Low trabecular bone score in adolescent female inpatients with anorexia nervosa

Trabecular Bone Score in Assessing Bone Mineralization Status in Children with End- Stage Renal Disease: A Promising Tool

Areal-bone mineral density (aBMD) of lumbar-spine dual energy X-ray absorptiometry (DXA) scan is the most frequently used tool in evaluating BMD in pediatric patients, however its size dependency have significant impact on measurements accuracy in children with chronic kidney disease (CKD). This study aimed to evaluate the usefulness of trabecular bone score (TBS) computed during lumbar-spine DXA scan in assessing bone status in children on maintenance hemodialysis (HD). Ninety-three children on HD (aged 9-18 years) were subjected to lumbar-spine DXA-scan to obtain aBMD (g/cm2) and TBS.Z-scores of aBMD for chronological-age (aBMDZ-CA), height-age (aBMDZ-HA), and TBSZ-score were calculated using mean and SD values of 442 healthy controls. aBMD and TBS were significantly lower in short-for-age and normal height-for-age patients compared to the corresponding values of controls (p < 0.05 for all). Degraded vertebral microarchitecture (TBSZ-score < -2) was detected in 48% and 44% of male and female patients respectively. There were no significant differences in median TBSZ-score between short-for-age and normal height-for-age HD patients in male (p = 0.425) and in female (p = 0.316) patients. TBSZ-score correlated significantly with aBMDZ-CA (r = 0.234; p = 0.024) but not with aBMDZ-HA (r = 0.077; p = 0.462). Patients with history of fractures (5 patients only) had significantly lower TBS scores compared to those without fracture history (p = 0.016).

CONCLUSION

TBS is significantly reduced in children on maintenance HD and is associated with increased fracture incidence. TBS has shown to be a promising tool in assessing bone quality (trabecular microarchitecture) in children with CKD being not size-dependent as is a-BMD, for further evaluation of its potential role in therapeutic and follow-up decisions.

WHAT IS KNOWN

• In children with CKD, bone demineralization starts as early as CKD stage 2, so assessment of bone health is mandatory for follow up and therapeutic decisions. • aBMD of lumbar-spine DXA scan is the most used tool in evaluating BMD in pediatric patients, however its size dependency have significant impact on measurements made in children with CKD.

WHAT IS NEW

• TBS is significantly reduced in children on maintenance HD and associated with increased fracture incidence. • TBS has shown to be a promising tool in assessing bone quality (trabecular microarchitecture) in children with CKD being not size-dependent as is a-BMD.

Trabecular Bone Score (TBS) Varies with Correction for Tissue Thickness Versus Body Mass Index: Implications When Using Pediatric Reference Norms

Trabecular bone score (TBS) derived from secondary analysis of lumbar spine dual-energy X-ray absorptiometry (DXA) scans improves fracture prediction independent of bone mineral density (BMD) in adults. The utility of TBS to assess fracture risk in younger patients has not been established because pediatric norms have been lacking. Robust TBS reference data from the Bone Mineral Density in Childhood Study (BMDCS) have been published. TBS values for the BMDCS study were derived using an algorithm that accounts for tissue thickness (TBS_TH ) rather than the commercially available algorithm that adjusts for body mass index (BMI; TBS_BMI ). We examined the magnitude of differences in TBS_TH and TBS_BMI in a cohort of 189 healthy youth. TBS values using both algorithms increased with age and pubertal development in a similar pattern. However, TBS_BMI values were systematically and significantly higher than TBS_TH (mean = 0.06, p < 0.0001). The difference between calculated TBS_BMI and TBS_TH was not uniform. Differences were greater at lower TBS values, in males, in older individuals, in those at later Tanner stages, and in those with a greater BMI Z-score. These systematic differences preclude the development of a simple formula to allow conversion of TBS_BMI to TBS_TH "equivalents." Because of these systematic differences in these two algorithms, using an individual's TBS_BMI to calculate a Z-score using the BMDCS TBS_TH reference values results in a falsely higher TBS Z-score (differences mean = 0.73, interquartile range [IQR] = 0.3 to 1.6). Until TBS_TH software for Hologic DXA equipment becomes commercially available, BMDCS TBS reference norms should not be used. © 2023 American Society for Bone and Mineral Research (ASBMR).

