Skeletal status and laboratory investigations in adolescent girls with anorexia nervosa

Peripheral Biomarkers of Anorexia Nervosa: A Meta-Analysis

The pathogenesis of anorexia nervosa (AN) has been hypothesized to involve several biological systems. However, reliable biomarkers for AN have yet to be established. This study was aimed to identify statistically significant and clinically meaningful peripheral biomarkers associated with AN. A systematic literature search was conducted to identify studies published in English from inception until 30 June 2022. We conducted two-level random-effects meta-analyses to examine the difference between AN and comparison groups across 52 distinct biomarkers and found that acylated ghrelin, adrenocorticotropic hormone (ACTH), carboxy-terminal collagen crosslinks (CTX), cholesterol, cortisol, des-acyl ghrelin, ghrelin, growth hormone (GH), obestatin, and soluble leptin receptor levels were significantly higher in cases of AN compared with those in non-AN controls. Conversely, C-reactive protein (CRP), CD3 positive, CD8, creatinine, estradiol, follicle-stimulating hormone (FSH), free thyroxine, free triiodothyronine, glucose, insulin, insulin-like growth factor 1 (IGF-1), leptin, luteinizing hormone, lymphocyte, and prolactin levels were significantly lower in AN compared with those in non-AN controls. Our findings indicate that peripheral biomarkers may be linked to the pathophysiology of AN, such as processes of adaptation to starvation. Scientific investigation into peripheral biomarkers may ultimately yield breakthroughs in personalized clinical care for AN.

Radiofrequency echographic multispectrometry (REMS): an innovative technique for the assessment of bone status in young women with anorexia nervosa

PURPOSE

Reduced bone mineral density (BMD) and increase risk of fragility fracture are common complication of anorexia nervosa (AN). BMD by dual-energy X-ray absorptiometry (DXA) present several limits in subjects with AN. This study aimed to evaluate the usefulness of the new Radiofrequency echographic multispectrometry (REMS) technique in the assessment of bone status in young women with AN.

METHODS

In a cohort of 50 subjects with restrictive AN and in 30 healthy controls, we measured BMD at the lumbar spine (LS-BMD), at femoral neck (FN-BMD) and total hip (TH-BMD) using both DXA and REMS technique.

RESULTS

BMD evaluated by DXA and REMS technique at all measurement sites were all significantly (p < 0.01) lower in subjects suffering from AN subjects than in controls. Good correlations were detected between BMD by DXA and BMD by REMS measurements at LS (r = 0.64, p < 0.01) at FN (r = 0.86, p < 0.01) and at TH (r = 0.84, p < 0.01) in subjects suffering from AN. Moreover, Bland-Altman analysis confirmed the good agreement between the two techniques. The subjects suffering from AN with previous vertebral fragility fractures presented lower values of both BMD-LS and BMD-TH by DXA and by REMS with respect to those without fractures; however, the difference was significant only for BMD-TH by REMS (p < 0.05).

CONCLUSIONS

Our data suggest that REMS technique due to its characteristic of precision and reproducibility may represent an important tool for the evaluation of the changes in bone status in AN young women, especially during the fertile age and in case of pregnancy and breastfeeding.

LEVEL OF EVIDENCE

Level of evidence: level III cohort study.

Changes in trabecular bone score and bone density in female adolescents with anorexia nervosa: a longitudinal study

