The Determinants of Peak Bone Mass

Changes in Sex Steroids and Enteric Peptides After Sleeve Gastrectomy in Youth in Relation to Changes in Bone Parameters

CONTEXT

Sleeve gastrectomy (SG) improves metabolic endpoints but is associated with impaired bone outcomes.

OBJECTIVE

To determine mechanisms contributing to impaired bone health in youth following SG.

METHODS

12-month longitudinal observational study in a multidisciplinary tertiary-care hospital, including 64 youth 13-25 years old with moderate-to-severe obesity (51 females); 30 underwent SG and 34 were nonsurgical (NS) controls. SG was undertaken after a combined decision-making process between treatment team and patient. The main outcome measures were fasting blood for enteric peptides, sex steroids, sclerostin, and bone turnover markers (N-terminal propeptide of type 1 procollagen [P1NP] and C-terminal cross-linking telopeptide [CTX]); dual-energy X-ray absorptiometry measures of areal bone mineral density (aBMD) and body composition; high resolution peripheral quantitative computed tomography; measures of volumetric BMD (vBMD); microfinite element analysis of strength estimates (distal radius and tibia).

RESULTS

SG had greater reductions in body mass index (BMI) z-scores, serum estrone, and the free androgen index (FAI) (P ≤ .046), and greater increases in sclerostin, P1NP, and CTX (P ≤ .010) than NS controls. Fasting ghrelin decreased in SG vs NS (P < .0001); fasting peptide YY did not change. Most changes were driven by female SG participants. Among females (the majority of study participants), after controlling for baseline age and race, reductions in total hip aBMD Z-scores were positively associated with changes in BMI, lean mass, estrone, FAI, and ghrelin, and inversely with changes in sclerostin.. Decreases in total vBMD of the radius and tibia were associated positively with decreases in BMI. Increases in CTX were associated with decreases in BMI, lean mass, and ghrelin, and increases in sclerostin.

CONCLUSION

Bone loss after SG in youth is associated with changes in body composition, sex steroids, sclerostin, and enteric peptides. These are potential targets for future preventative or therapeutic strategies.

Serum PFAS and Urinary Phthalate Biomarker Concentrations and Bone Mineral Density in 12-19 Year Olds: 2011-2016 NHANES

CONTEXT

Per- and polyfluoroalkyl substances (PFAS) and phthalates are 2 families of environmental endocrine disruptors that may be associated with areal lower bone mineral density (aBMD).

OBJECTIVE

To examine associations between serum PFAS and urinary phthalate biomarker concentrations and their mixtures with aBMD Z-scores in adolescents.

DESIGN, PATIENTS, AND MEASURES

We examined serial cross-sectional data from male (n = 453) and female (n = 395) 12- to 19-year-old participants in the 2011 through 2016 National Health and Nutrition Examination Survey with measures of serum PFAS, urinary phthalate metabolites, and dual-energy X-ray absorptiometry aBMD Z-scores (total body less head). In sex-specific models, we used linear regression to examine associations of individual PFAS and phthalate biomarkers with aBMD Z-scores, and Bayesian kernel machine regression to examine the association of the overall PFAS/phthalate biomarker mixture with aBMD Z-scores. We replicated the analysis, stratifying by race/ethnicity.

RESULTS

Participants were (mean ± SD) 15 ± 2.1 years of age. In males, each doubling of serum perfluorooctanoate (PFOA), perfluorooctane sulfonate, urinary mono-isobutyl phthalate (MiBP), mono-n-butyl phthalate, and the overall PFAS/phthalate mixture was associated with a lower aBMD Z-score (eg, for PFOA: -0.24; 95% CI, -0.41 to -0.06). Serum PFOA and urinary MiBP were associated with higher aBMD Z-scores in females (eg, for PFOA: 0.09; 95% CI, -0.07 to 0.25). Findings did not differ by race/ethnicity.

CONCLUSIONS

Certain PFAS and phthalates may be associated with reduced bone mineral density in adolescent males. Bone mineral density tracks across the life course, so if replicated in longitudinal cohorts, this finding may have implications for lifelong skeletal health.

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

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

Dietary Complex and Slow Digestive Carbohydrates Promote Bone Mass and Improve Bone Microarchitecture during Catch-Up Growth in Rats

Catch-up growth is a process that promotes weight and height gains to recover normal growth patterns after a transient period of growth inhibition. Accelerated infant growth is associated with reduced bone mass and quality characterized by poor bone mineral density (BMD), content (BMC), and impaired microarchitecture. The present study evaluated the effects of a diet containing slow (SDC) or rapid (RDC) digestible carbohydrates on bone quality parameters during the catch-up growth period in a model of diet-induced stunted rats. The food restriction period negatively impacted BMD, BMC, and microarchitecture of appendicular and axial bones. The SDC diet was shown to improve BMD and BMC of appendicular and axial bones after a four-week refeeding period in comparison with the RDC diet. In the same line, the micro-CT analysis revealed that the trabecular microarchitecture of tibiae and vertebrae was positively impacted by the dietary intervention with SDC compared to RDC. Furthermore, features of the cortical microstructure of vertebra bones were also improved in the SDC group animals. Similarly, animals allocated to the SDC diet displayed modest improvements in growth plate thickness, surface, and volume compared to the RDC group. Diets containing the described SDC blend might contribute to an adequate bone formation during catch-up growth thus increasing peak bone mass, which could be linked to reduced fracture risk later in life in individuals undergoing transient undernutrition during early life.

The microbiome: A heritable contributor to bone morphology?

Bone provides structure to the vertebrate body that allows for movement and mechanical stimuli that enable and the proper development of neighboring organs. Bone morphology and density is also highly heritable. In humans, heritability of bone mineral density has been estimated to be 50-80%. However, genome wide association studies have so far explained only 25% of the variation in bone mineral density, suggesting that a substantial portion of the heritability of bone mineral density may be due to environmental factors. Here we explore the idea that the gut microbiome is a heritable environmental factor that contributes to bone morphology and density. The vertebrae skeleton has evolved over the past ~500 million years in the presence of commensal microbial communities. The composition of the commensal microbial communities has co-evolved with the hosts resulting in species-specific microbial populations associated with vertebrate phylogeny. Furthermore, a substantial portion of the gut microbiome is acquired through familial transfer. Recent studies suggest that the gut microbiome also influences postnatal development. Here we review studies from the past decade in mice that have shown that the presence of the gut microbiome can influence postnatal bone growth regulating bone morphology and density. These studies indicate that the presence of the gut microbiome may increase longitudinal bone growth and appositional bone growth, resulting differences cortical bone morphology in long bones. More surprising, however are recent studies showing that transfer of the gut microbiota among inbred mouse strains with distinct bone phenotypes can alter postnatal development and adult bone morphology. Together these studies support the concept that the gut microbiome is a contributor to skeletal phenotype.

Osteoporosis in children and adolescents: when to suspect and how to diagnose it

Early recognition of osteoporosis in children and adolescents is important in order to establish an appropriate diagnosis of the underlying condition and to initiate treatment if necessary. In this review, we present the diagnostic work-up, and its pitfalls, of pediatric patients suspected of osteoporosis including a careful collection of the medical and personal history, a complete physical examination, biochemical data, molecular genetics, and imaging techniques. The most recent and relevant literature has been reviewed to offer a broad overview on the topic. Genetic and acquired pediatric bone disorders are relatively common and cause substantial morbidity. In recent years, there has been significant progress in the understanding of the genetic and molecular mechanistic basis of bone fragility and in the identification of acquired causes of osteoporosis in children. Specifically, drugs that can negatively impact bone health (e.g. steroids) and immobilization related to acute and chronic diseases (e.g. Duchenne muscular dystrophy) represent major risk factors for the development of secondary osteoporosis and therefore an indication to screen for bone mineral density and vertebral fractures. Long-term studies in children chronically treated with steroids have resulted in the development of systematic approaches to diagnose and manage pediatric osteoporosis.

CONCLUSIONS

Osteoporosis in children requires consultation with and/or referral to a pediatric bone specialist. This is particularly relevant since children possess the unique ability for spontaneous and medication-assisted recovery, including reshaping of vertebral fractures. As such, pediatricians have an opportunity to improve bone mass accrual and musculoskeletal health in osteoporotic children.