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.

Trabecular Bone Score Reference Values for Children and Adolescents According to Age, Sex, and Ancestry

Trabecular bone score (TBS) is used for fracture prediction in adults, but its utility in children is limited by absence of appropriate reference values. We aimed to develop reference ranges for TBS by age, sex, and population ancestry for youth ages 5 to 20 years. We also investigated the association between height, body mass index (BMI), and TBS, agreement between TBS and lumbar spine areal bone mineral density (aBMD) and bone mineral apparent density (BMAD) Z-scores, tracking of TBS Z-scores over time, and precision of TBS measurements. We performed secondary analysis of spine dual-energy X-ray absorptiometry (DXA) scans from the Bone Mineral Density in Childhood Study (BMDCS), a mixed longitudinal cohort of healthy children (n = 2014) evaluated at five US centers. TBS was derived using a dedicated TBS algorithm accounting for tissue thickness rather than BMI. TBS increased only during ages corresponding to pubertal development with an earlier increase in females than males. There were no differences in TBS between African Americans and non-African Americans. We provide sex-specific TBS reference ranges and LMS values for calculation of TBS Z-scores by age and means and SD for calculation of Z-scores by pubertal stage. TBS Z-scores were positively associated with height Z-scores at some ages. TBS Z-scores explained only 27% and 17% of the variance of spine aBMD and BMAD Z-scores. Tracking of TBS Z-scores over 6 years was lower (r = 0.47) than for aBMD or BMAD Z-scores (r = 0.74 to 0.79), and precision error of TBS (2.87%) was greater than for aBMD (0.85%) and BMAD (1.22%). In sum, TBS Z-scores provide information distinct from spine aBMD and BMAD Z-scores. Our robust reference ranges for TBS in a well-characterized pediatric cohort and precision error estimates provide essential tools for clinical assessment using TBS and determination of its value in predicting bone fragility in childhood and adolescence. © 2022 American Society for Bone and Mineral Research (ASBMR).

Abnormal Trabecular Bone Score, Lower Bone Mineral Density and Lean Mass in Young Women With Premature Ovarian Insufficiency Are Prevented by Oestrogen Replacement

BACKGROUND

Low bone density (BMD) and fractures commonly affect women with premature ovarian insufficiency (POI). However, bone microarchitecture and body composition data are lacking.

OBJECTIVE

To assess and characterise musculoskeletal phenotype and effects of oestrogen replacement therapy (ERT) in women with POI.

METHOD

Cross-sectional and longitudinal studies of 60 normal karyotype women with POI, aged 20-40 years, from 2005-2018. Dual x-ray absorptiometry (DXA)-derived spinal (LS) and femoral neck (FN) BMD, trabecular bone score (TBS), appendicular lean mass (ALM), total fat mass (TFM), and fracture prevalence were compared with 60 age-, and BMI-matched population-based controls. Longitudinal changes in bone and body composition variables and ERT effects were analysed using linear mixed models over a median duration of 6 years.

RESULTS

Women with POI were subdivided into spontaneous (s)-POI (n=25) and iatrogenic (i)-POI (n=35). Median(range) age of POI diagnosis was 34 (10-40) years with baseline DXA performed at median 1(0-13) year post-diagnosis. ERT was used by 82% women (similar for both POI groups). FN-BMD were lowest in s-POI (p<0.002). Low TBS was more common in s-POI [(44%), p=0.03], versus other groups. LS-BMD and ALM were lower in both s-POI and i-POI groups than controls (p<0.05). Fracture prevalence was not significantly different: 20% (s-POI), 17% (i-POI), and 8% (controls) (p=0.26). Longitudinal analysis of 23 POI women showed regular ERT was associated with ALM increment of 127.05 g/year (p<0.001) and protected against bone loss. However, ERT interruption was associated with annual reductions in FN BMD and TBS of 0.020g/cm² and 0.0070 (p<0.05), respectively.