Impaired bone health is a common complication of anorexia nervosa (AN). We aimed to assess longitudinal changes in bone mineral density (BMD) and trabecular bone score (TBS), a measure of bone quality, in female adolescents with anorexia nervosa (AN). We conducted a retrospective longitudinal study of 41 female adolescents with AN who underwent two dual-energy X-ray absorptiometry (DXA) scans. Clinical data, including age, weight, height, body mass index (BMI), and DXA measurements were retrieved from the medical charts. Lumbar bone mineral apparent density (BMAD) was calculated to correct for size. Changes (Δ) in BMD, BMAD, and TBS were examined for correlations with clinical characteristics. Mean ages at the time of DXA scans were 14.8±1.9 and 16.8±2.0 years. There was a significant improvement in anthropometric parameters and DXA measurements at the second DXA scan. However, these values were still significantly lower than expected in the general population. The Δlumbar BMD Z-score was 0.3±0.7, the Δlumbar BMAD Z-score was 0.2±0.7 and the ΔTBS Z-score was 0.5±0.7. ΔTBS Z-score was positively correlated with Δheight Z-score, Δweight Z-score and ΔBMI Z-scores, and negatively correlated height Z-score, weight Z-score and TBS Z-scores at the first DXA scan (p<0.05). Δheight Z-score, ΔBMI Z-score and the progression from early to late puberty were identified as significant independent predictors of Δlumbar BMAD Z-score (p<0.05). During two years of treatment, both BMD and TBS increased significantly. Improvement in height and in weight status, and progression in puberty are predictors of improvement in BMD and TBS.

The quantitative ultrasound method for assessing low bone mass in women with anorexia nervosa

This study investigated the potential role of quantitative ultrasound (QUS) to assess low bone mass in anorexia nervosa patients (AN). Bone parameters from QUS and DXA were positively correlated and significantly reduced in AN compared with controls, suggesting that QUS is a pertinent technique to assess low bone mass in these patients.

PURPOSE

The aim of this study was to investigate the potential role of an alternative technique, quantitative ultrasound (QUS), to assess low bone mass in patients with anorexia nervosa (AN).

METHODS

Two hundred seven young women (134 patients with AN and 73 healthy controls) with ages ranging from 14.4 to 38.4 years participated in this observational cross-sectional study. Bone mass was concomitantly evaluated by DXA to determine areal bone mineral density (aBMD; g/cm²) at hip, lumbar spine, and radius and by QUS to determine broadband ultrasound attenuation (BUA; dB/MHz) at the heel.

RESULTS

BUA (66.5 ± 4.6 dB/MHz vs 61.0 ± 5.0 dB/MHz) and aBMD at the hip (0.916 ± 0.013 g/cm² vs 0.806 ± 0.010 g/cm²), lumbar spine (0.966 ± 0.012 g/cm² vs 0.886 ± 0.010 g/cm²), and radius (0.545 ± 0.005 g/cm² vs 0.526 ± 0.04 g/cm²) were significantly decreased (p < 0.01) in patients with AN compared with controls. When patient and control data were pooled, BUA was significantly correlated with aBMD at the hip (r = 0.60, p < 0.001), lumbar spine (r = 0.48, p < 0.001), and radius (r = 0.40, p<0.001). In patients with AN, BUA and aBMD were mainly and positively correlated with weight, lean tissue mass, body mass index (BMI), and minimal BMI life and negatively with the duration of both disease and amenorrhea. Better concordance between the two techniques was obtained when absolute BUA and aBMD values were used according to the WHO T score classification.

CONCLUSION

BUA measurement at the heel by QUS appears to be a pertinent nonionizing technique to assess low bone mass in patients with AN.

Skeletal status assessment by quantitative ultrasound and bone densitometry in children with different renal conditions

Two methods of skeletal status assessment-quantitative ultrasound (QUS) and densitometry (DXA)-were applied and compared in a group of children with different renal disorders. Skeletal assessments in children with different renal conditions should rather not be based on a single diagnostic tool. Lumbar spine DXA is very effective to reveal disturbances secondary to glucocorticoids, whereas total body DXA and QUS are both better in identification of disturbances related to decreased GFR.

INTRODUCTION

The aim of the study was to evaluate the skeletal status in children in different stages of chronic kidney disease (CKD) or treated with glucocorticoids, using either densitometry (DXA) or quantitative ultrasound (QUS) methods.

METHODS

Seventy-six subjects (27 girls/49 boys) at the mean age of 11.8 ± 4.0 years were enrolled to the reported study. They were divided into three subgroups: with normal glomerular filtration rate (GFR) but treated with glucocorticoids (GCs, n = 38), with decreased GFR (CKD 2-5, n = 26) and with normal GFR and without any bone-toxic treatment (CKD 1, n = 12). DXA scans were carried out at lumbar spine (LS) and at total body (TB), and quantitative ultrasound (QUS) imaging was done at hand phalanges. QUS results were compared to those obtained from 310 healthy matched controls.