WHAT IS KNOWN

• Both genetic and acquired pediatric disorders can compromise bone health and predispose to fractures early in life. • The identification of children at risk of osteoporosis is essential to make a timely diagnosis and start the treatment, if necessary.

WHAT IS NEW

• Pediatricians have an opportunity to improve bone mass accrual and musculoskeletal health in osteoporotic children and children at risk of osteoporosis. • We offer an extensive but concise overview about the risk factors for osteoporosis and the diagnostic work-up (and its pitfalls) of pediatric patients suspected of osteoporosis.

Low bone mass in Noonan syndrome children correlates with decreased muscle mass and low IGF-1 levels

Although musculoskeletal abnormalities have long been described in patients with Noonan syndrome (NS), only a few studies have investigated the bone status of these patients. The aim of this retrospective observational study was to describe the bone health of children with NS. Thirty-five patients with a genetically confirmed diagnosis of NS were enrolled. We analyzed the axial skeleton (lumbar spine) using dual energy X-ray absorptiometry and the appendicular skeleton (hand) with the BoneXpert system. Bone metabolism markers, including mineral homeostasis parameters, serum 25-hydroxy vitamin D (25-OHD) levels and markers of bone formation and resorption were also reported. Compared to the general population, axial and appendicular bone mass was significantly decreased in children with NS (p < 0.0001). Serum 25-OHD levels were low in about half of the patients and were negatively correlated with age (r = -0.52; p < 0.0001). Patients with NS exhibited reduced bone formation marker levels and increased bone resorption marker levels (p < 0.0001). No gender difference or genotype-phenotype correlations were found for the different bone parameters. Muscle mass and, to a lesser extent, serum insulin-like growth factor 1 (IGF-1) levels were independent predictors of whole-body bone mineral content (p < 0.0001 for both parameters; adjusted R² = 0.97). In conclusion, bone mass is reduced in children with NS and correlates with decreased muscle mass and low serum IGF-1 levels. These data justify addressing all potential threats to bone health including sufficient calcium and vitamin D intake, regular physical exercise, and hormone replacement therapy.

The effect of impact exercise on bone mineral density: A longitudinal study on non-athlete adolescents

PURPOSE

High impact exercise is known to induce osteogenic effects in the skeleton. However, less is known about the systemic effect of exercise practice in a potential adaptive mechanism of the skeletal accrual. This research aimed to assess the effect of impact exercise on bone mineral density (BMD) in the radius throughout adolescence.

METHODS

This study evaluated 1137 adolescents, at 13 and 17 years old, as part of the population-based cohort EPITeen. BMD (g/cm²) was measured at the ultradistal and proximal radius of the non-dominant forearm by dual-energy X-ray absorptiometry (DXA) using a Lunar® Peripheral Instantaneous X-ray Image device. The practice of (extra-curricular) exercise was categorized as: no exercise, exercise with high impact and exercise with low impact. Regression coefficients (β) and respective 95% confidence intervals (CI_95%) were used to estimate the association between exercise practice categories at 13 years old and BMD at 13 and 17 years old and BMD gain between evaluations.

RESULTS

In boys, at 13 years, BMD was similar between the ones not practicing exercise and those practicing exercise with low impact, and the gain of BMD was also similar in both groups. Still in boys, at 13 years, those who practiced exercise with high impact presented higher mean (standard-deviation) of BMD, comparing to the other two groups (no exercise and low impact exercise), and also significantly increased the BMD gain between 13 and 17 years (β = 0.013; CI_95%0.003;0.023). In girls, no statistically significant differences on BMD were found between the categories of exercise at 13 years and BMD at 17 years of age.

CONCLUSION

This research shows that the practice of high impact exercise could help to increase BMD more than low impact exercise even in a nonweight-bearing bone during adolescence.

Musculoskeletal Microbiology: The Microbiome in Orthopaedic Biomechanics

Orthopaedic biomechanics and bioengineering is a founding discipline of biomedical engineering that focuses on the effects of mechanical stress and strain on musculoskeletal tissues during growth, function and repair. In the past decade the gut microbiome has emerged as a contributor to disease processes throughout the body, but only recently has been shown to influence orthopaedic biomechanics. Here I review emergent findings showing that the gut microbiome can regulate important aspects of the musculoskeletal system including growth and development; tissue failure and disease; and orthopaedic surgery. These early findings suggest that the microbiome may help answer questions in orthopaedic biomechanics that are not well addressed by current interventions, and highlights the promise of the emerging field of "Musculoskeletal Microbiology".

Bone mineral density surveillance for childhood, adolescent, and young adult cancer survivors: evidence-based recommendations from the International Late Effects of Childhood Cancer Guideline Harmonization Group

Childhood, adolescent, and young adult cancer survivors are at increased risk of reduced bone mineral density. Clinical practice surveillance guidelines are important for timely diagnosis and treatment of these survivors, which could improve bone mineral density parameters and prevent fragility fractures. Discordances across current late effects guidelines necessitated international harmonisation of recommendations for bone mineral density surveillance. The International Late Effects of Childhood Cancer Guideline Harmonization Group therefore established a panel of 36 experts from ten countries, representing a range of relevant medical specialties. The evidence of risk factors for very low and low bone mineral density and fractures, surveillance modality, timing of bone mineral density surveillance, and treatment of very low and low bone mineral density were evaluated and critically appraised, and harmonised recommendations for childhood, adolescent, and young adult cancer survivors were formulated. We graded the recommendations based on the quality of evidence and balance between potential benefits and harms. Bone mineral density surveillance is recommended for survivors treated with cranial or craniospinal radiotherapy and is reasonable for survivors treated with total body irradiation. Due to insufficient evidence, no recommendation can be formulated for or against bone mineral density surveillance for survivors treated with corticosteroids. This surveillance decision should be made by the survivor and health-care provider together, after careful consideration of the potential harms and benefits and additional risk factors. We recommend to carry out bone mineral density surveillance using dual-energy x-ray absorptiometry at entry into long-term follow-up, and if normal (Z-score > -1), repeat when the survivor is aged 25 years. Between these measurements and thereafter, surveillance should be done as clinically indicated. These recommendations facilitate evidence-based care for childhood, adolescent, and young adult cancer survivors internationally.

Impact of sleeve gastrectomy on bone outcomes in adolescents vs. adults with obesity

BACKGROUND

Sleeve gastrectomy (SG) is the most common metabolic and bariatric surgery (MBS) procedure in adolescents and adults. Only few studies have assessed bone outcomes following SG and it is unknown whether skeletal changes differ by age group. Recent studies have identified marrow adipose tissue (MAT) as a novel biomarker for bone quality with studies in adults showing high MAT in those with visceral adiposity and a reciprocal increase in MAT with bone loss.

OBJECTIVE

To determine the impact of SG on volumetric BMD (vBMD) and MAT in adolescents and adults with obesity. We hypothesized that SG would lead to a decrease in vBMD and increase in MAT but that these changes would be less pronounced in adolescents compared to adults.

MATERIALS AND METHODS

The study was IRB-approved and HIPAA-compliant. Written informed consent/assent was obtained. We examined 10 adolescents (mean age 17.8 ± 2.5 years, mean BMI 43.5 ± 5.6 kg/m²) and 10 sex, race, and BMI-matched adults (mean age 49.5 ± 13.6 years, mean BMI 43.7 ± 5.9 kg/m²), before and 12 months after SG. At baseline and 12 months, subjects underwent quantitative CT of the lumbar spine (L1-L2) to assess trabecular vBMD, single voxel proton MR spectroscopy at 3 T (PRESS pulse sequence without water suppression) at L1-L2 to quantify MAT, and MRI of the abdomen to assess visceral (VAT) and subcutaneous adipose tissue (SAT).

RESULTS

At baseline, adolescents had lower MAT (p = 0.0002) and higher vBMD (p = 0.050) compared to adults. Adolescents and adults lost 27.9 ± 6.5 vs. 25.0 ± 11.2% of body weight (p < 0.0001 for within group change), while there was no significant difference between groups (p = 0.455). There was a significant reduction in vBMD in adults (-3.9 ± 3.9%, p = 0.005) and a trend for a reduction in adolescents (-3.7 ± 7.5%, p = 0.119), with no significant difference between groups (p = 0.944). Lumbar MAT content increased in both adults and adolescents (p ≤ 0.034), while the difference was not significant between groups (p = 0.281). In adolescents and adults, 12-month percent change in weight and BMI was positively associated with % change in MAT (p ≤ 0.042). 12-month percent change in MAT was positively associated with 12-month % change in SAT in adolescents and 12-month percent change in VAT in adults (p ≤ 0.045).

