Impact of Type 1 Diabetes Mellitus on Skeletal Integrity and Strength in Adolescents as Assessed by HRpQCT

Bone properties in persons with type 1 diabetes and healthy controls - A cross-sectional study

BACKGROUND

The risk of fractures is increased in persons with type 1 diabetes (T1D) and assessment of bone health has been included in the 2024 updated Standards of Care by The American Diabetes Association (ADA). Previous studies have found that in T1D bone metabolism, mineral content, microstructure, and strength diverge from that of persons without diabetes. However, a clear description of a T1D bone phenotype has not yet been established. We investigated bone mechanical properties and microstructure in T1D compared with healthy controls. For the potential future introduction of additional bone measures in the clinical fracture risk assessment, we aimed to assess any potential associations between various measures related to bone indices in subjects with T1D.

METHODS

We studied human bone indices in a clinical cross-sectional setup including 111 persons with early-onset T1D and 37 sex- and age-matched control persons. Participants underwent hip and spine DXA scans for bone mineral density (BMD) of the femoral neck (FN), total hip (TH), and lumbar spine (LS), and TBS evaluation, microindentation of the tibial shaft for Bone Material Strength index (BMSi), and high-resolution periphery quantitative computed tomography (HRpQCT) of the distal radius and tibia for volumetric BMD (vBMD) and structural measures of trabecular and cortical bone. Results are reported as means with (standard deviation) or (95 % confidence intervals (CI)), medians with [interquartile range], and differences are reported with (95 % CI).

RESULTS

The study included 148 persons aged 20 to 75 years with a median age of 43.2 years. The T1D group who had all been diagnosed with T1D before the age of 18 years demonstrated values of HbA1c ranging from 39 to 107 mmol/mol and a median HbA1c of 57 mmol/mol. The BMD did not differ between groups (the mean difference in FN-BMD was 0.026 g/cm2 (-0.026; 0.079), p = 0.319) and the median BMSi was comparable in the two groups (79.2 [73.6; 83.8] in the T1D group compared with 77.9 [70.5, 86.1] in the control group). Total and trabecular vBMD (Tb.vBMD), cortical thickness (Ct.Th), and trabecular thickness (Tb.Th) of both radius and tibia were lower in participants with T1D. The mean Tb.vBMD at the radius was 143.6 (38.5) mg/cm3 in the T1D group and 171.5 (37.7) mg/cm3 in the control group, p < 0.001. The mean Ct. Thd of the radius was 0.739 mm (0.172) in the T1D group and 0.813 (0.188) in the control group, p = 0.044. Crude linear regressions revealed limited agreement between BMSi and Tb.vBMD (p = 0.010, r2 = 0.040 at the radius and p = 0.008, r2 = 0.040 at the tibia and between BMSi and the estimated failure load (FL) at the tibia (p < 0.001, r2 = 0.090). There were no significant correlations between BMSi and Ct.Th. TBS correlated with Tb.vBMD at the radius (p = 0.008, r2 = 0.044) and the tibia (p = 0.001, r2 = 0.069), and with the estimated FL at the distal tibia (p = 0.038, r2 = 0.026).

CONCLUSION

In this study, we examined the bones of persons with well-controlled, early-onset T1D. Compared with sex- and age-matched healthy control persons, we found reduced total and trabecular vBMD, as well as decreased trabecular and cortical thickness. These results suggest that a debut of T1D before reaching peak bone mass negatively impacts bone microarchitecture. No differences in areal BMD or BMSi were observed. Although the variations in total hip BMD reflect some variation in the vBMD, the reduction in trabecular bone mineral density was not captured by the DXA scan. Consequently, fracture risk may be underestimated when relying on DXA, and further research into fracture risk assessment in T1D is warranted.

Bone and muscle differences in children and adolescents with type 1 diabetes: The mediating role of physical activity