RESULTS

The average Z-score for LS-BMD and TB-BMD was below zero in all the study subgroups. Neither were there any significant differences in the mean Z-score for LS among the subgroups. The mean Z-score for TB was significantly the lowest in the CKD 2-5 subgroup. The percentage of subjects with TB Z-score ≤ - 2.0 was the highest in the CKD 2-5 subgroup (69.2%), whereas the percentage of subjects with LS Z-score ≤ - 2.0 was the highest in the GC subgroup (23.7%). QUS results in CKD 2-5 were significantly lower than those in the controls, whereas the results, obtained in GC and CKD 1 subgroups, were similar to those in healthy subjects.

CONCLUSIONS

Skeletal status assessment in children and adolescents with different renal conditions should not be based on single diagnostic approach. DXA scanning, performed at lumbar spine, is potentially more appropriate to reveal disturbances secondary to long-term GC therapy, whereas TB-DXA is highly effective in the identification of skeletal disturbances related to decreased kidney function. QUS at hand phalanges seems to be a useful diagnostic means in CKD with diminished GFR but insufficient to detect GC-related disturbances.

Bone Parameters in Anorexia Nervosa and Athletic Amenorrhea: Comparison of Two Hypothalamic Amenorrhea States

OBJECTIVE

We have reported low bone mineral density (BMD), impaired bone structure, and increased fracture risk in participants with anorexia nervosa (AN) and normal-weight oligoamenorrheic athletes (OAs). However, data directly comparing compartment-specific bone parameters in participants with AN, OAs, and controls are lacking.

DESIGN

A total of 468 female participants 14 to 21.9 years old were included: 269 with AN, 104 OAs, and 95 normal-weight eumenorrheic controls. Dual-energy x-ray absorptiometry was used to assess areal BMD (aBMD) of the whole body less head (WBLH), spine, and hip. High-resolution peripheral quantitative computed tomography was used to assess volumetric BMD (vBMD), bone geometry, and structure at the non-weight-bearing distal radius and weight-bearing distal tibia.

RESULTS

Participants with AN had lower WBLH and hip aBMD z scores than OAs and controls (P < 0.0001). Participants with AN and OAs had lower spine aBMD z scores than controls (P < 0.01). At the radius, total and cortical vBMD, percentage cortical area, and thickness were lower in the AN and OA groups than in controls (P ≤ 0.04); trabecular vBMD was lower in participants with AN than controls. At the tibia, participants with AN had lower measures for most parameters compared with OAs and controls (P < 0.05); OAs had lower cortical vBMD than controls (P = 0.002). Participants with AN and OAs had higher fracture rates than controls. Stress fracture prevalence was highest in OAs (P < 0.0001); nonstress fracture prevalence was highest in participants with AN (P < 0.05).

CONCLUSION

AN is deleterious to bone at all sites and both bone compartments. A high stress fracture rate in OAs, who have comparable WBLH and hip aBMD measures to controls, indicates that BMD in these women may need to be even higher to avoid fractures.

The Association between Weight Gain/Restoration and Bone Mineral Density in Adolescents with Anorexia Nervosa: A Systematic Review