CONCLUSION

SG in adolescents and adults with severe obesity is associated with a reduction in lumbar vBMD and an increase in lumbar MAT, although the reduction in adolescents did not reach statistical significance, with no significant differences in these endpoints between groups. Our results suggest detrimental effects of bariatric surgery on bone for patients across the life span.

Long-Term Administration of Abacavir and Etravirine Impairs Semen Quality and Alters Redox System and Bone Metabolism in Growing Male Wistar Rats

Highly active antiretroviral therapy (HAART) is used in HIV-infected patients. Alongside the prolongation of patients' life, adverse side effects associated with long-term therapy are becoming an increasing problem. Therefore, optimizing of HAART is extremely important. The study is aimed at evaluating the toxicity of abacavir and etravirine in monotherapy on the reproductive system, liver, kidneys, and bones in young, sexually mature, male rats. Thirty-six 8-week-old male Wistar rats randomized into three 12-animal groups received either normal saline (control), abacavir 60 mg/kg (AB group), or etravirine 40 mg/kg (ET group) once daily for 16 weeks. Semen morphology, oxide-redox state parameters (MDA, SOD, catalase, GPx, glutathione, GSH/GSSG ratio) in tissue homogenates (testes, liver, kidneys), and serum samples were studied. In bones, microcomputed tomography and a four-point bending test were performed. Total sperm count, sperm concentration, motility, and sperm morphology did not differ significantly in AB or ET groups compared to the control. In the flow cytometry of semen, an increased percentage of cells with denatured DNA was noticed for both tested drugs. However, no significant changes of oxide-redox state in testicular homogenates were found, except of increased SOD activity in the AB-receiving group. Additionally, ET significantly altered catalase and GPx in the liver and SOD activity in kidneys. Abacavir decreased catalase in the liver and GSH levels in kidneys. AB caused significant changes to bone microarchitecture (bone volume fraction, trabecular number, connectivity density, total porosity) and increased Young's modulus. Etravirine had a greater impact on macrometric parameters of bones (tibial index, mid-tibial diameter, femur length). After 4 weeks in the ET group, a lower 1,25-dihydroxyvitamin D₃ serum concentration was found. The results showed that abacavir and etravirine disturb oxidative stress. An increase in the percentage of sperms with chromatin damage suggests decreased fertility in rats receiving the studied drugs. Both drugs affected bone formation in growing rats. Additionally, etravirine disturbed vitamin D metabolism.

Current Perspectives on the Beneficial Effects of Soybean Isoflavones and Their Metabolites for Humans

Soybeans are rich in proteins and lipids and have become a staple part of the human diet. Besides their nutritional excellence, they have also been shown to contain various functional components, including isoflavones, and have consequently received increasing attention as a functional food item. Isoflavones are structurally similar to 17-β-estradiol and bind to estrogen receptors (ERα and ERβ). The estrogenic activity of isoflavones ranges from a hundredth to a thousandth of that of estrogen itself. Isoflavones play a role in regulating the effects of estrogen in the human body, depending on the situation. Thus, when estrogen is insufficient, isoflavones perform the functions of estrogen, and when estrogen is excessive, isoflavones block the estrogen receptors to which estrogen binds, thus acting as an estrogen antagonist. In particular, estrogen antagonistic activity is important in the breast, endometrium, and prostate, and such antagonistic activity suppresses cancer occurrence. Genistein, an isoflavone, has cancer-suppressing effects on estrogen receptor-positive (ER+) cancers, including breast cancer. It suppresses the function of enzymes such as tyrosine protein kinase, mitogen-activated kinase, and DNA polymerase II, thus inhibiting cell proliferation and inducing apoptosis. Genistein is the most biologically active and potent isoflavone candidate for cancer prevention. Furthermore, among the various physiological functions of isoflavones, they are best known for their antioxidant activities. S-Equol, a metabolite of genistein and daidzein, has strong antioxidative effects; however, the ability to metabolize daidzein into S-equol varies based on racial and individual differences. The antioxidant activity of isoflavones may be effective in preventing dementia by inhibiting the phosphorylation of Alzheimer's-related tau proteins. Genistein also reduces allergic responses by limiting the expression of mast cell IgE receptors, which are involved in allergic responses. In addition, they have been known to prevent and treat various diseases, including cardiovascular diseases, metabolic syndromes, osteoporosis, diabetes, brain-related diseases, high blood pressure, hyperlipidemia, obesity, and inflammation. Further, it also has positive effects on menstrual irregularity in non-menopausal women and relieving menopausal symptoms in middle-aged women. Recently, soybean consumption has shown steep increasing trend in Western countries where the intake was previously only 1/20-1/50 of that in Asian countries. In this review, I have dealt with the latest research trends that have shown substantial interest in the biological efficacy of isoflavones in humans and plants, and their related mechanisms.

Sexual Dimorphism in Differentiating Osteoclast Precursors Demonstrates Enhanced Inflammatory Pathway Activation in Female Cells

Sexual dimorphism of the skeleton is well documented. At maturity, the male skeleton is typically larger and has a higher bone density than the female skeleton. However, the underlying mechanisms for these differences are not completely understood. In this study, we examined sexual dimorphism in the formation of osteoclasts between cells from female and male mice. We found that the number of osteoclasts in bones was greater in females. Similarly, in vitro osteoclast differentiation was accelerated in female osteoclast precursor (OCP) cells. To further characterize sex differences between female and male osteoclasts, we performed gene expression profiling of cultured, highly purified, murine bone marrow OCPs that had been treated for 3 days with macrophage colony-stimulating factor (M-CSF) and receptor activator of NF-κB ligand (RANKL). We found that 125 genes were differentially regulated in a sex-dependent manner. In addition to genes that are contained on sex chromosomes, transcriptional sexual dimorphism was found to be mediated by genes involved in innate immune and inflammatory response pathways. Furthermore, the NF-κB-NFATc1 axis was activated earlier in female differentiating OCPs, which partially explains the differences in transcriptomic sexual dimorphism in these cells. Collectively, these findings identify multigenic sex-dependent intrinsic difference in differentiating OCPs, which results from an altered response to osteoclastogenic stimulation. In humans, these differences could contribute to the lower peak bone mass and increased risk of osteoporosis that females demonstrate relative to males. © 2021 American Society for Bone and Mineral Research (ASBMR).

Validity of New Technologies That Measure Bone-Related Dietary and Physical Activity Risk Factors in Adolescents and Young Adults: A Scoping Review

New technologies may improve the validity of dietary and physical activity assessment and thereby associated findings for lifestyle-related bone health research. This scoping review mapped the evidence for the validity of new technologies that measure bone-related dietary and physical activity risk factors in adolescents and young adults. A systematic literature search was conducted using seven electronic databases for peer-reviewed studies published from January 2008 to 2021. Four studies from four countries were deemed eligible and included in the qualitative synthesis for this review. Two studies assessed diet, reporting the validity or usability of apps. Apps were shown to be a valid tool to measure the dietary intake of vitamin D (r = 0.84) and calcium (r = 0.63). Two studies assessed physical activity and reported the validity of wearable devices to measure impact loading. Hip-worn raw acceleration output correlated positively with ground reaction forces (GRF) for both studies (r range = 0.50-0.87), but wrist-worn accelerations and loading outcomes differed between studies, reporting poor to strong correlations (r range = 0.17-0.87). More research to provide robust evidence concerning validity, reliability, usability and engagement for the use of newer technologies is needed for future diet and physical activity bone research.

