Frequency of Delayed Puberty in Boys with Contemporary Management of Duchenne Muscular Dystrophy.

Background: Delayed puberty is thought to be common in boys with Duchenne muscular dystrophy (DMD) treated with long term oral glucocorticoid. This study aims to report the frequency of delayed puberty in DMD from examination by a paediatric endocrinologist alongside detailed endocrine investigations. Methods: All boys with DMD aged at least 14 years in January 2022 known to the paediatric neuromuscular service (2016-2022) were included in this study. Delayed puberty was defined based on testicular volume and genital staging in comparison to published puberty nomogram. Results: Twenty-four out of 37 boys (65%) had evidence of delayed puberty, 23/24 (96%) of those with delayed puberty were on glucocorticoid therapy all of whom were on daily glucocorticoid. On the other hand, 7/13 (54%) of those with normal timing of puberty were on glucocorticoid; 2/7 (29%) were on the intermittent regimen. Of those who were on daily glucocorticoid therapy at the time of assessment of puberty, 23/28 (82%) had evidence of delayed puberty. In boys with delayed puberty, endocrine investigations showed low luteinizing hormone (LH) with undetectable testosterone levels, a pre-pubertal response with lutenizing hormone releasing hormone test and sub-optimal testosterone levels with prolonged human chorionic gonadotropin stimulation. Conclusion: The frequency of delayed puberty in boys with DMD was 65%. Eighty-two percent of adolescent boys with DMD on daily glucocorticoid had evidence of delayed puberty. Biochemical investigations point to functional central hypogonadism in these adolescents. Our data supports the routine monitoring of puberty in boys with DMD.

Severity of acute phase reaction in children receiving the first dose of zoledronic acid and the impact of the underlying condition: a cross-sectional study.

INTRODUCTION: Zoledronic acid (ZA), used for treatment of children with osteoporosis, can cause acute phase reaction (APR) following the first infusion. Many institutions have a policy to admit and monitor all children for their first ZA infusion. OBJECTIVE: To determine if the APR with the first ZA dose warrants hospital-level care and evaluate if its severity correlates with the underlying condition. DESIGN: Retrospective cross-sectional analysis. SETTINGS: Two tertiary centres across the UK that run paediatric metabolic bone disease services. PATIENTS: Children who received first ZA infusion as inpatients at these centres. INTERVENTIONS: Nil. MAIN OUTCOME MEASURES: The Paediatric Early Warning Score (PEWS) and length of hospital stay to assess the severity of APR. RESULTS: 107 patients were included. Peak PEWS≤3 was found in 85% of children. 83% required admission for <24 hours. The various patient populations (osteogenesis imperfecta (OI), immobility-induced osteoporosis, idiopathic juvenile osteoporosis, systemic inflammatory disorders and steroid-induced osteoporosis, Duchenne muscular dystrophy (DMD)) did not differ significantly in the mean peak PEWS and the length of hospital stay. However, when compared directly, the group with DMD and that with systemic inflammatory disorders and steroid-induced osteoporosis differed significantly in the mean peak PEWS (p=0.011) and the length of hospital stay (p=0.048), respectively, as compared with the OI group. CONCLUSION: Most patients had a mild APR not requiring overnight hospital admission, after their first ZA dose. However, certain groups seem to suffer more severe APR and may warrant consideration of inpatient monitoring with the first infusion.

Anti-RANKL Therapy Prevents Glucocorticoid-Induced Bone Loss and Promotes Muscle Function in a Mouse Model of Duchenne Muscular Dystrophy.

Bisphosphonates prevent bone loss in glucocorticoid (GC)-treated boys with Duchenne muscular dystrophy (DMD) and are recommended as standard of care. Targeting receptor activator of nuclear factor kappa-B ligand (RANKL) may have advantages in DMD by ameliorating dystrophic skeletal muscle function in addition to their bone anti-resorptive properties. However, the potential effects of anti-RANKL treatment upon discontinuation in GC-induced animal models of DMD are unknown and need further investigation prior to exploration in the clinical research setting. In the first study, the effects of anti-RANKL and deflazacort (DFZ) on dystrophic skeletal muscle function and bone microstructure were assessed in mdx mice treated with DFZ or anti-RANKL, or both for 8 weeks. Anti-RANKL and DFZ improved grip force performance of mdx mice but an additive effect was not noted. However, anti-RANKL but not DFZ improved ex vivo contractile properties of dystrophic muscles. This functional improvement was associated with a reduction in muscle damage and fibrosis, and inflammatory cell number. Anti-RANKL treatment, with or without DFZ, also improved trabecular bone structure of mdx mice. In a second study, intravenous zoledronate (Zol) administration (1 or 2 doses) following 2 months of discontinuation of anti-RANKL treatment was mostly required to record an improvement in bone microarchitecture and biomechanical properties in DFZ-treated mdx mice. In conclusion, the ability of anti-RANKL therapy to restore muscle function has profound implications for DMD patients as it offers the possibility of improving skeletal muscle function without the steroid-related skeletal side effects.