Children with type 1 diabetes (T1D) experience an increased risk of fracture, which may be related to altered bone development. We aimed to assess differences in bone, muscle and physical activity (PA), and explore if better muscle and PA measures would mitigate bone differences between children and adolescents with T1D and typically developing peers (TDP). We matched 56 children and adolescents with T1D (mean age 11.9 yrs) and 56 TDP (11.5 yrs) by sex and maturity from 171 participants with T1D and 66 TDP (6-17 yrs). We assessed the distal radius and tibia with high-resolution peripheral quantitative computed tomography (HR-pQCT), and the radius and tibia shaft bone and muscle with pQCT. We also measured muscle function from force-related measures in neuromuscular performance tests (push-up, grip test, countermovement and long jump). We compared PA based on questionnaire scores and accelerometers between groups. Bone, muscle, and neuromuscular performance measures were compared using MANOVA. We used mediation to explore the role of PA and muscle in bone differences. Children and adolescents with T1D had 6-10 % lower trabecular density, bone volume fraction, thickness and number at both distal radius and tibia, and 11 % higher trabecular separation at the distal radius than TDP. They also had 3-16 % higher cortical and tissue mineral density, and cortical thickness at the distal radius, 5-7 % higher cortical density and 1-3 % higher muscle density at both shaft sites compared to TDP. PA mediated the between-group difference in trabecular number (indirect effect -0.04) at the distal radius. Children and adolescents with T1D had lower trabecular bone density and deficits in trabecular micro-architecture, but higher cortical bone density and thickness at the radius and tibia compared to TDP. They engaged in less PA but had comparable muscle measures to those of TDP. PA participation may assist in mitigating deficit in trabecular number observed in children and adolescents with T1D.

Adolescent girls with type 1 diabetes develop changes in bone prior to evidence of clinical neuropathy

CONTEXT

Neuropathy and fracture are prevalent complications of type 1 diabetes (T1D). Although correlated in the clinical literature, it remains unknown whether neuropathy contributes to the initiation of bone loss at the earliest stages of disease.

METHODS

We performed a single-center, cross-sectional study to quantify parameters of nerve and bone health in adolescent girls with T1D (n=21) and associated controls (n=12). Groups were well matched for age, height, strength, and physical activity.

RESULTS

By HR-pQCT, participants with T1D had lower trabecular bone volume fraction at the distal radius (-14.6%, p-adj=0.095) and the tibia (-12.8%, p-adj=0.017) and decreased trabecular thickness (-8.3% radius, p-adj=0.007; -7.5% tibia, p-adj=0.034) after adjustment for body size. In the tibia only, cortical bone mineral density was increased by 8.6% (p-adj=0.024) and porosity was decreased by 52.9% with T1D (p-adj=0.012). There were no significant differences in bone density by DXA. Participants with T1D also had lower circulating levels of osteocalcin (-30%, p=0.057), and type I collagen cross-linked C-telopeptide (-36%, p=0.035), suggesting low bone formation and turnover in T1D. Based on the Michigan Neuropathy Screening Instrument, 9.5% of those with T1D had clinical evidence of diabetic peripheral neuropathy. However, consideration of neuropathy status failed to explain the widespread T1D-associated changes in bone.

CONCLUSION

Our study defines early deficits in trabecular bone microarchitecture, decreased cortical porosity in the tibia, and suppression of biomarkers of bone turnover in adolescent girls with T1D, prior to the onset of symptomatic peripheral neuropathy. These findings inform our understanding of the rapid progression of skeletal disease in young girls with T1D and suggests that early detection and management strategies may help to prevent fracture and related co-morbidities later in life.

Bone health in young adults with type 1 diabetes and progressive eGFR decline

BACKGROUND

Type 1 Diabetes (T1D) is associated with increased risk of fractures, worsened by presence of microvascular complications. This study's objective is to determine the impact of progressive decline in estimated glomerular filtration rate (eGFR) on bone biomarkers and bone microarchitecture in youth with T1D.

METHODS

Slopes of eGFR were calculated using measures obtained at four timepoints from adolescence to young adulthood. Participants were identified as eGFR decliners if eGFR decreased ≥ 3ml/min/1.73m2/year. Bone health was assessed in young adulthood by high resolution peripheral quantitative computed tomography (HRpQCT Xtreme CTII) and bone biomarkers; osteocalcin, procollagen 1 intact n-terminal pro-peptide (P1NP), c-terminal telopeptide (CTX), and bone specific alkaline phosphatase. The relationship between diabetes duration, glycated hemoglobin, body mass index (BMI) and vitamin D level on bone biomarkers and microarchitecture was evaluated. Linear regression analysis was used for the statistical analysis in this study.

RESULTS

Ninety-nine study participants were studied with longitudinal evaluation of eGFR over 7.4 ± 1.0 years with mean age of 14.7 ± 1.7 years at baseline. Cross sectional evaluation of bone was performed at 21.3 ± 2.1 years. 44% participants had eGFR decline and showed 5% higher cortical porosity diameter than non-decliners (p = 0.035). Greater diabetes duration was associated with higher trabecular separation (p = 0.004) and lower trabecular number (p = 0.01). Higher level of 25 hydroxy-vitamin D was associated with lower trabecular separation (p = 0.01). Elevated glycated hemoglobin (p = 0.0008) and BMI (p = 0.009), were associated with lower markers of bone formation.