Fracture Rates and Fracture Risk in Patients With Marfan Syndrome: A Nationwide Register-Based Cohort Study

Marfan syndrome (MFS), a rare genetic disease, has a prevalence of 6.5 in 100,000. Studies show that patients with MFS have reduced areal bone mineral density (BMD) compared with non-MFS individuals. We have previously shown that patients with MFS have reduced volumetric BMD and compromised trabecular and cortical bone microarchitecture. The present study was a registry-based, nationwide, population-based, cohort study using register data, aimed to evaluate fracture risk and fracture rates in MFS. We included 406 (196 women) patients with MFS through the Danish National Patient Register and 40,724 (19,327 women) persons, randomly selected and matched from the Civil Registry System. A total of 21.9% of the MFS and 18.9% of the reference population had experienced at least one fracture from 1995 to 2018. The fracture incidence rate was 27.5 per 1000 person-years in the MFS cohort (highest in young men and old women with MFS), and 20.3 per 1000 person-years in the reference population. The overall incidence rate ratio between the MFS and the reference population was 1.35 (95% confidence interval [CI ] 1.18-1.55) for all fractures. When evaluating the risk of being registered with an osteoporosis diagnosis in the Danish National Patient Register, starting relevant treatment for osteoporosis or experiencing a hip or spine fracture, 10.3% of the MFS cohort and 3.3% of the reference population could be classified as being osteoporotic. The between-group subhazard ratio was 3.97 (95% CI 2.56-6.25). Patients with MFS started treatment with an antiosteoporotic drug at a younger age than the reference population (57 [interquartile range 55-67] versus 71 [63-73]) years. The life expectancy in MFS is increasing, resulting in more patients facing diseases that are related to old age, such as age-related bone loss and increased risk of fractures. Our data suggest that bone health and fracture prevention needs to be part of the standard care for patients with MFS. © 2021 American Society for Bone and Mineral Research (ASBMR).

Milk and Dairy Products: Good or Bad for Human Bone? Practical Dietary Recommendations for the Prevention and Management of Osteoporosis

Osteoporosis affects women twice as often as men. Additionally, it is estimated that 0.3 million and 1.7 million people have hip fractures in the USA and Europe, respectively. Having a proper peak bone mass and keeping it as long as possible is especially important for osteoporosis prevention. One of the most important calcium sources is milk and dairy products. Breast milk is the best infant food, but milk should not be avoided later in life to prevent losing bone mass. On the other hand, more and more people limit their milk consumption and consume other dairy or non-dairy products. For example, they are usually replaced with plant beverages, which should be consumed carefully in several age groups. Additionally, an important element of milk and dairy products, as well as plant beverages, are probiotics and prebiotics, which may modulate bone turnover. Dietary recommendations focused on milk, and dairy products are an important element for the prevention of osteoporosis.

A long-term trajectory of bone mineral density in childhood cancer survivors after discontinuation of treatment: retrospective cohort study

Low bone mineral density (BMD) was diagnosed in 24% of childhood cancer survivors (CCS), whereas very low BMD was relatively uncommon at 8%. We suggest that low BMD in CCS may become alleviated over time. Stem cell transplantation, radiotherapy, and underweight were the strongest independent predictors of decreased BMD.

PURPOSE

Childhood cancer survivors (CCS) are at risk of premature bone loss, although published studies are inconsistent. The objective of this study was to evaluate the prevalence and pattern of low bone mineral density (BMD) in short- and long-term CCS, and to determine clinical factors affecting skeleton after anticancer treatment.

METHODS

This retrospective study was conducted in a cohort of 326 children and young adult CCS (147 females) who completed anticancer treatment. BMD was determined by dual-energy X-ray absorptiometry (DXA). Low BMD was defined as a Z-score ≤ - 1.0, and the very low BMD as a Z-score ≤ - 2.0. Additionally, the changes in BMD over time were studied in 123 CCS who had been re-examined by DXA during follow-up.

RESULTS

Median age at diagnosis was 7.27 years (range, 4.4-10.6); median time between end of treatment and DXA was 6.12 (range, 4.0-22.0). Low BMD was found in 24% of CCS, while very low BMD was relatively uncommon (8%). Based on multivariate analysis, the following were significantly associated with low BMD at the follow-up: hematopoietic stem cell transplantation (OR 3.13, 95% CI 1.02-9.63), head and neck radiotherapy (OR 2.54, 95% CI 1.32-4.90), and body weight below the standard reference (OR 3.57, 95% CI 1.24-10.23). The time-related trajectory showed an improvement (BMD_LS) or stabilization (BMD_TB) in Z-scores values.

CONCLUSION

These data based on serial DXA measurements, encompassing a long-lasting observation period, show that CCS may not be at risk of premature bone loss in young adulthood. However, it is unknown how the scenario for skeletal mass is until the CCS will achieve older or postmenopausal age.

Immune Markers and Their Association with Bone Density in Children, Adolescents, and Young Adults with Perinatally Acquired HIV

To describe distributions of immune markers in children and young adults by sex and HIV status, and within groups, investigate associations of immune markers with bone density across Tanner stage. Using data and samples from 353 participants in a cross-sectional study in youth with perinatally acquired HIV (PHIV) and matched HIV-negative controls, distributions of inflammation and activation immune markers were described by sex and HIV status. Correlations and structural equation models (SEM) were used to explore marginal and multivariable associations of the immune markers with bone density and to assess whether patterns of association varied by sex and HIV status. Immune marker distributions did not differ by sex, but there were some differences by HIV status. Correlation patterns among bone, body composition, and immune markers were similar across the sex and HIV status groups. Conclusions from SEMs were limited by small sample sizes, but there was some indication that patterns of association between bone density and certain immune markers differed in male PHIV with more advanced Tanner stage compared to the other three groups. In conclusion, distributions of bone density, body composition, and immune markers may vary by sex and HIV status, although associations among these outcomes within sex and HIV status groups appear similar. Bone density of male PHIV appears to be more negatively affected than females, regardless of female HIV status. Larger longitudinal studies across Tanner stages are needed to further explore potential biological relationships between immune markers and bone density in youth living with HIV.

Factors influencing peak bone mass gain

Bone mass is a key determinant of osteoporosis and fragility fractures. Epidemiologic studies have shown that a 10% increase in peak bone mass (PBM) at the population level reduces the risk of fracture later in life by 50%. Low PBM is possibly due to the bone loss caused by various conditions or processes that occur during adolescence and young adulthood. Race, gender, and family history (genetics) are responsible for the majority of PBM, but other factors, such as physical activity, calcium and vitamin D intake, weight, smoking and alcohol consumption, socioeconomic status, age at menarche, and other secondary causes (diseases and medications), play important roles in PBM gain during childhood and adolescence. Hence, the optimization of lifestyle factors that affect PBM and bone strength is an important strategy to maximize PBM among adolescents and young people, and thus to reduce the low bone mass or osteoporosis risk in later life. This review aims to summarize the available evidence for the common but important factors that influence bone mass gain during growth and development and discuss the advances of developing high PBM.

Practical Guidance for Prevention and Management of Glucocorticoid-Induced Osteoporosis for the Allergist/Immunologist

Osteoporosis is a silent disorder with dire consequences, and glucocorticoid use remains the most common iatrogenic cause illustrated by the fact that 30% to 50% of subjects on such long-term therapy experience fractures (Oimomi M, Nakamichi T, Ohara T, Sakai M, Igaki N, Hata F, et al. Fructose-related glycation. Diabetes Res Clin Pract 1989;7:137-9; Reid IR. Glucocorticoid osteoporosis--mechanisms and management. Eur J Endocrinol 1997;137:209-17). By directly affecting bone quality while actively used, glucocorticoids increase the risk of fracture that is independent of a subject's bone density status at the time (Weinstein RS. True strength. J Bone Miner Res 2000;15:621-5). A large number of subjects seen in an allergy and immunology clinic have asthma, chronic rhinosinusitis, or other chronic inflammatory diseases, necessitating the use of these medications and placing them at higher risk for this disease. Data on the effects of both oral and inhaled glucocorticoids on fracture risk are presented. This review concretizes the importance of osteoporosis, its pathophysiology, and provides practical guidelines to prevent and treat it. Management recommendations are tailored to 2 different age groups. The first group consists of children, adolescents, and adults 40 years or younger with a focus on attaining peak bone mass. The second group consists of adults 40 years or older where the use of imaging modalities and Fracture Risk Assessment Tool scores helps triage subjects into fracture risk categories. Those at moderate to high risk require bone-sparing medications. Universal preventive measures for both groups are reviewed. Complicated and severe cases may need additional expertise by an endocrinologist or rheumatologist.

Why is primary hyperparathyroidism more severe in children?