Emergency and perioperative management of adrenal insufficiency in children and young people: British Society for Paediatric Endocrinology and Diabetes consensus guidance.

Adrenal insufficiency (AI) is characterised by lack of cortisol production from the adrenal glands. This can be a primary adrenal disorder or secondary to adrenocorticotropic hormone deficiency or suppression from exogenous glucocorticoids. Symptoms of AI in children may initially be non-specific and include growth faltering, lethargy, poor feeding, weight loss, abdominal pain, vomiting and lingering illnesses. AI is treated with replacement doses of hydrocortisone. At times of physiological stress such as illness, trauma or surgery, there is an increased requirement for exogenous glucocorticoids, which if untreated can lead to an adrenal crisis and death. There are no unified guidelines for those <18 years old in the UK, leading to substantial variation in the management of AI. This paper sets out guidance for intercurrent illness, medical, dental and surgical procedures to allow timely and appropriate recognition and treatment of AI and adrenal crisis for children and young people.

The Physiology and Mechanisms of Growth.

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The prevalence of hypertension in paediatric Turner syndrome: a systematic review and meta-analysis.

Cardiovascular related deaths account for over 40% of the excess mortality in Turner syndrome (TS). Hypertension, a modifiable risk factor for both aortic dilatation and dissection, is more commonly encountered in TS during childhood and adolescence. Treatment of hypertension is currently recommended beyond the age of 16 years in TS to help reduce the risk of aortic dissection. This study aims to determine the prevalence of hypertension in paediatric patients with TS and explore the associated methodologies of blood pressure evaluation reported in these studies. Three online databases were searched (Medline, Embase and Web of Science) for literature which reported a prevalence, or allowed calculation of prevalence, of hypertension in patients with TS who were 18 years of age or younger. Seventeen studies which met the primary eligibility criteria, with a total of 1948 patients, were included. The estimated pooled prevalence of hypertension in children and adolescents with TS was 16% (95% CI: 8.9-24.6%). There was significant heterogeneity detected between the studies. The prevalence of hypertension in those studies which assessed 24-h Ambulatory Blood Pressure Monitoring (ABPM) was 21.1% (95% CI: 15.2-27.6%) compared those which used another method of blood pressure measurement which was 13.5% (95% CI: 5.2-24.4%). Given the impact of hypertension with long-term health outcomes and the reversibility of these same outcomes by addressing abnormal blood pressure, prompt and early diagnosis of hypertension in young girls with TS should be prioritised. We recommend the use of 24-h ABPM in screening for hypertension in the paediatric TS population.

The effect of COVID-19 on the presentation of thyroid disease in children.

Introduction: Although studies suggest a potential link between COVID-19 and thyroid dysfunction in adults, there are insufficient data to confirm that association in children, and whether there is any effect on presentation to healthcare services. Aims: To identify whether presentations of thyroid dysfunction in children to a tertiary paediatric hospital changed as a result of the COVID-19 pandemic. Methods: A retrospective case note review was conducted of all children with abnormal thyroid function tests between 1st January 2016 and 31st December 2021 at a tertiary paediatric endocrine centre in the United Kingdom. Results: Overall, 244 children whose first presentation was within the timeframe of interest were included in this study, with a median age (range) of 11.5 (6.1, 16.8) years. Of these, 43 (18%) were hyperthyroid and 201 (82%) were hypothyroid. The greatest number of thyroid presentations occurred in 2021 (n=60, 25% of total over time period) and the fewest in 2020 (n=10, 4% of total over time period). Prior to this, the median (range) number of presentations per year was 34 (28, 39). There were no statistically significant differences in biochemistry, antibody status or other clinical characteristics between those who presented with hyperthyroidism prior to the pandemic or after. In those with hypothyroidism, baseline biochemistry was similar between the 2 groups, but the presence of other autoimmune conditions was greater pre-pandemic (17.2% vs 15.0%, p=0.03). In addition, patients were more likely to have transient thyroid dysfunction, which did not require treatment post-pandemic (70.0% vs 49.6%, p=0.0086). Conclusions: Although overall rates of presentation with thyroid dysfunction have not altered since the first wave of the COVID-19 pandemic, presentations with transient thyroid dysfunction, not requiring ongoing treatment have increased. Further research regarding the relationship between COVID-19 and thyroid function in children and young people, is needed.