CONCLUSION

Mild increase in cortical porosity diameter was found in youth with T1D and eGFR decline, however, overall measures of bone microarchitecture on HR-pQCT were similar between both groups and there were no statistically significant changes in bone biomarkers. Hence, skeletal impairments were limited in youth with different eGFR trajectories near peak bone mass. Longitudinal HR-pQCT studies are needed to further understand the impact of eGFR decline on bone microarchitecture. Optimal glycemic control, normal BMI and vitamin D status were supported by this study as important markers for good bone health.

Insulin-like growth factor 1 and sex hormones for assessment of anthropometric and pubertal growth of Egyptian children and adolescents with type 1 diabetes mellitus (single center study)

BACKGROUND

This study aimed to assess the anthropometric measures and pubertal growth of children and adolescents with Type 1 diabetes mellitus (T1DM) and to detect risk determinants affecting these measures and their link to glycemic control.

PATIENTS AND METHODS

Two hundred children and adolescents were assessed using anthropometric measurements. Those with short stature were further evaluated using insulin-like growth factor 1 (IGF-1), bone age, and thyroid profile, while those with delayed puberty were evaluated using sex hormones and pituitary gonadotropins assay.

RESULTS

We found that 12.5% of our patients were short (height SDS < -2) and IGF-1 was less than -2 SD in 72% of them. Patients with short stature had earlier age of onset of diabetes, longer duration of diabetes, higher HbA1C and urinary albumin/creatinine ratio compared to those with normal stature (p < 0.05). Additionally, patients with delayed puberty had higher HbA1c and dyslipidemia compared to those with normal puberty (p < 0.05). The regression analysis revealed that factors associated with short stature were; age at diagnosis, HbA1C > 8.2, and albumin/creatinine ratio > 8 (p < 0.05).

CONCLUSION

Children with uncontrolled T1DM are at risk of short stature and delayed puberty. Diabetes duration and control seem to be independent risk factors for short stature.

Total Calcium Intake Is Associated With Trabecular Bone Density in Adolescent Girls With Type 1 Diabetes

Type 1 diabetes (T1D) confers an increased risk of fracture and is associated with lower bone mineral density (BMD) and altered microarchitecture compared with controls. Adequate calcium (Ca) intake promotes bone mineralization, thereby increasing BMD. The objective of this analysis was to evaluate the associations of total daily Ca intake with bone outcomes among youth with T1D. This was a cross-sectional analysis of girls ages 10-16 years with (n = 62) and without (n = 60) T1D. We measured Ca intake with a validated food-frequency questionnaire and BMD, microarchitecture, and strength estimates with dual-energy X-ray absorptiometry and high-resolution peripheral quantitative computed tomography. Total daily Ca intake did not differ between groups (950 ± 488 in T1D versus 862 ± 461 mg/d in controls, p = 0.306). Serum 25OHD was lower in T1D (26.3 ± 7.6 versus 32.6 ± 9.0 ng/mL, p = <0.001), and parathyroid hormone (PTH) was higher in T1D (38.9 ± 11 versus 33.4 ± 9.7 pg/mL, p = 0.004). Trabecular volumetric BMD and thickness at the tibia were lower in T1D (p = 0.013, p = 0.030). Ca intake correlated with trabecular BMD at the radius and tibia among T1D participants (β = 0.27, p = 0.047, and β = 0.28, p = 0.027, β = 0.28, respectively) but not among controls (pinteraction = 0.009 at the radius, pinteraction = 0.010 at the tibia). Similarly, Ca intake was associated with estimated failure load at the tibia in T1D but not control participants (p = 0.038, β = 0.18; pinteraction = 0.051). We observed the expected negative association of Ca intake with parathyroid hormone in controls (p = 0.022, β = -0.29) but not in T1D participants (pinteraction = 0.022). Average glycemia as measured by hemoglobin A1c did not influence the relationship of Ca and PTH among participants with T1D (pinteraction = 0.138). These data suggest that youth with T1D may be particularly vulnerable to dietary Ca insufficiency. Increasing Ca intake may be an effective strategy to optimize bone health in this population. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC. on behalf of American Society for Bone and Mineral Research.

High-resolution peripheral quantitative computed tomography: research or clinical practice?