The disease presentation of primary hyperparathyroidism (PHPT) is more severe in children. We hypothesize that this difference in disease presentation is a result of several factors including a delay in diagnosis, age-related differences in calcium metabolism and bone turnover, and the influence of the growth hormone (GH)/insulin growth factor-1 (IGF-1) axis. Only the first two explanations for the heightened disease severity of PHPT in children have been previously discussed in the literature. In regards to the potential role GH and IGF-1 may play in this disparity, previous studies have documented decreases in GH and IGF-1 secretion in symptomatic adult PHPT patients potentially influencing the severity of the patients' disease presentation. While these studies have yet to be replicated in the pediatric population, given that both GH and IGF-1 are important for the achievement of peak bone mass in young individuals, it is logical to infer that the GH/IGF-1 axis may be partly responsible for the severe presentation of PHPT in children.

DXA in Children and Adolescents

DXA plays a critical role in assessing skeletal health and disease, as well as, fat and muscle status in children and adolescents. Quality DXA requires training, expertise and attention to details, as in adults, but there are key differences in performing and interpretations in children. These include choice of measurement site, skills required, reference data and software, and considerations for indications and underlying disorders to facilitate correct interpretation. The International Society for Clinical Densitometry (ISCD) has been pivotal in establishing official positions and training for people who are interested in performing or interpreting such examinations, and guiding clinicians who may request such studies. However training in the performance and interpretation of scans of individuals with more complex needs falls outside the scope of this review, and consideration should be given to refer such examinations to a specialist pediatric DXA unit. Others may be scanned and reported by those with expertise in densitometry, as long as due diligence is paid to standard quality procedures, as well as knowledge of the special circumstances and training required for this field. In this invited review we outline some of these considerations, highlight key messages, and provide some appropriate references to help guide clinicians, technologists and scientists involved or interested in DXA use in children and adolescents.

Dual-energy X-ray absorptiometry bone densitometry in pediatrics: a practical review and update

The assessment of pediatric bone mineral content and density is an evolving field. In this manuscript we provide a practical review and update on the interpretation of dual-energy X-ray absorptiometry (DXA) in pediatrics including historical perspectives as well as a discussion of the recently published 2019 Official Position Statements of the International Society of Clinical Densitometry (ISCD) that apply to children.

Screening for Bone Mineral Density and Assessment Knowledge Level of Low Peak Bone Risk Factors and Preventive Practices Among Kuwaiti Future Mothers

Background

Attaining greater peak bone mass (PBM) prior to the onset of bone loss is getting increasing public health attention as healthy strong bones are essential to maintain our life. Females are more susceptible to bone loss. Knowledge and awareness about low peak bone mass and its related risk factors are important contributors to its preventive behavior.

Objective

To screen apparently healthy young Kuwaiti future mothers for low bone mineral density (BMD) and to assess their knowledge level about determinants of PBM and preventive practices.

Methods

A cross-sectional comparative study on 445 eligible women aged 18–35 years (either students or employees from Kuwait University) was performed. Data on socio-demographic and lifestyle variables were obtained by a semi-structured questionnaire. Their knowledge was assessed using the modified Osteoporosis Knowledge Assessment Tool (OKAT). Bone mineral Density (BMD) was measured using Quantitative Ultrasonography (QUS).

Results

More than half (59.3%) of females had poor knowledge. A statistically significant relation was noted between the overall knowledge score and age, college, occupation, and socioeconomic class (P<0.05 for each). Only 13.9% have low Z-score by QUS. By logistic regression, less carbonated beverages and coffee consumption positively affect BMD, while inadequate exercises level, indoor exposure to sunlight, and less frequency of brisk walking negatively affect BMD.

Conclusion

Unacceptable knowledge score significantly associated with BMD Z-score status. More attention should be devoted to education programs targeting adolescents and young females to promote knowledge about PBM and practice towards accrual and maintenance of bone health.

Bone Geometry, Density, and Microarchitecture in the Distal Radius and Tibia in Adults With Marfan Syndrome Assessed by HR-pQCT

Marfan syndrome (MFS) is a hereditary disorder of connective tissue caused by mutations in the fibrillin-1 gene. Studies have shown that patients with MFS have lower bone mass, but little is known about the other constituents of bone strength. We hypothesize that patients with MFS will have larger bone area and compromised cortical microarchitecture compared with non-MFS individuals. A total of 74 adult patients with MFS and 145 age- and sex-matched non-MFS reference individuals were included in this study. High-resolution peripheral quantitative computed tomography (HR-pQCT) at the distal radius and distal tibia and dual-energy X-ray absorptiometry of total hip and the lumbar spine were performed, and bone turnover and sex hormones were measured. Patients with MFS had significantly lower areal bone mineral density (BMD) at the total spine (-13%) and total hip (-7%) when compared with the reference group. Patients with MFS had significantly larger total bone area at both the radius (+27%) and tibia (+34%). Volumetric BMD at both measured sites showed significantly reduced total, trabecular, and cortical volumetric BMD in patients with MFS compared with the reference group. The microarchitectural parameters at the radius and tibia were compromised in patients with MFS with significantly reduced trabecular number and thickness, leading to a higher trabecular separation and significantly reduced cortical thickness and increased cortical porosity compared with the reference group. The differences in bone density, geometry, or microarchitecture were not explained by increased bone turnover markers or circulating levels of sex hormones. We conclude patients with MFS have altered bone geometry, altered bone microstructure, and lower bone mass (lower areal BMD and volumetric BMD at all sites) compared with healthy reference individuals. Future studies should focus on fracture rates and fracture risk in adult and aging patients with MFS. © 2020 American Society for Bone and Mineral Research (ASBMR).

The effects of adolescent laparoscopic adjustable gastric band and sleeve gastrectomy on markers of bone health and bone turnover

25-hydroxy vitamin D (25 OHD) deficiency and secondary hyperparathyroidism have been seen after metabolic and bariatric surgery, but data are lacking on the bone health outcomes of adolescent sleeve gastrectomy (SG). The purpose of this study was to examine bone-related nutrition after SG, compared to laparoscopic adjustable gastric band (LAGB), and trend bone turnover markers following SG. This is an observational study of 197 adolescents who underwent LAGB (n = 98) or SG (n = 99). Bone health labs were collected at baseline and 6 and/or 12 months after LAGB or SG, with additional analysis of bone turnover markers in the SG group. Calcium and 25 OHD levels increased at 6 and 12 months after LAGB and SG, with no difference between the surgeries. Parathyroid hormone levels decreased only in the SG group. SG patients had increased osteocalcin and carboxy-terminal cross-linking telopeptide of type 1 collagen (CTX) at 6 and 12 months post-SG, although CTX decreased between 6 and 12 months. Excess weight loss at 6 months predicted the rise in CTX, but the changes in osteocalcin and CTX could not be attributed to 25 OHD deficiency, hypocalcemia or hyperparathyroidism. Patients had improved 25 OHD levels post-surgery, which may be secondary to stringent vitamin supplementation guidelines. However, there were marked increases in bone turnover markers following SG. More studies are needed to evaluate the effects of SG on adolescent bone health and to correlate the early changes in bone turnover with bone mineral density and fracture risk.

Peripheral quantitative computed tomography (pQCT) in 12- and 24-month-old children - Practical aspects and descriptive data

BACKGROUND

Peripheral quantitative computed tomography (pQCT) is a useful tool to assess detailed bone characteristics. Its utility in infants is however limited due to lack of reference data and technical challenges. The purpose of this study was to provide data on length- and weight-adjusted pQCT values and to present a quality grading system for healthy children aged 12 and 24 months.

MATERIAL AND METHODS

As a part of the Vitamin D intervention in Infants (VIDI) trial, we collected pQCT and anthropometric data from 855 children at 12 months and from 784 children at 24 months. Bone mineral content (BMC; mg/mm), volumetric bone mineral density (vBMD; mg/cm³), cross-sectional area (CSA; mm²), polar-moment of inertia (PMI; mm⁴), and periosteal circumference (PsC; mm) were assessed for total bone at 20% distal site of the left tibia using pQCT (Stratec XCT2000L). We evaluated the impact of scan quality on bone measures. Total bone parameters were assessed for boys and girls separately. The means of the bone parameters were also compared in relation to age. The associations between bone parameters and weight, length, sex and scan quality were analyzed.