Objective and subjective measures of sleep in men with Muscular Dystrophy.

PURPOSE: Despite poor sleep quality being recognised in Duchenne Muscular Dystrophy, reports from milder forms of Muscular Dystrophy (MD), and accompanied associations with quality of life (QoL), pain and fatigue, remain limited however. METHODS: Adult males (n = 15 Beckers MD (BMD), n = 12 Limb-Girdle MD (LGMD), n = 12 Fascioscapulohumeral (FSHD), n = 14 non-MD (CTRL)) completed assessments of body composition (Bio-electrical impedance), sleep (7-day 24-hour tri-axial accelerometer, Pittsburgh Sleep Quality Index (PSQI) and Insomnia Severity Index, QoL (SF36-v2), pain (Visual analogue scale), fatigue (Modified Fatigue Index Scale) and functional assessments (Brookes and Vignos). RESULTS: FSHD and BMD reported worse sleep than CTRL on the PSQI. FSHD scored worse than CTRL on the Insomnia Severity Index (P<0.05). 25-63% and 50-81% of adults with MD reported poor sleep quality using the Insomnia Severity Index and PSQI, respectively. Accelerometery identified no difference in sleep quality between groups. Associations were identified between sleep measures (PSQI global and insomnia severity) with mental or physical QoL in LGMD, BMD and FSHD. Multiple regression identified associations between sleep impairment and fatigue severity (all MDs), body composition (BMD & LGMD), upper and lower limb function (LGMD, FSHD) and age (FSHD). CONCLUSIONS: 25-81% of men with MD, depending on classification, experience sleep impairment, using self-report sleep measures. Whilst BMD and FSHD showed worse sleep outcomes than CTRL, no group difference was observed between LGMD and CTRL, however all groups showed associations with sleep impairment and higher levels of fatigue. These findings, and associations with measures of health and wellbeing, highlight an area for further research which could impact QoL in adults with MD.

3T-MRI-based age, sex and site-specific markers of musculoskeletal health in healthy children and young adults.

Objective: The aim of this study is to investigate the role of 3T-MRI in assessing musculoskeletal health in children and young people. Design: Bone, muscle and bone marrow imaging was performed in 161 healthy participants with a median age of 15.0 years (range, 8.0, 30.0). Methods: Detailed assessment of bone microarchitecture (constructive interference in the steady state (CISS) sequence, voxel size 0.2 × 0.2 × 0.4 mm3), bone geometry (T1-weighted turbo spin echo (TSE) sequence, voxel size 0.4 × 0.4 × 2 mm3) and bone marrow (1H-MRS, point resolved spectroscopy sequence (PRESS) (single voxel size 20 × 20 × 20 mm3) size and muscle adiposity (Dixon, voxel size 1.1 × 1.1 × 2 mm3). Results: There was an inverse association of apparent bone volume/total volume (appBV/TV) with age (r = -0.5, P < 0.0005). Cortical area, endosteal and periosteal circumferences and muscle cross-sectional area showed a positive association to age (r > 0.49, P < 0.0001). In those over 17 years of age, these parameters were also higher in males than females (P < 0.05). This sex difference was also evident for appBV/TV and bone marrow adiposity (BMA) in the older participants (P < 0.05). AppBV/TV showed a negative correlation with BMA (r = -0.22, P = 0.01) which also showed an association with muscle adiposity (r = 0.24, P = 0.04). Cortical geometric parameters were highly correlated with muscle area (r > 0.57, P < 0.01). Conclusions: In addition to providing deep insight into the normal relationships between bone, fat and muscle in young people, these novel data emphasize the role of MRI as a non-invasive method for performing a comprehensive and integrated assessment of musculoskeletal health in the growing skeleton.

Pathogenesis of Musculoskeletal Deficits in Children and Adults with Inflammatory Bowel Disease.