High-resolution peripheral quantitative CT (HR-pQCT) is a low-dose three-dimensional imaging technique, originally developed for in vivo assessment of bone microarchitecture at the distal radius and tibia in osteoporosis. HR-pQCT has the ability to discriminate trabecular and cortical bone compartments, providing densitometric and structural parameters. At present, HR-pQCT is mostly used in research settings, despite evidence showing that it may be a valuable tool in osteoporosis and other diseases. This review summarizes the main applications of HR-pQCT and addresses the limitations that currently prevent its integration into routine clinical practice. In particular, the focus is on the use of HR-pQCT in primary and secondary osteoporosis, chronic kidney disease (CKD), endocrine disorders affecting bone, and rare diseases. A section on novel potential applications of HR-pQCT is also present, including assessment of rheumatic diseases, knee osteoarthritis, distal radius/scaphoid fractures, vascular calcifications, effect of medications, and skeletal muscle. The reviewed literature seems to suggest that a more widespread implementation of HR-pQCT in clinical practice would offer notable opportunities. For instance, HR-pQCT can improve the prediction of incident fractures beyond areal bone mineral density provided by dual-energy X-ray absorptiometry. In addition, HR-pQCT may be used for the monitoring of anti-osteoporotic therapy or for the assessment of mineral and bone disorder associated with CKD. Nevertheless, several obstacles currently prevent a broader use of HR-pQCT and would need to be targeted, such as the small number of installed machines worldwide, the uncertain cost-effectiveness, the need for improved reproducibility, and the limited availability of reference normative data sets.

Relationship between risk factors for impaired bone health and HR-pQCT in young adults with type 1 diabetes

OBJECTIVE

In type 1 diabetes, risk factors associated with impaired bone health contribute to increased risk of fracture. The aim of this study was to (1): compare the high-resolution peripheral quantitative computed tomography (HR-pQCT) parameters of young adults with type 1 diabetes with those of healthy controls (2), identify sex differences, and (3) evaluate the association between diabetes and bone health risk factors, with HR-pQCT.

METHODS

This is a cross-sectional study in young Canadian adults with childhood onset type 1 diabetes. Z-scores were generated for HR-pQCT parameters using a large healthy control database. Diet, physical activity, BMI, hemoglobin A1C (A1C) and bone health measures were evaluated, and associations were analyzed using multivariate regression analysis.

RESULTS

Eighty-eight participants (age 21 ± 2.2 years; 40 males, 48 females, diabetes duration 13.9 ± 3.4 years) with type 1 diabetes were studied. Low trabecular thickness and elevated cortical geometry parameters were found suggesting impaired bone quality. There were no sex differences. Significant associations were found: Vitamin D (25(OH)D) with trabecular parameters with possible synergy with A1C, parathyroid hormone with cortical parameters, BMI with cortical bone and failure load, and diabetes duration with trabecular area.

CONCLUSIONS

Our data suggests impairment of bone health as assessed by HR-pQCT in young adults with type 1 diabetes. Modifiable risk factors were associated with trabecular and cortical parameters. These findings imply that correction of vitamin D deficiency, prevention and treatment of secondary hyperparathyroidism, and optimization of metabolic control may reduce incident fractures.

A narrative review of diabetic bone disease: Characteristics, pathogenesis, and treatment

Recently, the increasing prevalence of diabetes mellitus has made it a major chronic illness which poses a substantial threat to human health. The prevalence of osteoporosis among patients with diabetes mellitus has grown considerably. Diabetic bone disease is a secondary osteoporosis induced by diabetes mellitus. Patients with diabetic bone disease exhibit variable degrees of bone loss, low bone mineral density, bone microarchitecture degradation, and increased bone fragility with continued diabetes mellitus, increasing their risk of fracture and impairing their ability to heal after fractures. At present, there is extensive research interest in diabetic bone disease and many significant outcomes have been reported. However, there are no comprehensive review is reported. This review elaborates on diabetic bone disease in the aspects of characteristics, pathogenesis, and treatment.

Meta-analysis of Diabetes Mellitus-Associated Differences in Bone Structure Assessed by High-Resolution Peripheral Quantitative Computed Tomography

PURPOSE OF REVIEW

Diabetes mellitus is defined by elevated blood glucose levels caused by changes in glucose metabolism and, according to its pathogenesis, is classified into type 1 (T1DM) and type 2 (T2DM) diabetes mellitus. Diabetes mellitus is associated with multiple degenerative processes, including structural alterations of the bone and increased fracture risk. High-resolution peripheral computed tomography (HR-pQCT) is a clinically applicable, volumetric imaging technique that unveils bone microarchitecture in vivo. Numerous studies have used HR-pQCT to assess volumetric bone mineral density and microarchitecture in patients with diabetes, including characteristics of trabecular (e.g. number, thickness and separation) and cortical bone (e.g. thickness and porosity). However, study results are heterogeneous given different imaging regions and diverse patient cohorts.