CONCLUSION

Deficits in BMD, trabecular microarchitecture, and lean mass were present in women with POI. However, regular ERT protected against declines in bone variables, with an increase in ALM. Assessment of skeletal and muscle health, and advocating ERT adherence, is essential in POI to optimise musculoskeletal outcomes.

Bone health in functional hypothalamic amenorrhea: What the endocrinologist needs to know

In the original definition by Klinefelter, Albright and Griswold, the expression "hypothalamic hypoestrogenism" was used to describe functional hypothalamic amenorrhoea (FHA). Given the well-known effects of estrogens on bone, the physiopathology of skeletal fragility in this condition may appear self-explanatory. Actually, a growing body of evidence has clarified that estrogens are only part of the story. FHA occurs in eating disorders, overtraining, and during psychological or physical stress. Despite some specific characteristics which differentiate these conditions, relative energy deficiency is a common trigger that initiates the metabolic and endocrine derangements contributing to bone loss. Conversely, data on the impact of amenorrhoea on bone density or microarchitecture are controversial, and reduced bone mass is observed even in patients with preserved menstrual cycle. Consistently, oral estrogen-progestin combinations have not proven beneficial on bone density of amenorrheic women. Low bone density is a highly prevalent finding in these patients and entails an increased risk of stress or fragility fractures, and failure to achieve peak bone mass and target height in young girls. Pharmacological treatments have been studied, including androgens, insulin-like growth factor-1, bisphosphonates, denosumab, teriparatide, leptin, but none of them is currently approved for use in FHA. A timely screening for bone complications and a multidisciplinary, customized approach aiming to restore energy balance, ensure adequate protein, calcium and vitamin D intake, and reverse the detrimental metabolic-endocrine changes typical of this condition, should be the preferred approach until further studies are available.

Modestly degraded microarchitecture and high serum levels of osteopontin in Swedish females with anorexia nervosa

PURPOSE

Adult women with long-time anorexia nervosa (AN) are believed to have osteopenia (T-score ≤ 1.0) in 93 % and osteoporosis (T-score ≤ 2.5) in 38 %. Bone microarchitecture assessed by Trabecular Bone Score (TBS) predicts osteoporotic fractures. Our aim was to evaluate the microarchitecture in adult females with AN by determining TBS and to identify factors potentially associated with TBS, such as bone turnover markers.

METHODS

20 female patients with AN (DSM IV), aged 27.8 ± 4.4 years, BMI 16.6 ± 0.6 kg/m² and duration of illness of 8.5 ± 5 years had previously been evaluated with dual-energy X-ray absorptiometry (DXA). TBS measurements were now obtained, using iNsight software, from spinal DXA images. Serum levels of bone turnover markers were determined in patients and healthy normal-weight controls.

RESULTS

Compared to controls serum values of osteopontin were higher (p = 0.009). BMD in patients with AN was reduced by at least 1.0 SD at one or more skeletal sites in 65 % of patients and by at least 2.5 SD in 20 %. Only one of the patients (5%) had suffered a fracture. TBS (mean 1.35 ± 0.06; median 1.36 (1.23-1.44) was in the lower normal range (≥ 1.35). 40 % of patients showed partially (> 1.20 and < 1.35) but none showed a fully degraded micro-architecture.

CONCLUSIONS

In Swedish AN patients we found a low reduction of BMD and fracture history. The bone microarchitecture, evaluated for the first time for this group by TBS, was only modestly compromised, and to a lesser extent than expected for this group of patients with AN.

LEVEL OF EVIDENCE

Level V; cross-sectional descriptive study.

Bone mineral density at extremely low weight in patients with anorexia nervosa

OBJECTIVE

Low bone mineral density (BMD) is a frequent and invalidating consequence of chronic undernourishment in patients with anorexia nervosa (AN). The aim of this study was to assess prevalence and clinic-biological correlates of low BMD and fractures in extremely undernourished inpatients with AN.

DESIGN

Retrospective cohort study.