Musculoskeletal deficits are among the most commonly reported extra-intestinal manifestations and complications of inflammatory bowel disease (IBD), especially in those with Crohn's disease. The adverse effects of IBD on bone and muscle are multifactorial, including the direct effects of underlying inflammatory disease processes, nutritional deficits, and therapeutic effects. These factors also indirectly impact bone and muscle by interfering with regulatory pathways. Resultantly, individuals with IBD are at increased risk of osteoporosis and sarcopenia and associated musculoskeletal morbidity. In paediatric IBD, these factors may contribute to suboptimal bone and muscle accrual. This review evaluates the main pathogenic factors associated with musculoskeletal deficits in children and adults with IBD and summarises the current literature and understanding of the musculoskeletal phenotype in these patients.

Observer Agreement of Vertebral Fracture Grading Using Dual Energy Absorptiometry Vertebral Fracture Assessment in Duchenne Muscular Dystrophy.

Routine screening of the spine for vertebral fracture is recommended in the recent international standards of care for boys with Duchenne muscular dystrophy (DMD). Recent international consensus endorses the use of dual energy absorptiometry vertebral fracture assessment for identification of vertebral fractures in children, which could be used instead of spine radiographs. This study aims to evaluate the inter-observer agreement for vertebral fracture classification in boys with DMD, and the impact on clinical management. Dual energy absorptiometry vertebral fracture assessment and morphometric analysis in 39 boys was performed by a reader with no prior experience (R1) and 2 readers with experience (R2 and R3). Inter-observer concordance of vertebral fracture grading comparing R1 with R2 and R3 was substantial (Kappa 0.66, 95% CI 0.56, 0.76). Concordance between R2 and R3 was almost perfect (Kappa 0.93, 95% CI 0.89, 0.97) which did not lead to differences in clinical management. Grading by R1 in comparison to R2 and R3 would have led to change in management of 5/39 boys (13%), according to recent standards of care guidance. Structured education programme on identification of vertebral fractures should be explored to ensure consistency of reporting of this important health outcome measure in DMD.

Skeletal disproportion in girls with Turner syndrome and longitudinal change with growth-promoting therapy.

OBJECTIVE: Short stature in Turner syndrome (TS) may be accompanied by skeletal disproportion. This retrospective study investigates growth and disproportion from early childhood to adult height. STUDY DESIGN: Data were collected from 59 girls prior to growth hormone (rhGH) treatment and in 30 girls followed up longitudinally. Standard deviation scores (SDS) for height (Ht), sitting height (SH) and sub-ischial leg length (LL) were compared and a disproportion score (SH SDS - LL SDS) calculated. RESULTS: In 59 girls, mean (SD) age 6.6 (2.1) years prior to rhGH treatment, LL SDS of -3.4 (1.1) was significantly lower than SH SDS of -1.2 (0.8) [p < .001]. In girls with Ht SDS < -2.0, disproportion score was > +2.0 in 27 (63%), cf eight (50%) with Ht SDS ≥ -2.0. For the longitudinal analysis, skeletal disproportion prior to rhGH was +2.4 (1.1) and +1.7 (1.0) on rhGH but prior to introduction of oestrogen [p < .001]. Disproportion at adult height was +1.1 (0.8), which was less marked than at the earlier time points [p < .001 for both comparisons]. Change in disproportion SDS over the first two years of rhGH predicted overall change in disproportion from baseline to adult height [R2 51.7%, p < .001]. CONCLUSION: TS is associated with skeletal disproportion, which is more severe in the shortest girls and present in only half of those with milder degrees of short stature. Growth-promoting therapy may improve disproportion during both the childhood and pubertal phases of growth. Change in disproportion status two years after starting rhGH helps predict disproportion at adult height.

Clinical utility of urinary gonadotrophins in hypergonadotrophic states as Turner syndrome.