RECENT FINDINGS

This meta-analysis assessed T1DM- and T2DM-associated characteristics of bone microarchitecture measured in human populations in vivo reported in PubMed- and Embase-listed publications from inception (2005) to November 2021. The final dataset contained twelve studies with 516 participants with T2DM and 3067 controls and four studies with 227 participants with T1DM and 405 controls. While T1DM was associated with adverse trabecular characteristics, T2DM was primarily associated with adverse cortical characteristics. These adverse effects were more severe at the radius than the load-bearing tibia, indicating increased mechanical loading may compensate for deleterious bone microarchitecture changes and supporting mechanoregulation of bone fragility in diabetes mellitus. Our meta-analysis revealed distinct predilection sites of bone structure aberrations in T1DM and T2DM, which provide a foundation for the development of animal models of skeletal fragility in diabetes and may explain the uncertainty of predicting bone fragility in diabetic patients using current clinical algorithms.

Bone deficits in children and youth with type 1 diabetes: A systematic review and meta-analysis

Deficits in bone mineral and weaker bone structure in children with type 1 diabetes (T1D) may contribute to a lifelong risk of fracture. However, there is no meta-analysis comparing bone properties beyond density between children with T1D and typically developing children (TDC). This meta-analysis aimed to assess differences and related factors in bone mineral content (BMC), density, area, micro-architecture and estimated strength between children with T1D and TDC. We systematically searched MEDLINE, Embase, CINAHL, Web of Science, Scopus, Cochrane Library databases, and included 36 in the meta-analysis (2222 children and youth with T1D, 2316 TDC; mean age ≤18 yrs., range 1-24). We estimated standardized mean differences (SMD) using random-effects models and explored the role of age, body size, sex ratio, disease duration, hemoglobin A1c in relation to BMC and areal density (aBMD) SMD using meta-regressions. Children and youth with T1D had lower total body BMC (SMD: -0.21, 95% CI: -0.37 to -0.05), aBMD (-0.30, -0.50 to -0.11); lumbar spine BMC (-0.17, -0.28 to -0.06), aBMD (-0.20, -0.32 to -0.08), bone mineral apparent density (-0.30, -0.48 to -0.13); femoral neck aBMD (-0.21, -0.33 to -0.09); distal radius and tibia trabecular density (-0.38, -0.64 to -0.12 and -0.35, -0.51 to -0.18, respectively) and bone volume fraction (-0.33, -0.56 to -0.09 and -0.37, -0.60 to -0.14, respectively); distal tibia trabecular thickness (-0.41, -0.67 to -0.16); and tibia shaft cortical content (-0.33, -0.56 to -0.10). Advanced age was associated with larger SMD in total body BMC (-0.13, -0.21 to -0.04) and aBMD (-0.09; -0.17 to -0.01) and longer disease duration with larger SMD in total body aBMD (-0.14; -0.24 to -0.04). Children and youth with T1D have lower BMC, aBMD and deficits in trabecular density and micro-architecture. Deficits in BMC and aBMD appeared to increase with age and disease duration. Bone deficits may contribute to fracture risk and require attention in diabetes research and care. STUDY REGISTRATION: PROSPERO (CRD42020200819).

The use of quantitative ultrasound in a tertiary-level children hospital: role in the follow-up of chronically ill patients

PURPOSE

To evaluate the use of QUS for the bone status assessment in children cared because of a chronic disease such as: inherited metabolic disorder, kidney disease and endocrine defect and considered by the attending physician as at specific risk.

METHODS

QUS outputs were calculated for each disorder and compared to: sex, age, Tanner stage, Z-score for height, weight and BMI (body mass index).

RESULTS

One-hundred-sixty-eight subjects aged between 3.5 and 18 years met the inclusion criteria. The overall bone quality indexes were under the normal range in all the groups considered. Impairment of bone quality parameters was more evident in the group of patients with inherited metabolic disorders, in which 65% of patients in charge were studied by QUS. Older age and sexual development were associated with less pronounced bone quality impairment, as measured by QUS, in the vast majority of conditions. Overall, the diseases for which the prediction of outcome was the strongest were: hyperphenylalaninemia, nephrotic syndrome and insulin dependent diabetes mellitus.

CONCLUSIONS

QUS is capable to provide information on skeletal status in children. Initial evaluation by QUS may allow defining patients with chronic disorders who deserve further, more invasive diagnostic studies. Inherited metabolic disorders warrant specific attention and strict monitoring for their potential effect on bone.