PATIENTS AND MEASUREMENTS

This study included 97 extremely malnourished female inpatients with AN consecutively admitted over 2 years. Clinical-biological variables, history of fractures and BMD by dual-energy X-ray absorptiometry (DXA) were examined to find predictors of low BMD and fractures.

RESULTS

The prevalence of low BMD was of 51% for lumbar spine and 38% for femoral neck. Z-scores were lower at lumbar spine (-2.2 ± 1.2 SD) than at femoral neck (-1.9 ± 0.9 SD) (P<.01). Fragility fractures were reported by 10% of patients. BMD was mainly predicted by FFM, illness duration, age at onset and restricting AN (P<.05). Fractures were predicted by sodium concentrations, femoral neck Z-score and illness duration (P<.03).

CONCLUSION

Extremely severe patients with AN have high prevalence of low BMD, predicted by severity and chronicity of malnutrition.

Bone quality assessed by trabecular bone score in severe anorexia nervosa: A brief report

OBJECTIVE

Low bone mineral density (BMD) in anorexia nervosa (AN) leads to increased risk of fractures. Debate exists whether to medicinally treat young patients with AN based on abnormal dual-energy x-ray absorptiometry (DXA) scores or to weight restore and reassess when older. Trabecular bone score (TBS), a technology measuring bone quality, is used in conjunction with DXA. This report explores the potential additional value of TBS, in adults with severe AN, to augment the DXA diagnostic information.

METHOD

Seventy-one DXA scans were reanalyzed to obtain TBS results from patients (mean age: 36.3 years). Differences in laboratory, anthropometric values and concomitant DXA measurements in relation to TBS results are reported.

RESULTS

For the cohort, mean body mass index (BMI) was 13.6 kg/m² (SD: 2.1). The vast majority of patients had normal TBS with a mean of 1.395 (SD: 0.08) but, most patients (69%) had abnormal average DXA BMD Z-scores of -2.2 (SD: 1.2). The patients who also demonstrated degraded bone quality on TBS had significantly lower percent ideal body weight and elevated alkaline phosphatase compared to patients with normal TBS (p's < .05).

DISCUSSION

Low BMD treatment decisions in AN may be optimized by considering both DXA and TBS results.

Effects of age at estrogen replacement therapy initiation on trabecular bone score in Japanese adults with Turner syndrome

The effects of the age at estrogen replacement therapy (ERT) initiation on bone quality in Turner syndrome were evaluated using trabecular bone score. Early puberty ERT positively correlated with increase in bone quality. Early initiation of ERT is necessary for the acquisition of bone quality as well as bone density.

INTRODUCTION

Studies have reported associations between bone mineral density and estrogen replacement therapy (ERT) in Turner syndrome (TS) patients; however, few studies exist on the effect on bone quality. The aim of this study was to evaluate the effects of the age at ERT initiation on bone quality of Japanese TS patients, cross-sectionally and longitudinally.

METHODS

Cross-sectionally, 95 TS patients were divided into three groups based on their age at initiation of ERT: A (12-14 years, 11 patients), B (15-17 years, 47 patients), and C (over 18 years, 37 patients). To assess bone quality, trabecular bone score (TBS) was used. The effects of age at initiation and duration of ERT on TBS were examined using multiple regression analysis. In the longitudinal study, 48 patients who underwent dual-energy X-ray absorptiometry multiple times were divided into three groups: D (12-14 years, 8 patients), E (15-17 years, 18 patients), and F (over 18 years, 22 patients). Each group was analyzed for the rate of change in TBS per year.

RESULTS

Cross-sectionally, the TBS showed significant differences among the three groups (TBS A, 1.302; B, 1.299; C, 1.245) (p = 0.013); group C was significantly lower than B (p = 0.014); bone quality was degraded. Multiple regression analysis revealed that age at ERT initiation significantly affected the increase in TBS (p = 0.002). Longitudinally, the rate of change of TBS was not significantly different in the three groups (p = 0.73).

CONCLUSION

Early initiation of ERT may have positive effects on bone quality in TS. Large prospective studies will be needed.