Background: Reduced bone mineral density (BMD) is one of the most frequent medical complications of anorexia nervosa (AN). The purpose of this paper was to conduct a systematic review of the association between weight gain/restoration and BMD in adolescents with AN. Methods: Literature searches, study selection, method, and quality appraisal were performed independently by two authors, and data were collated using a narrative approach. Results: Of the 1156 articles retrieved, 19 studies met the inclusion criteria, and their analysis revealed four main findings. First, six studies reported that weight gain and restoration are associated with BMD stabilization after one year of follow-up from baseline. Second, seven studies with longer follow-up periods (≈16 months) reported significant improvements in BMD measures. Third, one study showed that normalization of BMD can be achieved after ≈30-month follow-up of normal-weight maintenance. Fourth, another study showed that male adolescents with AN who achieve weight gain but remain underweight may experience further BMD loss, unlike their weight-restored counterparts (BMI ≥ 19 kg/m²), who show a significant increase in BMD and bone mineral accrual rates that double those of healthy male adolescents. The first two findings can be considered robust, as they are supported by strong evidence. The third and fourth findings, however, derive from single studies and therefore require further confirmation. Conclusion: The literature supports weight gain as an effective strategy for promoting BMD increase in adolescents with AN. However, this process is slow, and improvements do not become detectable until ≈16-month follow-up.

State of the art systematic review of bone disease in anorexia nervosa

OBJECTIVE

Low bone mineral density (BMD) is a known consequence of anorexia nervosa (AN) and is particularly concerning during adolescence, a critical time for bone accrual. A comprehensive synthesis of available data regarding impaired bone health, its determinants, and associated management strategies in AN is currently lacking. This systematic review aims to synthesize information from key physiologic and prospective studies and trials, and provide a thorough understanding of impaired bone health in AN and its management.

METHOD

Search terms included "anorexia nervosa" AND "bone density" for the period 1995-2015, limited to articles in English. Papers were screened manually based on journal impact factor, sample size, age of participants, and inclusion of a control group. When necessary, we included seminal papers published before 1995.

RESULTS

AN leads to low BMD, impaired bone quality and increased fracture risk. Important determinants are low lean mass, hypogonadism, IGF-1 deficiency, and alterations in other hormones that impact bone health. Weight gain and menses restoration are critical for improving bone outcomes in AN. Physiologic estrogen replacement as the transdermal patch was shown to increase bone accrual in one study in adolescent females with AN; however, residual deficits persist. Bisphosphonates are potentially useful in adults with AN.

DISCUSSION

To date, evidence suggests that the safest and most effective strategy to improve bone health in AN is normalization of weight with restoration of menses. Pharmacotherapies that show promise include physiologic estradiol replacement (as the transdermal estradiol patch), and in adults, bisphosphonates. Further studies are necessary to determine the best strategies to normalize BMD in AN.

Anorexia Nervosa and Its Associated Endocrinopathy in Young People

Anorexia nervosa (AN) is a condition of severe undernutrition associated with adaptive changes in many endocrine axes. These changes include hypogonadotropic hypogonadism, acquired growth hormone resistance with low insulin-like growth factor 1 (IGF-1) levels, hypercortisolemia, altered secretion of adipokines and appetite-regulating hormones, and low bone mineral density (BMD). Bone health is impaired subsequent to a low body mass index, decreased lean mass, and the endocrine changes described above. In addition to low areal BMD, AN is characterized by a decrease in volumetric BMD, changes in bone geometry, and reductions in strength estimates, leading to an increased risk for fracture. Weight restoration is essential for restoration of normal endocrine function; however, hypercortisolemia, high peptide YY levels, and ghrelin dynamics may not completely normalize. In some patients, hypogonadotropic hypogonadism persists despite weight restoration. Weight gain and menstrual recovery are critical for improving bone health in AN; however, residual deficits may persist. Physiologic estrogen replacement using transdermal, but not oral, estrogen increases bone accrual in adolescents with AN, while bisphosphonates improve BMD in adults. Recombinant human IGF-1 and teriparatide have been used in a few studies as bone anabolic therapies. More data are necessary to determine the optimal therapeutic strategies for low BMD in AN.

Bone mineral density and body composition after laparoscopic sleeve gastrectomy in men: A short-term longitudinal study

INTRODUCTION

Longitudinal changes in bone and body composition occurring in obese men after laparoscopic sleeve gastrectomy (LSG) has been evaluated.

METHODS

In short-term longitudinal study, 25 obese men in mean baseline age 44.8 ± 10.9 years and mean body mass index (BMI) 43.3 ± 4.4 kg/m(2)were assessed after undergoing LSG for obesity. Bone mineral density (BMD) (spine, femoral neck [FN], total hip [TH], and total body [TB]) and body composition (TB bone mineral content [BMC], fat, % of fat, lean, lean BMC, total mass) were assessed at baseline, and after three and six months.