Impact of Type 1 Diabetes Mellitus on Bone Health in Children

This paper gives an overview of the impact of type 1 diabetes on bone health in children and adolescents. Firstly, we analyse studies using dual X-ray absorptiometry to assess bone mineral content and bone mineral density. Then, we discuss modern, non-invasive techniques including peripheral quantitative computer tomography (pQCT) and high-resolution pQCT for the detailed assessment of bone health aspects including bone mass, bone geometry, bone microarchitecture, and bone strength. Thereafter, we explore some of the mechanisms that are responsible for diabetic bone disease in children, like low bone turnover and high sclerostin levels. Finally, we summarize some of the evidence for the importance of microvascular disease in the pathophysiology of diabetic bone disease.

Insulin resistance and skeletal health

PURPOSE OF REVIEW

Bone fragility is a complication of type 2 diabetes (T2D), and insulin resistance is suspected to contribute to diabetes-related bone deficits. This article provides an overview of emerging clinical research involving insulin resistance and bone health by summarizing recent publications, identifying existing knowledge gaps, and suggesting 'next steps' for this evolving field of research.

RECENT FINDINGS

Clinical studies in children and adults report greater bone density in people with increased insulin resistance, but these associations are often attenuated when adjusting for body size. Advancements in bone imaging methods allow for assessment of nuanced characteristics of bone quality and strength that extend beyond standard bone mineral density assessment methods. For example, several recent studies focusing on lumbar spine trabecular bone score, a relatively new measure of trabecular bone quality from dual-energy X-ray absorptiometry, have reported generally consistent inverse associations with insulin resistance. Longitudinal studies using advanced imaging methods capable of evaluating trabecular bone microstructure and strength, such as high-resolution peripheral quantitative computed tomography, are lacking. Studies in younger individuals are sparse, but emerging data suggest that peak bone mass attainment might be threatened by diabetes progression, and increased visceral fat, suppressed muscle-bone unit, advanced glycation end-products, sedentary lifestyle, and poor diet quality might contribute to diabetes effects on bone. Prospective studies during the transition from adolescence to young adulthood are required.

SUMMARY

Insulin resistance is a main feature of T2D, which is suspected to contribute to subclinical diabetes-related threats to bone health. Future clinical studies should focus on the critical years surrounding peak bone mass and peak bone strength attainment using contemporary imaging techniques.

Imaging techniques to study diabetic bone disease

PURPOSE OF REVIEW

This review article presents the most recent research on bone fragility in individuals with diabetes from a medical imaging perspective.

RECENT FINDINGS

The widespread availability of dual-energy X-ray absorptiometry (DXA) and trabecular bone score (TBS) software has led to recent assessments of bone fragility with this texture parameter in several studies of type 2 diabetes mellitus (T2D), but in few of type 1 diabetes mellitus (T1D). Although most studies show a trend of reduced TBS values in T2D independent of areal bone mineral density (aBMD) of the lumbar spine, some studies also show the limitations of TBS in both T2D and T1D. Given the limitations of DXA to assess bone strength and investigate the etiology of bone fragility in diabetes, more investigators are incorporating three-dimensional (3D) medical imaging techniques in their studies. Recent use of 3D medical imaging to assess bone fragility in the setting of diabetes has been mostly limited to a few cross-sectional studies predominantly incorporating high-resolution peripheral quantitative computed tomography (HR-pQCT). Although HR-pQCT studies indicate higher tibial cortical porosity in subjects with T2D, results are inconsistent in T1D due to differences in study designs, sample sizes, and subject characteristics, among other factors. With respect to central CT, recent studies support a previous finding in the literature indicating femoral neck geometrical impairments in subjects with T2D and provide encouraging results for the incorporation of finite element analysis (FEA) to assess bone strength in studies of T2D. In the recent literature, there are no studies assessing bone fragility in T1D with QCT, and only two studies used pQCT reporting tibial and radial impairments in young women and children with T1D, respectively. Magnetic resonance imaging (MRI) has not been recently used in diabetic studies of bone fragility.

SUMMARY

As bone fragility in diabetes is not explained by DXA-derived aBMD and given the limitations of cross-sectional studies, it is imperative to use 3D imaging techniques for longitudinal assessments of the density, quality, and microenvironment of bone to improve our understanding of the effects of diabetes on bone and reduce the risk of fracture in this large and vulnerable population of subjects with diabetes.

Higher Body Fat in Children and Adolescents With Type 1 Diabetes-A Systematic Review and Meta-Analysis

Aims

Higher prevalence of overweight and obesity in children and adolescents with type 1 diabetes (T1D) suggests alterations are required in body composition. However, differences in body composition between children with T1D and typically developing children (TDC) have not been synthesized using meta-analysis. Therefore, we conducted a systematic review and meta-analysis to compare body composition between children with T1D and TDC, and to explore the role of disease and non-disease related factors in potential body composition differences.