Background Girls with Turner syndrome (TS) are at an increased risk of primary ovarian insufficiency (POI). Good correlation between serum and urinary gonadotrophins exists in children assessed for disorders of puberty, but there is little evidence of their reliability in hypergonadotropic states. Objectives To determine whether there was a correlation between serum and urinary Luteinising Hormone (uLH) and Follicle-Stimulating Hormone (uFSH) in hypergonadotrophic states, and whether uFSH could suggest an ovarian failure in TS as Anti-Mullerian Hormone (AMH). Patients and Methods Retrospective cohort study of 37 TS girls attending the paediatric TS clinic in Glasgow between February 2015 and January 2019, in whom 96 non-timed spot urine samples were available with a median age at time of sample of 12.89 years (3.07-20.2 years). uLH and uFSH were measured by chemiluminescent microparticle immunoassay. Simultaneous serum gonadotrophins and AMH were available in 30 and 26 girls, respectively. AMH <4 pmol/L was considered indicative of ovarian failure. Results A strong correlation was found between serum LH and uLH (r 0.860, P<0.001) and serum FSH and uFSH (r 0.905, p<0.001). Among patients≥10 years not on oestrogen replacement, ROC curve identified uFSH as a reasonable marker for AMH<4 pmol/L uFSH of >10.85 U/L indicates an AMH <4 pmol/L with 75% sensitivity and 100 % specificity (AUC 0.875)with similar ability as serum FSH (AUC 0.906). Conclusion uLH and uFSH are non-invasive, useful and reliable markers of ovarian activity in hypergonadotropic states as TS. uFSH could provide an alternative to AMH (in centres which are limited by availability or cost) in revealing ovarian failure and requirement for oestrogen replacement in pubertal induction.

Muscle deficits with normal bone microarchitecture and geometry in young adults with well-controlled childhood-onset Crohn's disease.

BACKGROUND: Muscle-bone deficits are common in pediatric Crohn's disease; however, few studies have assessed long-term musculoskeletal outcomes in adults with childhood-onset Crohn's disease. This study assessed the prevalence of musculoskeletal deficits in young adults with childhood-onset Crohn's disease compared with healthy controls. METHODS: High-resolution MRI and MR spectroscopy were used to assess bone microarchitecture, cortical geometry and muscle area, and adiposity at distal femur and bone marrow adiposity (BMA) at lumbar spine. Muscle function and biomarkers of the muscle-bone unit were also assessed. RESULTS: Twenty-seven adults with Crohn's disease with median (range) age 23.2 years (18.0, 36.1) and 27 age and sex-matched controls were recruited. Trabecular microarchitecture, cortical geometry and BMA were not different between Crohn's disease and controls (P > 0.05 for all). Muscle area was lower (P = 0.01) and muscle fat fraction was higher (P = 0.04) at the distal femur in Crohn's disease compared to controls. Crohn's disease participants had lower grip strength [-4.3 kg (95% confidence interval (CI), -6.8 to -1.8), P = 0.001] and relative muscle power [-5.0 W/kg (95% CI, -8.8 to -1.2), P = 0.01]. Crohn's disease activity scores negatively associated with trabecular bone volume (r = -0.40, P = 0.04) and muscle area (r = -0.41, P = 0.03). CONCLUSION: Young adults with well-controlled Crohn's disease managed with contemporary therapies did not display abnormal bone microarchitecture or geometry at the distal femur but exhibited muscle deficits. The observed muscle deficits may predispose to musculoskeletal morbidity in future and interventions to improve muscle mass and function warrant investigation.

A comparison of the bone and growth phenotype of mdx, mdx:Cmah-/- and mdx:Utrn+/- murine models with the C57BL/10 wild-type mouse.

The muscular dystrophy X-linked (mdx) mouse is commonly used as a mouse model of Duchenne muscular dystrophy (DMD). Its phenotype is, however, mild, and other mouse models have been explored. The mdx:Cmah-/- mouse carries a human-like mutation in the Cmah gene and has a severe muscle phenotype, but its growth and bone development are unknown. In this study, we compared male mdx, mdx:Utrn+/-, mdx:Cmah-/- and wild-type (WT) mice at 3, 5 and 7 weeks of age to determine the suitability of the mdx:Cmah-/- mouse as a model for assessing growth and skeletal development in DMD. The mdx:Cmah-/- mice were lighter than WT mice at 3 weeks, but heavier at 7 weeks, and showed an increased growth rate at 5 weeks. Cortical bone fraction as assessed by micro-computed tomography was greater in both mdx and mdx:Cmah-/- mice versus WT mice at 7 weeks. Tissue mineral density was also higher in mdx:Cmah-/- mice at 3 and 7 weeks. Gene profiling of mdx:Cmah-/- bone identified increased expression of Igf1, Igf1r and Vegfa Both the mdx and mdx:Cmah-/- mice showed an increased proportion of regulated bone marrow adipose tissue (BMAT) but a reduction in constitutive BMAT. The mdx:Cmah-/- mice show evidence of catch-up growth and more rapid bone development. This pattern does not mimic the typical DMD growth trajectory and therefore the utility of the mdx:Cmah-/- mouse for studying growth and skeletal development in DMD is limited. Further studies of this model may, however, shed light on the phenomenon of catch-up growth.This article has an associated First Person interview with the first author of the paper.

