MMC and thoracic-level paralysis had a sixfold higher risk of fracture compared with those with sacral-level paralysis. Femoral-neck z-scores measured by dual-energy X-ray absorptiometry (DEXA) differed significantly according to the level of neurological impairment, with lower z-scores in children with a higher level of lesion. Furthermore, the rate of epiphyseal separation increased noticeably after cast immobilization. Mainly patients who could walk relatively well were affected.

Conclusions

Patients with thoracic-level paralysis represent a group with high fracture risk. According to these results, fracture and epiphyseal injury in patients with MMC should be treated by plaster immobilization. The duration of immobilization should be kept to a minimum (<4 weeks) because of increased risk of secondary fractures. Alternatively, patients with refractures can be treated by surgery, when nonoperative treatment has failed.