Methods

Studies were performed comparing dual-energy x-ray absorptiometry-acquired total body fat and lean mass, absolute (kg) and relative (%) values, between children with T1D and TDC. We reported mean differences with 95% confidence intervals (CI) from meta-analysis and relative between-group %-differences. We used meta-regression to explore the role of sex, age, height, body mass, body mass index, Hemoglobin A1c, age of onset, disease duration, and insulin dosage in the potential body composition differences between children with T1D and TDC, and subgroup analysis to explore the role of geographic regions (p < 0.05).

Results

We included 24 studies (1,017 children with T1D, 1,045 TDC) in the meta-analysis. Children with T1D had 1.2 kg more fat mass (kg) (95%CI 0.3 to 2.1; %-difference = 9.3%), 2.3% higher body fat % (0.3-4.4; 9.0%), but not in lean mass outcomes. Age of onset (β = -2.3, -3.5 to -1.0) and insulin dosage (18.0, 3.5-32.6) were negatively and positively associated with body fat % mean difference, respectively. Subgroup analysis suggested differences among geographic regions in body fat % (p < 0.05), with greater differences in body fat % from Europe and the Middle East.

Conclusion

This meta-analysis indicated 9% higher body fat in children with T1D. Earlier diabetes onset and higher daily insulin dosage were associated with body fat % difference between children with T1D and TDC. Children with T1D from Europe and the Middle East may be more likely to have higher body fat %. More attention in diabetes research and care toward body composition in children with T1D is needed to prevent the early development of higher body fat, and to minimize the cardiovascular disease risk and skeletal deficits associated with higher body fat.

Bone Microarchitecture and Strength in Long-Standing Type 1 Diabetes

Type 1 diabetes (T1DM) is associated with an increased fracture risk, specifically at nonvertebral sites. The influence of glycemic control and microvascular disease on skeletal health in long-standing T1DM remains largely unknown. We aimed to assess areal (aBMD) and volumetric bone mineral density (vBMD), bone microarchitecture, bone turnover, and estimated bone strength in patients with long-standing T1DM, defined as disease duration ≥25 years. We recruited 59 patients with T1DM (disease duration 37.7 ± 9.0 years; age 59.9 ± 9.9 years.; body mass index [BMI] 25.5 ± 3.7 kg/m² ; 5-year median glycated hemoglobin [HbA1c] 7.1% [IQR 6.82-7.40]) and 77 nondiabetic controls. Dual-energy X-ray absorptiometry (DXA), high-resolution peripheral quantitative computed tomography (HRpQCT) at the ultradistal radius and tibia, and biochemical markers of bone turnover were assessed. Group comparisons were performed after adjustment for age, gender, and BMI. Patients with T1DM had lower aBMD at the hip (p < 0.001), distal radius (p = 0.01), lumbar spine (p = 0.04), and femoral neck (p = 0.05) as compared to controls. Cross-linked C-telopeptide (CTX), a marker of bone resorption, was significantly lower in T1DM (p = 0.005). At the distal radius there were no significant differences in vBMD and bone microarchitecture between both groups. In contrast, patients with T1DM had lower cortical thickness (estimate [95% confidence interval]: -0.14 [-0.24, -0.05], p < 0.01) and lower cortical vBMD (-28.66 [-54.38, -2.93], p = 0.03) at the ultradistal tibia. Bone strength and bone stiffness at the tibia, determined by homogenized finite element modeling, were significantly reduced in T1DM compared to controls. Both the altered cortical microarchitecture and decreased bone strength and stiffness were dependent on the presence of diabetic peripheral neuropathy. In addition to a reduced aBMD and decreased bone resorption, long-standing, well-controlled T1DM is associated with a cortical bone deficit at the ultradistal tibia with reduced bone strength and stiffness. Diabetic neuropathy was found to be a determinant of cortical bone structure and bone strength at the tibia, potentially contributing to the increased nonvertebral fracture risk. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Bone Fractures in Children and Young Adults With Type 1 Diabetes: Age Distribution, Fracture Location, and the Role of Glycemic Control