RESULTS

We included scans with sufficient quality (Grade 1-5) in the final analyses: 679/855 (79%) at 12 months and 709/784 (90%) at 24 months. Altogether 39% of the scans at 12 months and 51% at 24 months were of good or excellent quality (Grade 1-2). Scan quality had an impact on BMCs at 12 and 24 months (p = 0.001 and p = 0.017, respectively) but not on other bone parameters. Boys presented greater total bone BMC, CSA, PMI and PsC values at 12 and 24 months but vBMDs were similar. All bone parameters showed a significant increase between 12 and 24 months for both sexes. When adjusting bone parameters for weight, length and scan quality, differences between sexes disappeared. Weight was the strongest modifier of BMC, CSA, PMI and PsS at 12 and 24 months.

CONCLUSIONS

This study increases our understanding on bone parameters in young children and demonstrates the suitability of pQCT in bone research in infants. The described pQCT data and scan quality grading system should prove useful in evaluating data reliability in research settings.

CLINICAL TRIAL REGISTRATION NUMBER

NCT1723852.

The influence of biological maturation and neuromuscular performance on peak bone mineral density in children

BACKGROUND

The growth and development cycle of the adult is characterized by substantial changes in physical size and maturity, and is controlled by the simultaneous influence of genetic components and the environment. Changes in the development of bones, muscles and adipose tissue are among the most important aspects of adolescent physical development. The aim of this research was to examine the correlation between bone mineral density (BMD) and neuromuscular performance in children at different stages of maturation.

METHODS

The study included 31 participants of both sexes (11.7±1.89 years). Body composition was assessed through bone densitometry using an energy duo X-ray source. The neuromuscular performance of the upper limbs was analyzed by the medicine ball hand grip and throwing tests. The lower limbs by the vertical counter-motion jump test, and skeletal maturation was analyzed by bone age. Maturation was used as an effect control between the association of BMD and neuromuscular performance.

RESULTS

The results demonstrated significant associations between the performance of upper (P<0.0001) and lower (P=0.01) limbs and BMD. On inter-group comparison for only the accelerated maturational stage, male participants had greater BMD than female participants (P=0.001; effect size 3.13). Regarding the maturational stages, male participants in the accelerated maturational stage demonstrated higher BMD than those in the normal and delayed maturational stages (P=0.04; effect size 3.10), whereas female participants did not demonstrate significant differences in BMD accumulation.

CONCLUSIONS

BMD has a strong correlation with the neuromuscular performance of upper and lower limbs of children of both sexes.

Effects of Sleeve Gastrectomy on Bone Marrow Adipose Tissue in Adolescents and Young Adults with Obesity

CONTEXT

Sleeve gastrectomy (SG), the most common metabolic and bariatric surgery in adolescents, is associated with bone loss. Marrow adipose tissue (MAT) is a dynamic endocrine organ that responds to changes in nutrition and might serve as a novel biomarker for bone health. Two types of MAT have been described, which differ in anatomic location-proximal regulated MAT vs distal constitutive MAT.

OBJECTIVE

To determine the effects of SG on volumetric bone mineral density (vBMD) and MAT in adolescents with obesity. We hypothesized that SG would lead to a decrease in vBMD and differential changes in MAT.

DESIGN

12-month prospective study in 52 adolescents with moderate-to-severe obesity (38 female; mean age:17.5 ± 2.2 years; mean BMI 45.2 ± 7.0 kg/m2), comprising 26 subjects before and after SG and 26 nonsurgical controls.

MAIN OUTCOME MEASURES

Lumbar vBMD by quantitative computed tomography; MAT of the lumbar spine, femur and tibia by proton magnetic resonance spectroscopy; abdominal fat and thigh muscle by magnetic resonance imaging.

RESULTS

Adolescents lost 34.1 ± 13.1 kg after SG vs 0.3 ± 8.4 kg in the control group (P < 0.001). Lumbar vBMD decreased in the SG group (P = 0.04) and this change was associated with a reduction in weight and muscle area (P < 0.05) and an increase in lumbar MAT (P = 0.0002). MAT of the femur and tibia decreased after SG vs controls (P < 0.05); however, the differences were no longer significant after controlling for change in weight.

CONCLUSION

SG in adolescents decreased lumbar vBMD associated with an increase in lumbar MAT and decrease in extremity MAT. This demonstrates differential changes of regulated MAT in the lumbar spine and constitutive MAT in the distal skeleton in adolescents in response to SG.

Moving more: physical activity and its positive effects on long term conditions in children and young people

While the benefits of regular participation in physical activity in children and young people are clear, misconceptions have developed about the possible negative effects and potential complications of exercise on long-term conditions such as epilepsy, asthma and diabetes. Over the last decade evidence has emerged supporting the positive impact that physical activity has on long-term conditions. Previous concerns were raised about the risks of hypoglycaemia in children with type 1 diabetes mellitus (T1DM) thus limiting participation in sports. Importantly, physical activity improves the metabolic profile, bone mineral density, cardiorespiratory fitness and insulin sensitivity while lowering mortality risk in children with T1DM. Children with asthma were prevented from doing exercise due to concerns about precipitating an acute asthmatic episode. To the contrary, physical activity interventions have consistently shown an increase in cardiovascular fitness, physical capacity, asthma-free days and quality of life in childhood asthmatics. Children with epilepsy are often excluded from sports due to concerns relating to increased seizure frequency, yet evidence suggests that this is not the case. The evidence supporting physical activity in childhood survivors of cancer is growing but still primarily confined to patients with acute lymphoblastic leukaemia. Participation in sports and physical activity also reduces mental health problems developing in adolescence. While further research is required to investigate benefits of physical activity on specific aspects of long-term conditions in children, in general this group should be advised to increase participation in sports and exercise as a means of improving long-term physical and mental health.

Intensive weight gain therapy in patients with anorexia nervosa results in improved serum tartrate-resistant acid phosphatase (TRAP) 5a and 5b isoform protein levels

AIM

Tartrate-resistant acid phosphatase (TRAP) exists as isoforms 5a and 5b. TRAP 5a is a biomarker of chronic inflammation and influences adipose tissue and 5b associates with bone metabolism/pathologies. The aim was to investigate the association of serum TRAP 5a/5b isoforms with fat and bone markers and anthropometric parameters in patients with anorexia nervosa (AN) during weight gain therapy.

METHODS

Twenty-five Swedish female AN patients, age 16-24 years, were treated for 12 weeks with a high-energy diet with six meals daily. Serum TRAP 5a/5b, markers of fat/glucose metabolism, markers of bone resorption and formation were measured. Parameters of bone and body composition were assessed by dual-energy X-ray absorptiometry and peripheral quantitative computed tomography.

RESULTS

BMI increased from median 15.4 kg/m² to 19.0 kg/m², p < 0.0001. TRAP 5a and 5a/5b ratio increased but TRAP 5b decreased during the study. TRAP Δ5a and Δ5b correlated with Δinsulin and Δadiponectin, respectively. TRAP 5b correlated with trabecular density at start but not at week 12. At 12 weeks, TRAP 5b correlated with CTX, and Δ decrease in TRAP 5b correlated to Δ increase in bone-specific alkaline phosphatase.

CONCLUSIONS

This clinical interventional study resulted in increased BMI in patients with AN. The decreased TRAP 5b protein levels confirm a role for TRAP 5b as a marker of bone resorption, whereas increased TRAP 5a seemed to derive from systemic changes in bone as well as metabolic changes. The combined detection of TRAP 5a and TRAP 5b in serum could be an indicator of improved bone metabolism.

LEVEL OF EVIDENCE

Level III, prospective interventional cohort study.

Use of Model-Informed Drug Development to Streamline Development of Long-Acting Products: Can These Successes Be Translated to Long-Acting Hormonal Contraceptives?

Long-acting contraceptives are the most effective reversible contraceptive methods. Increasing patients' access to these contraceptives may translate into fewer unintended pregnancies and lead to substantial individual and public health benefits. However, development of long-acting products can be complex and challenging. This review provides (a) an overview of representative development programs for long-acting antipsychotics as cases for conceptual translation to long-acting contraceptives, (b) several case examples on how modeling and simulation have been used to streamline the development of long-acting products, and (c) examples of challenges andopportunities in developing long-acting contraceptives and information on how exposure-response relationships of commonly used progestins may enable regulators and developers to rely on prior findings of effectiveness and safety from an approved contraceptive to streamline the development of long-acting contraceptives. The US Food and Drug Administration is seeking assistance from stakeholders to provide data from studies in which pharmacokinetic and pharmacodynamic or clinical outcomes of hormonal contraceptives were evaluated and not previously submitted.