RESULTS

Mean body measurements, including weight, BMI, waist and hips, decreased significantly over the study period (p < 0.0001). FN BMD (p < 0.01) and TH BMD (p < 0.001) decreased, and spine BMD increased significantly (p < 0.001). TB BMD did not change. Weight decreased by 21.3 ± 7.3%, BMI by 21.2 ± 7.3%, FN BMD by 3.32 ± 6.35%, TH BMD by 3.51 ± 3.95% whereas spine BMD increased by 2.89 ± 5.1%. TB BMC increased by 2.4 ± 4.62%; all other variables relating to body composition decreased: fat by 33.0 ± 9.6%, lean mass by 12.8 ± 6.1%, lean BMC by 12.3 ± 5.9%, total mass by 20.1 ± 6.4%, and % fat by 15.8 ± 7.2%.

CONCLUSIONS

After LSG, body size and variables related to body composition (except for TB BMC) decreased with an accompanying decrease in FN BMD in the men in this study. Spine BMD increased, and TB BMD did not change.

Evidence-based outcomes on diagnostic accuracy of quantitative ultrasound for assessment of pediatric osteoporosis - a systematic review

BACKGROUND

Dual-energy absorptiometry (DXA) is the current reference standard for assessing pediatric osteoporosis; however due to its areal nature, it has limitations. Thus, quantitative ultrasound (QUS), a modality free of ionizing radiation, has been proposed as a potential surrogate for DXA.

OBJECTIVE

To semi-quantitatively assess the diagnostic accuracy of QUS for evaluating pediatric osteoporosis according to the U.S. Preventive Services Task Force guidelines.

MATERIALS AND METHODS

We retrieved articles on the diagnostic accuracy of quantitative US for assessing abnormal bone quality or quantity in patients of mean age ≤19 years from MEDLINE, EMBASE and Cochrane Library CCTR databases. Evidences were analyzed for reliability, construct and criterion validity, and responsiveness of quantitative US, according to the following questions: (1) How reliable is the acquisition of QUS measurements? (2) Is QUS diagnostically accurate to characterize bone strength and quality in osteoporotic children? (3) Is QUS sensitive to detect changes in bone status over time? (4) Is QUS able to predict future skeletal fractures/degeneration? Three reviewers independently evaluated the quality of reporting and methodological quality using the Standards for Reporting of Diagnostic Accuracy (STARD) and the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tools.

RESULTS

Out of 262 retrieved references (215 unique), we included 28 studies (1,963 patients; 807 reported boys and 761 girls, others unspecified; reported mean age, 0-19 years). The mean quality of reporting score was "excellent" in 24/28 (86%) studies; 11/28 (39%) studies had "adequate" research design quality.

CONCLUSION

There is no evidence of the diagnostic value of QUS at the present time despite the overall excellent and adequate research design quality of primary studies. Although QUS can produce reliable measurements, insufficient evidence has been reported to support other clinimetric properties of this technique.

Role of sclerostin and dickkopf-1 in the dramatic alteration in bone mass acquisition in adolescents and young women with recent anorexia nervosa

BACKGROUND

The nutritional deprivation of adolescent girls with anorexia nervosa (AN) reduces bone mass acquisition. A better understanding of this process would improve the medical treatment of bone alteration and its long-term consequences.

OBJECTIVE

The first aim was to model the bone mass acquisition in young women with AN. The second aim was to identify the clinical and biological factors associated with bone demineralization and investigate the potential role of sclerostin and dickkopf-1 protein (DKK-1).

POPULATION AND METHODS

Ninety-eight AN patients (mean age 18.2 ± 2.6 years) and 63 age-matched controls were enrolled in this study. Areal bone mineral density (aBMD) was determined by dual-energy x-ray absorptiometry. Calciotropic hormones, bone turnover markers, sclerostin, DKK-1, and growth factors were concomitantly evaluated.