Fractures and Linear Growth in a Nationwide Cohort of Boys With Duchenne Muscular Dystrophy With and Without Glucocorticoid Treatment: Results From the UK NorthStar Database.

Importance: Based on studies with relatively small sample size, fragility fractures are commonly reported in glucocorticoid (GC)-treated boys with Duchenne muscular dystrophy (DMD). Objective: To determine the fracture burden and growth impairment in a large contemporary cohort of boys with DMD in the United Kingdom and in relation to GC regimen. Design, Setting, and Participants: A retrospective review of fracture morbidity and growth from 832 boys with DMD in the UK NorthStar database (2006-2015), which systematically captures information from 23 participating centers. A total of 564 boys had more than 1 visit. No numbers of boys who refused were collected, but informal data from 2 centers in London and from Scotland show that refusal is very low. Data were analyzed between October 2006 and October 2015. Main Outcomes and Measures: Fracture incidence rate per 10 000 person-years was determined. Cox regression analysis was used to identify factors associated with first fracture. Results: Median age at baseline was 6.9 years (interquartile range, 4.9-7.2 years). At baseline, new fractures were reported in 7 of 564 participants (1.2%). During a median follow-up of 4 years (interquartile range, 2.0-6.0 years), incident fractures were reported in 156 of 564 participants (27.7%), corresponding to an overall fracture incidence rate of 682 per 10 000 person-years (95% CI, 579-798). The highest fracture incidence rate was observed in those treated with daily deflazacort at 1367 per 10 000 person-years (95% CI, 796-2188). After adjusting for age at last visit, mean hydrocortisone equivalent dose, mobility status, and bisphosphonate use prior to first fracture, boys treated with daily deflazacort had a 16.0-fold increased risk for first fracture (95% CI, 1.4-180.8; P = .03). Using adjusted regression models, change in height standard deviation scores was -1.6 SD lower (95% CI, -3.0 to -0.1; P = .03) in those treated with daily deflazacort compared with GC-naive boys, whereas there were no statistical differences in the other GC regimen. Conclusions and Relevance: In this large group of boys with DMD with longitudinal data, we document a high fracture burden. Boys treated with daily deflazacort had the highest fracture incidence rate and the greatest degree of linear growth failure. Clinical trials of primary bone protective therapies and strategies to improve growth in boys with DMD are urgently needed, but stratification based on GC regimen may be necessary.

Skeletal Fragility and Its Clinical Determinants in Children With Type 1 Diabetes.

CONTEXT: Type 1 diabetes (T1D) is associated with an increased fracture risk at all ages. OBJECTIVE: To understand the determinants of bone health and fractures in children with T1D. DESIGN: Case-control study of children with T1D on bone-turnover markers, dual-energy X-ray absorptiometry, and 3 Tesla-MRI of the proximal tibia to assess bone microarchitecture and vertebral marrow adiposity compared with age- and sex-matched healthy children. RESULTS: Thirty-two children with T1D at a median (range) age of 13.7 years (10.4, 16.7) and 26 controls, aged 13.8 years (10.2, 17.8), were recruited. In children with T1D, serum bone-specific alkaline phosphatase (BAP) SD score (SDS), C-terminal telopeptide of type I collagen SDS, and total body (TB) and lumbar spine bone mineral density (BMD) SDS were lower (all P < 0.05). Children with T1D also had lower trabecular volume [0.55 (0.47, 0.63) vs 0.59 (0.47, 0.63); P = 0.024], lower trabecular number [1.67 (1.56, 1.93) vs 1.82 (1.56, 1.99); P = 0.004], and higher trabecular separation [0.27 (0.21, 0.32) vs 0.24 (0.20, 0.33); P = 0.001] than controls. Marrow adiposity was similar in both groups (P = 0.25). Bone formation, as assessed by BAP, was lower in children with poorer glycemic control (P = 0.009) and who were acidotic at initial presentation (P = 0.017) but higher in children on continuous subcutaneous insulin infusion (P = 0.025). Fractures were more likely to be encountered in children with T1D compared with controls (31% vs 19%; P< 0.001). Compared with those without fractures, the T1D children with a fracture history had poorer glycemic control (P = 0.007) and lower TB BMD (P < 0.001) but no differences in bone microarchitecture. CONCLUSION: Children with T1D display a low bone-turnover state with reduced bone mineralization and poorer bone microarchitecture.