Low bone mineral density in children and adolescents with cancer

Maximizing accumulation of bone mass during childhood and adolescence is essential to attaining optimal peak bone mass. Childhood cancer survivors (CCS) have lower bone mineral density (BMD) than the general population. Chemotherapeutic agents including steroids and radiotherapy can affect BMD. Cancer itself, hormonal insufficiency, a poor nutritional state, and a deficit of physical activities during or after treatment also influence BMD in CCS, resulting in failure to achieve appropriate peak bone mass. Low BMD in childhood and adolescence can lead to osteoporosis in adult life and complications such as bone pain, bone deformity, and fractures. Thus, BMD in CCS should be monitored with appropriate intervention. Adequate intake of calcium and vitamin D and an increase in physical activity are recommended. Timely supplements of hormones are needed in some cases. Some publications have reported that bisphosphonate therapies using pamidronate or alendronate were well tolerated in CCS and helped increase BMD.

The Effect of the Supplementation of a Diet Low in Calcium and Phosphorus with Either Sheep Milk or Cow Milk on the Physical and Mechanical Characteristics of Bone using A Rat Model

This study assessed the effect of cow milk (CM) and sheep milk (SM) consumption on the micro-structure, mechanical function, and mineral composition of rat femora in a male weanling rat model. Male weanling rats were fed a basal diet with a 50% reduction in calcium and phosphorus content (low Ca/P-diet) supplemented with either SM or CM. Rats were fed for 28 days, after which the femora were harvested and stored. The femora were analyzed by μ-CT, three-point bending, and inductively coupled plasma-mass spectrometry (ICP-MS). The addition of either milk to the low Ca/P-diet significantly increased (p < 0.05) trabecular bone volume, trabecular bone surface density, trabecular number, cortical bone volume, and maximum force, when compared to rats that consumed only the low Ca/P-diet. The consumption of either milk resulted in a significant decrease (p < 0.05) in trabecular pattern factor, and cortical bone surface to volume ratio when compared to rats that consumed only the low Ca/P-diet. The results were achieved with a lower consumption of SM compared to that of CM (p < 0.05). This work indicates that SM and CM can help overcome the effects on bone of a restriction in calcium and phosphorus intake.

Osteoporosis in Premenopausal Women: A Clinical Narrative Review by the ECTS and the IOF

CONTEXT

Consensus regarding diagnosis and management of osteoporosis in premenopausal women (PW) is still lacking due to few studies carried out in this population.

DESIGN

The European Calcified Tissue Society and the International Osteoporosis Foundation convened a working group to produce an updated review of literature published after 2017 on this topic.

RESULTS

Fragility fractures in PW are rare and mostly due to secondary osteoporosis (ie, in presence of an underlying disease such as hormonal, inflammatory, or digestive disorders). In absence of another disorder, low bone mineral density (BMD) together with fragility fractures qualifies as idiopathic osteoporosis. In contrast, low BMD alone does not necessarily represent osteoporosis in absence of bone microarchitectural abnormalities. BMD increases in PW with osteoporosis when the underlying disease is treated. For example, in celiac disease, an increase of 9% in radius trabecular volumetric density was achieved after 1 year of gluten-free diet, while anti-tumor necrosis factor alpha improved BMD in PW with inflammatory bowel diseases. In amenorrhea, including anorexia nervosa, appropriately delivered estrogen replacement therapy can also improve BMD. Alternatively, antiresorptive or anabolic therapy has been shown to improve BMD in a variety of conditions, the range of improvement (3%-16%) depending on skeletal site and the nature of the secondary cause. No studies were powered to demonstrate fracture reduction. The effects of bisphosphonates in childbearing women have been scantly studied and caution is needed.

CONCLUSION

The majority of PW with osteoporosis have an underlying disease. Specific therapy of these diseases, as well as antiresorptive and anabolic drugs, improve BMD, but without evidence of fracture reduction.

Impact of sleeve gastrectomy on hip structural analysis in adolescents and young adults with obesity

BACKGROUND

Sleeve gastrectomy (SG), the most commonly performed metabolic and bariatric surgery, is associated with reductions in areal bone mineral density at multiple sites, and changes in bone structure at the distal radius and tibia without reductions in strength estimates at these peripheral sites. Data are lacking regarding effects on hip strength estimates.

OBJECTIVE

To evaluate effects of SG on measures of hip structural analysis in adolescents and young adults over 12 months using dual-energy x-ray absorptiometry.

SETTINGS

Translational and Clinical Research Center.

METHODS

We enrolled 48 youth 14- to 22-years old with moderate-to-severe obesity; 24 underwent SG and 24 controls were followed without surgery (18 females, 6 males in each group). Hip structure was assessed using dual-energy x-ray absorptiometry at baseline and 12 months. Analyses are adjusted for age, sex, race, and the baseline bone measure.

RESULTS

The SG group lost 25.9% weight versus .3% in controls. Compared with controls, SG had reductions in narrow neck, intertrochanteric and femoral shaft bone mineral density Z-scores (P ≤ .012). Furthermore, SG had greater reductions in narrow neck and intertrochanteric region (but not femoral shaft) cross-sectional area, cortical thickness, cross-sectional moment of inertia and section modulus, and increases in buckling ratio (P ≤ .039). Differences were attenuated after adjusting for 12-month body mass index change. At 12 months, differences were minimal after adjusting for age, sex, race, and weight.

CONCLUSIONS

Over 12 months, SG had negative effects at the narrow neck and intertrochanteric regions of the hip, but not the femoral shaft. Reduced body mass index may compensate for these deleterious effects on bone.

Bone Mineral Reference Values for Athletes 11 to 20 Years of Age

Objectives. Training for sport is associated with the development of bone minerals, and the need for reference data based on athletes is often indicated. The purpose of this study was to develop a reference for bone mineral density (BMD) and content (BMC) specific for youth athletes of both sexes participating in several sports. Methods DEXA (dual energy X-ray absorptiometry) was used for total body measurements of bone minerals in 1385 athletes 11 to 20 years, 1019 males and 366 females. The athletes were training in several sports at Hungarian academies. Reference values for total bone mineral density and bone mineral content, and also BMD excluding the head (total body less head, TBLH) were developed using the LMS chartmaker pro version 2.3. Results. The centile distributions for BMD and BMC of the athletes differed significantly from those of the age- and sex-specific references for the general population. The youth athletes had higher BMD and BMC than those of the reference for the general population. Conclusion. The potential utility of the DEXA reference for male and female youth athletes may assist in monitoring changes in the BMC and BMD associated with normal growth and maturation, and perhaps more importantly, may be useful in monitoring changes specific to different phases of sport-specific training protocols.

Protein quality and safety evaluation of sarcoplasmic protein derived from silver carp (Hypophthalmichthys molitrix) using a rat model

Consisting of 25 to 30% of protein in carp, water-soluble sarcoplasmic proteins lost in wash water, have been recovered and freeze-dried into a protein-rich powder. Study objectives were to evaluate protein quality and safety of a silver carp sarcoplasm derived protein powder (CSP) compared to commercial protein supplements, casein, and whey. In vivo protein quality assessment of CSP showed a lower (P < 0.05) protein digestibility corrected amino acid score compared to the commercial protein sources. Despite greater (P < 0.05) fecal amino acid excretion in casein-fed rats, there were no significant differences in liver and muscle amino acid profiles. All low (10% kcal) protein diets supported growth with the normal range. However, whey protein supplementation resulted in greater (P < 0.05) adiposity. CSP, casein, or whey-fed rats showed no differences in major organ weights, renal damage biomarkers, or bone indices. Collectively, results indicated CSP was safe with protein quality comparable to casein. PRACTICAL APPLICATION: As much as 40 percent of protein in fish can be lost due to sarcoplasmic protein solubilization in processing wash water. Silver carp sarcoplasm protein powder may have similar commercial potential as a sustainable and nutritious alternative to whey and casein proteins. This project aimed to verify the protein quality and safety of this economical protein source.

Oral contraceptive use, bone mineral density, and bone turnover markers over 12 months in college-aged females

INTRODUCTION

The purpose of this study was to compare bone mineral density (BMD) and bone turnover markers between combined oral contraceptive (COC) and non-COC users over 12 months.