RESULTS

The aBMD was significantly reduced at all bone sites in AN patients vs controls (range, -3.3% at the radius to -12.1% for total proximal femur). Bone formation markers IGF-1 and DKK-1 were significantly decreased in AN patients, whereas PTH, sclerostin, and the bone resorption markers were increased. In patients, the AN duration, amenorrhea, weight, body mass index, fat mass, and fat-free soft tissue were negatively correlated with aBMD, whereas the age of AN onset was positively correlated. Multiple regression analysis revealed that the duration of amenorrhea was the independent factor most negatively associated with aBMD at all bone sites except the radius.

CONCLUSION

This case-control study demonstrated a dramatic reduction in aBMD, reinforced for the first time by our models, and indicates the need for early, systematic, and adapted bone mass monitoring. Moreover, appropriate treatment should be started early in patients with AN. Increased secretion of sclerostin suggests that it may be a target for pharmacological action.

Bone mineral changes in spine and proximal femur in individual obese women after laparoscopic sleeve gastrectomy: a short-term study

BACKGROUND

The aim of the study was to establish longitudinal bone changes in obese women after laparoscopic sleeve gastrectomy (LSG).

METHODS

Twenty-nine women at baseline mean age of 40.41 ± 9.26 years and with mean body mass index (BMI) of 43.07 ± 4.99 kg/m(2) were included in a 6-month study. Skeletal status at hip [femoral neck (FN) and total hip (TH)] and spine was assessed at baseline, as well as in 3 and 6 months after surgery. Body size was measured at baseline and follow-up (weight, height, BMI, and waist).

RESULTS

Baseline body weight was 117.5 ± 18.4 kg. The mean body weight and BMI decreased by 17.9 % during the first 3 months after surgery to obtain 28.4 % after 6 months. At 6 months, BMD decreased significantly for spine by 1.24 %, FN 6.99 %, and TH 5.18 %. The changes after 3 months in individual subjects showed that, in the majority of subjects, FN and TH BMD decreased significantly (in 52 % and 69 % of subjects, respectively), and in 24 % loss of BMD was found at the spine. After 6 months, the corresponding, significant decreases in individual subjects were found in 72 %, 86 %, and 38 % of woman, respectively. Those with a significant loss of FN BMD tended to lose more weight (30 ± 9.47 versus 23.25 ± 6.08 kg, p = 0.061) than others; women with a significant decrease of FN BMD lost more weight than those with no such decrease (30.43 ± 8.07 versus 15 ± 1.91 kg).

CONCLUSION

LSG proved efficient for body weight reduction, however, with a parallel decline in bone mineral density.

RANKL/RANK/OPG system and bone status in females with anorexia nervosa

Minimal data exist concerning the relationship between osteokines of the RANKL/RANK/OPG system, especially RANKL, and bone status in females with anorexia nervosa (AN). For this reason we investigated the relationship between bone metabolism (as assessed based on serum levels of OC and CTx), and OPG and sRANKL concentrations in females with AN. Ninety-one female patients with AN and 29 healthy female subjects aged 13 to 18 years of age participated in the study. Serum OC, CTx, OPG and sRANKL were measured by ELISA. The female patients with AN demonstrated an essential suppression of OC and CTx, increased OPG and sRANKL levels, and a reduced OPG/sRANKL ratio. OC, CTx and the OPG/sRANKL ratio correlated positively with body mass and BMI in these patients, whereas in the case of OPG and sRANKL the relationship was negative. A significant positive correlation was observed between OPG and sRANKL and also between bone markers and the OPG/sRANKL ratio, and negative between CTx and sRANKL. In female patients with AN, the OPG/RANKL ratio was a significant and independent predictor of osteocalcin, a bone formation marker - OC (R(2)=0.065, p=0.012) whereas the OPG/sRANKL ratio and BMI were significant and independent predictors of a bone resorption marker - CTx (R(2)=0.095; p=0.012). In conclusion, the body mass, BMI values, and bone markers suppression observed in female patients with AN might be associated with an increase in OPG and sRANKL levels and a significant decrease of the OPG/sRANKL ratio. Although higher OPG levels may compensate for excessive bone resorption in female patients with AN, the lower OPG/sRANKL ratio seems to indicate that some inadequacies exist regarding this compensation effect, which might contribute to low bone density in these patients. The OPG/sRANKL ratio might prove a more relevant marker to predict bone metabolism in female patients with AN than sRANKL and/or OPG alone.