Type 1 diabetes (T1D) is a known risk factor for fractures, but the underlying pathophysiology is still not fully understood. This study aims to define age peaks and frequent fracture sites of children and young adults with T1D. Additionally, associations of fractures with metabolic and lifestyle factors as well as with additional complications in individuals with T1D were analyzed. A total of 750 individuals with T1D aged ≤25 years with fractures were matched to 3750 patients with T1D without fractures by demographics and insulin regimen. Hemoglobin A1c (HbA1c) values were compared using linear regression, and logistic regression was used to calculate odds ratios (OR) for fractures in individuals with acute complications and diseases. Median (Q1-Q3) age was 12.7 (9.9 to 14.9) years in individuals with fractures and 16.3 (12.6 to 17.8) years in the entire control group with 65% versus 53% males. Peak age for fractures was 7 to <15 years in males and 9 to <11 years in females, which is earlier than reported for the general population. HbA1c (%) was significantly higher in individuals with fractures than in controls (difference of estimated means: 0.26%; 95% confidence interval [CI] 0.07-0.46), especially in postpubertal females (0.68; 0.10-1.26). Significantly higher odds for fractures were observed in individuals with severe hypoglycemia (OR = 1.90; 95% CI 1.47-2.47), especially in prepubertal females (OR = 2.81; 1.21-6.52]) and postpubertal males (2.44; 1.11-5.38), celiac disease (2.02; 1.67-2.45), and with a history of smoking (1.38; 1.02-1.88). The age peak of fractures seems to be earlier in T1D than in the general population. Poor glycemic control is related to fractures, even before puberty. Associations of HbA1c and severe hypoglycemia with fractures highly depend on age and sex. © 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Bone accrual in children and adolescents with type 1 diabetes: current knowledge and future directions

PURPOSE OF REVIEW

Skeletal fragility is now recognized as a significant complication of type 1 diabetes (T1D). Many patients with T1D develop the disease in childhood and prior to the attainment of peak bone mass and strength. This manuscript will review recent studies investigating the effects of T1D on skeletal development.

RECENT FINDINGS

Mild-to-moderate deficits in bone density, structure, and mineral accrual were reported early in the course of T1D in some but not all studies. Childhood-onset disease was associated with a more severe skeletal phenotype in some adult studies. Lower than expected bone mass for muscle size was been described. Hemoglobin A1c was negatively associated with bone density and structure in several studies, though the mechanism was not clear.

SUMMARY

The use of advanced imaging techniques has shown that the adverse effects of T1D on the developing skeleton extend beyond bone density to include abnormalities in bone size, shape, microarchitecture, and strength. Despite these gains, a uniform understanding of the pathophysiology underlying skeletal fragility in this disorder remains elusive. Longitudinal studies, especially in association with interventions to reduce hyperglycemia or improve muscle strength, are needed to inform bone healthcare in T1D.

Critical review of bone health, fracture risk and management of bone fragility in diabetes mellitus

The risk of fracture is increased in both type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM). However, in contrast to the former, patients with T2DM usually possess higher bone mineral density. Thus, there is a considerable difference in the pathophysiological basis of poor bone health between the two types of diabetes. Impaired bone strength due to poor bone microarchitecture and low bone turnover along with increased risk of fall are among the major factors behind elevated fracture risk. Moreover, some antidiabetic medications further enhance the fragility of the bone. On the other hand, antiosteoporosis medications can affect the glucose homeostasis in these patients. It is also difficult to predict the fracture risk in these patients because conventional tools such as bone mineral density and Fracture Risk Assessment Tool score assessment can underestimate the risk. Evidence-based recommendations for risk evaluation and management of poor bone health in diabetes are sparse in the literature. With the advancement in imaging technology, newer modalities are available to evaluate the bone quality and risk assessment in patients with diabetes. The purpose of this review is to explore the pathophysiology behind poor bone health in diabetic patients. Approach to the fracture risk evaluation in both T1DM and T2DM as well as the pragmatic use and efficacy of the available treatment options have been discussed in depth.

The Role of Irisin in Exercise-Mediated Bone Health

Exercise training promotes physical and bone health, and is the first choice of non-drug strategies that help to improve the prognosis and complications of many chronic diseases. Irisin is a newly discovered peptide hormone that modulates energy metabolism and skeletal muscle mass. Here, we discuss the role of irisin in bone metabolism via exercise-induced mechanical forces regulation. In addition, the role of irisin in pathological bone loss and other chronic diseases is also reviewed. Notably, irisin appears to be a key determinant of bone mineral status and thus may serve as a novel biomarker for bone metabolism. Interestingly, the secretion of irisin appears to be mediated by different forms of exercise and pathological conditions such as diabetes, obesity, and inflammation. Understanding the mechanism by which irisin is regulated and how it regulates skeletal metabolism via osteoclast and osteoblast activities will be an important step toward applying new knowledge of irisin to the treatment and prevention of bone diseases such as osteolysis and other chronic disorders.