MATERIALS AND METHODS

COC users (n = 34, age = 19.2 ± 0.5) and non-COC users (n = 28, age = 19.3 ± 0.6) provided serum at baseline, 6 months, and 12 months. C-terminal telopepetides (CTX) and pro-collagen type 1 N-terminal propeptides (P1NP) were determined using ELISA. BMD was measured at the three time points using dual-energy x-ray absorptiometry (DXA).

RESULTS

COC users had greater CTX than non-COC users at baseline (18.6 ± 8.2 vs. 13.8 ± 5.3 ng/mL, P = 0.021) and 6 months (20.4 ± 10.3 vs. 14.2 ± 8.5 ng/mL, P = 0.018). Controlling for lean mass, groups were similar in BMD. Over 12 months, non-COC users maintained BMD at the spine, while the COC users declined 2.2% in lateral spine BMD (0.773 ± 0.014 to 0.756 ± 0.014 g/cm², P = 0.03) and 0.7% in anterior-posterior spine BMD (1.005 ± 0.015 to 0.998 ± 0.015 g/cm², P = 0.069). Non-COC users increased in BMD of the whole body over 12 months (P < 0.001) while COC users had no change. Women who began COCs within 4 years after menarche had lower BMD at the hip and whole body. Women taking very low dose COCs (20 mcg ethinyl estradiol, EE) significantly declined in CTX, P1NP, and lateral spine BMD in comparison to participants using low dose COCs (30/35 mcg EE).

CONCLUSION

College-aged women who did not use COCs increased BMD of the whole body, while COC users had elevated bone turnover, declines in spinal BMD, and lack of bone acquisition of the whole body over 12 months. Young females who initiate COC use early after menarche may experience skeletal detriments.

Adolescents and Bone Health

Adolescence is a critical time for the acquisition of peak bone mass. There are modifiable factors that may influence bone health in an adolescent. For those at risk for bone fragility, initial management includes optimization of calcium and vitamin D, weight-bearing exercise, and maintenance of a normal body weight. In certain scenarios, bisphosphonate treatment is indicated, as is reviewed. How hormonal contraceptives affect bone mineral density is unclear, but in patients with risk factors or known bone fragility, prescribers should consider their skeletal effects. Some conditions, including restrictive eating disorders and primary ovarian insufficiency, warrant long-term monitoring of bone health.

Bone Update: Is It Still an Issue Without Tenofovir Disoproxil Fumarate?

PURPOSE OF REVIEW

In the era of modern bone-friendly antiretroviral therapy (ART) regimens for people living with HIV (PLWH), this review discusses the research gaps and management concerns that remain for individuals who have already been exposed to ART with negative effects on bone metabolism, especially children and adolescents who have not acquired peak bone mass, and older adults who have additional risk factors for fracture.

RECENT FINDINGS

Data now support the use of avoidance of TDF and use of bone-friendly regimens that include integrase strand transfer inhibitors in PLWH with increased risk of fracture for either ART initiation or switch. Despite significant advances in our understanding of ART choice for PLWH with regard to bone health, additional diagnostic tests to determine fracture risk and management strategies beyond ART choice are necessary, especially in vulnerable PLWH populations, such as children and adolescents and older adults.

Vitamin D and bone health in adults: a systematic review and meta-analysis

Low bone health is associated with vitamin D deficiency in older individuals; however, this association is not well established in adults. The aim of the study was to analyze the association between serum concentrations of 25-hydroxyvitamin D and bone health in adults by systematic review and meta-analysis. The search was carried out in the LILACS, PubMed, Scopus, Web of Science, ScienceDirect databases from March 2017 to October 2018 with adult individuals (20-59 years). Bone health was evaluation performed through dual X-ray absorptiometry and serum concentrations of 25(OH)D. The random effect model was used to analyze data from bone mineral content and bone mineral. Random effects models were used and the sources of heterogeneity were explored by means of meta-regression. Thirty-five articles were selected. There was positive correlation between vitamin D and bone health in most of the evaluated sites. Correlation was observed in the analysis of subgroups for lumbar spine among men. When stratified, the studies presented high heterogeneity, which was explained by the sample size, mean serum vitamin D levels and risk of bias. Vitamin D is positively correlated to bone health in adult individuals.

Bone outcomes following sleeve gastrectomy in adolescents and young adults with obesity versus non-surgical controls

BACKGROUND

Sleeve gastrectomy is the most commonly performed weight loss surgery in adolescents with moderate-to-severe obesity. While studies in adults have reported on the deleterious effects of gastric bypass surgery on bone structure and strength estimates, data are lacking for the impact of sleeve gastrectomy on these measures in adolescents.

OBJECTIVE

To evaluate the impact of sleeve gastrectomy on bone outcomes in adolescents and young adults over 12 months using dual energy X-ray absorptiometry (DXA) and high resolution peripheral quantitative computed tomography (HRpQCT).

PARTICIPANTS AND METHODS

We enrolled 44 youth 14-22 years old with moderate to severe obesity; 22 underwent sleeve gastrectomy and 22 were followed without surgery (16 females and 6 males in each group). At baseline and 12 months, DXA was used to assess areal bone mineral density (aBMD), HRpQCT of the distal radius and tibia was performed to assess bone geometry, microarchitecture and volumetric BMD (vBMD), and finite element analysis to assess strength estimates (stiffness and failure load). These analyses were adjusted for age, sex, race and the bone measure at baseline. Fasting blood samples were assessed for calcium, phosphorus, and 25(OH) vitamin D (25OHD) levels.

RESULTS

Over 12-months, the surgical group lost 27.2% of body weight compared to 0.1% in the non-surgical (control) group. Groups did not differ for changes in 25OHD levels (p = 0.186). Compared to controls, the surgical group had reductions in femoral neck and total hip aBMD Z-scores (p ≤ 0.0006). At the distal tibia, compared to controls, the surgical group had reductions in cortical area and thickness and trabecular number, and increases in trabecular area and separation (p ≤ 0.026). At the distal radius, the surgical group had greater reductions in trabecular vBMD, than controls (p = 0.010). The surgical group had an increase in cortical vBMD at both sites (p ≤ 0.040), possibly from a decrease in cortical porosity (p ≤ 0.024). Most, but not all, differences were attenuated after adjusting for 12-month change in BMI. Groups did not differ for changes in strength estimates over time, except that increases in tibial stiffness were lower in the surgical group (p = 0.044) after adjusting for 12-month change in BMI.

CONCLUSIONS

Over 12 months, weight loss associated with sleeve gastrectomy in adolescents had negative effects on areal BMD and certain HRpQCT parameters. However, bone strength estimates remained stable, possibly because of a simultaneous decrease in cortical porosity and increase in cortical volumetric BMD. Additional research is necessary to determine the relative contribution(s) of weight loss and the metabolic effects of surgery on bone outcomes, and whether the observed effects on bone stabilize or progress over time.

Obesity and Insulin Resistance, Not Polycystic Ovary Syndrome, Are Independent Predictors of Bone Mineral Density in Adolescents and Young Women

INTRODUCTION

Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders that affects females of reproductive age. The characteristic features of PCOS individually have opposing effects on bone mineral density (BMD); however, their cumulative effect on BMD has not been clearly defined. Adolescence and young adulthood span a crucial period in achieving peak bone mass. Thus, a better understanding of the impact of PCOS on BMD in this age group is needed.

OBJECTIVES

To determine whether BMD is different between young females with PCOS and controls and to identify factors that influence BMD in this population.

METHODS

Data from four cross-sectional studies with a total of 170 females aged 12-25 years with PCOS (n = 123) and controls (n = 47) with a wide range of BMIs (18.7-53.4 kg/m2) were analyzed. Participants had fasting glucose, insulin, and free and total testosterone concentrations measured. HOMA-IR was calculated. Whole-body BMD was assessed by dual-energy X-ray absorptiometry. Multiple regression analysis for predicting BMD included PCOS status, menstrual age, obesity, HOMA-IR, and free testosterone.

RESULTS

HOMA-IR and total and free testosterone were significantly higher in PCOS compared to controls but there was no difference in BMD z-score between PCOS (0.8 ± 1.0) and controls (0.6 ± 1.0) (p = 0.36). Obesity (p = 0.03) and HOMA-IR (p = 0.02) were associated with BMD z-score.

CONCLUSIONS

Obesity status and insulin resistance, but not PCOS status, were each independently associated with BMD in adolescents and young women who spanned a wide range of BMIs.