Bone metabolism in adolescents with anorexia nervosa

Adolescents with anorexia nervosa (AN) are at risk for low bone mass at multiple sites, associated with decreased bone turnover. Bone microarchitecture is also affected, with a decrease in bone trabecular volume and trabecular thickness, and an increase in trabecular separation. The adolescent years are typically the time when marked increases occur in bone mass accrual towards the attainment of peak bone mass, an important determinant of bone health and fracture risk in later life. AN often begins in the adolescent years, and decreased rates of bone mass accrual at this critical time are therefore also concerning for deficits in peak bone mass. Factors contributing to low bone density and decreased rates of bone accrual include alterations in body composition such as low body mass index and lean body mass, and hormonal alterations such as hypogonadism, a nutritionally acquired resistance to GH and low levels of IGF-I, relative hypercortisolemia, low levels of leptin, and increased adiponectin (for fat mass) and peptide YY. Therapeutic strategies include optimizing weight and menstrual recovery, and adequate calcium and vitamin D replacement. Oral estrogen-progesterone combination pills are not effective in increasing bone density in adolescents with AN. Recombinant human IGF-I increases levels of bone formation markers in the short term, while long-term effects remain to be determined. Bisphosphonates act by decreasing bone resorption, and are not optimal for use in adolescents with AN, in whom the primary defect is low bone formation.

5-HT and bone biology

Bone formation and bone resorption, the two processes occurring constantly and in a balanced fashion throughout the skeleton, are regulated by signals as various as local and low range growth factors, hormones, and neuronal outputs. Adding to the long list of molecules involved in these regulations, gut-derived and brain-derived serotonin were recently shown to control one or both of these processes. They do so, however, by targeting different cells, respectively acting as a hormone and as a neuromediator. Moreover, while brain serotonin positively regulates bone mass accrual peripheral serotonin is a potent inhibitor of bone formation. These findings raise the prospect that pharmacologically manipulating serotonin production could therefore become a novel strategy to treat bone loss disorders.

Bone loss in anorexia nervosa: leptin, serotonin, and the sympathetic nervous system

Anorexia nervosa (AN), a disorder characterized by the refusal to sustain a healthy weight, has the highest mortality of any psychiatric disorder. This review presents a model of AN that ties together advances in our understanding of how leptin, serotonin, and hypogonadism are brought about in AN and how they influence bone mass. Serotonin (5-hydroxytryptamine) is a key regulator of satiety and mood. The primary disturbance in AN results from alterations in serotonin signaling. AN patients suffer from serotonergic hyperactivity of Htr1a-dependent pathways that causes dysphoric mood and promotes restrictive behavior. By limiting carbohydrate ingestion, anorexics decrease their serotonin levels. Reduced serotonergic signaling in turn suppresses appetite through Htr1a/2b, decreases dysphoric mood through Htr1a/2a, and activates the sympathetic nervous system (SNS) through Htr2c receptors in the ventromedial hypothalamus. Activation of the SNS decreases bone mass through β2-adrenergic signaling in osteoblasts. Additional topics reviewed here include osteoblastic feedback of metabolism in anorexia, mechanisms whereby dietary changes exacerbate bone loss, the role of caloric restriction and Sirt1 in bone metabolism, hypothalamic hypogonadism's effects on bone mass, and potential treatments.