Trabecular Bone Score in Children and Adolescents With Inflammatory Bowel Diseases

INTRODUCTION

Trabecular bone score (TBS) is a textural index that evaluates bone microarchitecture of the lumbar spine. Our aim was to assess TBS in children with inflammatory bowel diseases and to evaluate correlations with clinical, laboratory and densitometric variables.

METHODS

A retrospective study of TBS and areal bone mineral density measurements by dual-energy X-ray absorptiometry (DXA) of children with either Crohn's disease (CD) or ulcerative colitis (UC). Bone mineral apparent density was calculated for size adjustment. TBS Z-score for each child were calculated based on data from a healthy population of similar age and gender distribution. Variables significantly associated with TBS were included in stepwise linear regression models to examine independent predictors of TBS.

RESULTS

Fifty patients (age at DXA scan 13.8 ± 3.0 years, 29 males) were included. No significant differences were observed between the patients with CD and UC, in age at diagnosis, age at DXA scan and disease duration. The mean TBS of patients with CD (n = 35) was lower than of patients with UC (n = 15): 1.340 ± 0.080 vs 1.395 ± 0.092, p = 0.040. The mean TBS Z-score of patients with CD, -0.443 ± 0.788, was significantly lower than expected in healthy children (p = 0.002), while the mean TBS Z-score of patients with UC, 0.231 ± 0.685, was similar to that of healthy children (p = 0.212). In the stepwise linear regression analysis, BMI Z-score at diagnosis, phosphorus level at diagnosis and age at the time of the DXA scan were significant independent predictors of TBS (r² = 0.604; β = 0.037, 95% confidence interval (CI) for β 0.022-0.051, p < 0.001; β = 0.045, 95% CI: 0.017-0.073, p = 0.002; and β = 0.031, 95% CI: 0.005-0.021, p < 0.002, respectively).

CONCLUSIONS

TBS is significantly reduced in pediatric patients with CD but not in patients with UC. This finding likely reflects the effect of CD on bone microarchitecture.

Bone Microarchitecture Assessed by Trabecular Bone Score Is Independent of Mobility Level or Height in Pediatric Patients with Cerebral Palsy

Bone strength and fracture risk do not only depend on bone density, but also on bone structure. The trabecular bone score (TBS) evaluates homogeneity of bone microarchitecture indirectly by measuring gray-level variations of two-dimensional (2D) DXA images. Although TBS is well-established for adults, there have been only few publications in pediatrics. In this monocentric retrospective analysis, we investigated TBS in children and adolescents with cerebral palsy (CP), a patient group vulnerable to low bone mineral mass due to impaired mobility. The influence of different parameters on TBS and areal BMD (aBMD) were evaluated, as well as the relationship between TBS and aBMD. We compared TBS values of our study population to a reference population. A total of 472 lumbar spine-dual-energy X-ray absorptiometry (LS-DXA) scans of children and adolescents with CP (205 female), aged between 4 and 18 years, were analyzed. The DXA-scans were part of the routine examination. The children had no records of fractures or specific bone diseases. Our study population with CP had similar TBS as the reference population. TBS did not increase with age until an inflection point at 10 years in females, and 12 years in males. Girls had significantly higher TBS than boys (p = .049) and pubertal girls aged 8 to 13 years had significantly higher TBS than prepubertal girls (p = .009). TBS standard deviation score for age (SDS-TBS) and aBMD Z-scores correlated weakly (p < .001; R = 0.276 [males], R = 0.284 [females]). Other than for aBMD Z-scores, SDS-TBS was not influenced by age-adjusted height Z-scores and there was no significant difference in SDS-TBS when grouped by mobility levels, using the Gross Motor Function Classification System (GMFCS). Our results indicate that children with CP have a similar homogeneous distribution of trabecular microarchitecture as controls. Puberty initiation appears to be essential for increase of TBS with age and for sex differences. TBS seems less influenced by body composition, height, and mobility than aBMD. © 2020 The Authors. Journal of Bone and Mineral Research published by American Society for Bone and Mineral Research.