Bone status of children with hemophilia A assessed with quantitative ultrasound sonography (QUS) and dual energy X-ray absorptiometry (DXA)

Recent studies report reduced bone mineral density (BMD) even among young adults and children with hemophilia. Our aim was to assess bone status in children and adolescents with hemophilia with 2 methods: Quantitative UltraSonography (QUS) and Dual energy x-ray Absorptiometry (DXA), and consequently to investigate the degree of correlation between them. Twenty-seven patients (17 with severe hemophilia; residual factor activity <1% and 10 with moderate hemophilia) participated in the study. Mean age was 12.28±4.48 y (range: 4.94 to 18.00 y). All patients were evaluated with QUS at radius and at tibia and had DXA scan at lumbar spine. Anthropometric parameters were measured using standard techniques and joint evaluation was carried out using the Hemophilia Joint Health Score (HJHS). Only 2 out of 27 patients (7.5%) had BMD Z-scores <-2, whereas another 4 patients (15%) had BMD Z-scores between -1 and -2. QUS values in both radius and tibia were generally within the normal limits as only 1 patient had radius and another 1 had tibia QUS Z-score <-2. HJH scores were significantly although negatively correlated to Z-scores of tibia QUS (r=-0.455, P=0.034). No correlations were observed between lumbar BMD and radius or tibia QUS and no agreement was recorded between QUS and DXA in identifying patients at risk for osteoporosis (k=0.262). In conclusion, our study showed that only a small number of children and young adults with hemophilia have impaired bone properties as assessed both by DXA and QUS; no correlation was observed between these 2 methods.

Interpretation and application of bone turnover markers in children and adolescents

PURPOSE OF REVIEW

To assess recent research findings on various biochemical bone turnover markers and to assess their use in monitoring bone growth in children and adolescents.

RECENT FINDINGS

There are very few recent studies that investigate various serum and urine analytes that reflect bone formation and resorption to monitor bone health during longitudinal growth. In infants and young children, the measurement of bone markers in serum is suggested because of the practical difficulties associated with urine collection and by the circadian and intraindividual variation in urinary markers. During the prepubertal growth, bone turnover values are similar in age-matched boys and girls. The increase in different bone turnover markers coincides with the pubertal growth spurt. This starts later in boys and the increase in bone turnover markers also occurs later, is greater and lasts longer when compared with girls. Recent studies demonstrated that bone size increases and bone turnover decreases until mid-twenties.

SUMMARY

More than one bone formation and resorption marker should be measured to monitor longitudinal growth and bone mineral accrual, because sensitivities and predictive values of single markers are still poor. It is important to find new and more sensitive markers that could better characterize linear growth.

Assessment of serum apelin levels in girls with anorexia nervosa

CONTEXT

Pilot studies in rats have suggested that apelin (APE) is involved in the control of appetite and food intake. APE is secreted in the organs involved in the control of hunger and satiety: the stomach, hypothalamus, and fat tissue. Anorexia nervosa (AN) is an eating disorder that represents a good biological model of chronic fat tissue atrophy in humans. To date, there are no reports of APE expression in the fat tissue and its circulating concentrations in patients with AN.

OBJECTIVE

Our objective was to assess serum APE concentrations in girls with AN.

DESIGN, PARTICIPANTS, AND SETTING

APE-36 and APE-12 serum concentrations were evaluated in 87 Polish girls with restrictive AN, in 61 healthy (H) controls, 17 girls with no otherwise specified eating disorders (NOS), and 30 girls with simple obesity (OB).

RESULTS

Mean serum APE-36 and APE-12 concentrations in patients with AN and NOS were significantly lower than in the H and OB groups. However, no differences between AN, H, and NOS groups were observed when APE concentrations were calculated per body mass index (BMI). In participants with normal BMI, serum APE-36 (r = 0.35) and APE-12 (r = 0.37) concentrations correlated positively with BMI.

CONCLUSIONS

We conclude that compared with H controls, serum APE-36 and APE-12 concentrations decreased as a result of fat tissue depletion in patients with AN. Conversely, obese adolescents had elevated APE-36 and APE-12 due to excessive fat mass as well as increased APE production in adipose tissue.

Dual-energy X-ray aborptiometry assessment in children and adolescents with diseases that may affect the skeleton: the 2007 ISCD Pediatric Official Positions

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