Bone turnover markers in children and adolescents with type 1 diabetes-A systematic review

Bone metabolism in diabetes: a clinician's guide to understanding the bone-glucose interplay

Skeletal fragility is an increasingly recognised, but poorly understood, complication of both type 1 and type 2 diabetes. Fracture risk varies according to skeletal site and diabetes-related characteristics. Post-fracture outcomes, including mortality risk, are worse in those with diabetes, placing these people at significant risk. Each fracture therefore represents a sentinel event that warrants targeted management. However, diabetes is a very heterogeneous condition with complex interactions between multiple co-existing, and highly correlated, factors that preclude a clear assessment of the independent clinical markers and pathophysiological drivers for diabetic osteopathy. Additionally, fracture risk calculators and routinely used clinical bone measurements generally underestimate fracture risk in people with diabetes. In the absence of dedicated prospective studies including detailed bone and metabolic characteristics, optimal management centres around selecting treatments that minimise skeletal and metabolic harm. This review summarises the clinical landscape of diabetic osteopathy and outlines the interplay between metabolic and skeletal health. The underlying pathophysiology of skeletal fragility in diabetes and a rationale for considering a diabetes-based paradigm in assessing and managing diabetic bone disease will be discussed.

Glycemic control and study of lipid and bone metabolism in type 1 diabetic children

Introduction. Type 1 diabetes mellitus is considered one of the most common chronic diseases of childhood. It is a high-risk factor for developing early cardiovascular disease and it also affects bone health. Objective. To describe demographic characteristics and biochemical parameters of a population of children with type 1 diabetes, evaluated in the pediatric diabetes unit of a tertiary Spanish hospital. Materials and methods. In this retrospective study, we determined metabolic, lipid, and bone parameters in 124 children with type 1 diabetes who were monitored in the pediatric diabetes unit of the Hospital Universitario Miguel Servet in Zaragoza (Spain) from May 2020 to July 2021. Results. Children with type 1 diabetes have worse metabolic control of the disease at puberty, but their lipid control is considered acceptable. We found an inverse correlation between bone formation markers and disease duration, as well as with metabolic control. Conclusion. Bone formation markers are inversely correlated with the percentage of glycated hemoglobin and diabetes evolution time. Patients’ lipid and bone profiles are more favorable when metabolic control of the disease is achieved.

Osteoporosis and diabetes - possible links and diagnostic difficulties

Objectives

In this review, the authors aimed to clarify the relationship between the occurrence of osteoporosis and diabetes, analyze the differences between the pathogenesis of osteoporosis in different types of diabetes and propose the most effective diagnostic strategy and fracture risk assessment in diabetic patients.

Material and methods

A analysis of publications in MEDLINE, COCHRANE and SCOPUS databases was performed, searching for reports on the diagnostics, fracture risk assessment, prevention, and treatment of osteoporosis in patients with diabetes mellitus (DM) published in the years 2016-2022. The key words for the search were: diabetes, osteoporosis, and low-energy fracture.

Results

Bone complications of T1DM are more severe than T2DM, because of the lack of anabolic effect of insulin on bones. In T2DM the risk of fractures is elevated; however, identifying the mechanisms underlying the increased risk of fractures in T2DM is not clear. The FRAX tool is not appropriate for assessing the fracture risk in young patients with T1DM. It is quite useful in older patients with T2DM, but in these patients the calculated fracture risk may be underestimated. In T2DM the fracture risk often does not correspond to BMD value as measured by dual-energy X-ray absorptiometry (DXA). Diagnostic tools such as the trabecular bone score may play a significant role in this group of patients. Conclusions: Optimal strategies to identify and treat high risk individuals require further research and proper definition. The diagnostic criteria for osteoporosis should be clearly defined as well as fracture risk assessment and choice of anti-osteoporotic medication. In all cases of secondary osteoporosis, treatment of the underlying disease is the most important. The relationship between high risk of fractures and diabetes is inseparable, and its full understanding seems to be the key to effective management.

Broad application prospects of bone turnover markers in pediatrics

BACKGROUND

Bone turnover markers (BTMs) have been studied for application in clinical medicine. However, BTMs in children are challenging, and few studies explore these BTMs in children. The application of BTMs is complicated mainly due to pre-analytical factors, variable reference intervals of age- and sex-related BTMs for adolescents and children in different regions and laboratories. Therefore, laboratory testing of BTMs is critical for understanding pediatric bone development and metabolism, which provides additional information about bone development and diseases.

METHODS

Literature search was conducted using the MeSH term "child" combined with the terms that bone turnover markers such as "osteocalcin," "Procollagen type I N-terminal propeptide," "procollagen type I C-terminal propeptide," "osteocalcin," "N-terminal cross-linked telopeptide," and "C-terminal cross-linked telopeptide," Several databases including Web of Science, Google Scholar, and PubMed were searched to obtain the relevant studies.

RESULTS

BTMs represent the combined effects of skeletal development, growth, and remodeling in children, which can be used in clinical pediatrics to assist in the diagnosis and prognosis of bone metabolic disorders.

CONCLUSION

BTMs are clearly helpful for diagnosis and monitoring of bone growth and development as well as bone metabolic disorders.

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.

Diabetic Bone Disease and Diabetic Myopathy: Manifestations of the Impaired Muscle-Bone Unit in Type 1 Diabetes

Type 1 diabetes is associated with complications affecting muscle and bone, with diabetic bone disease and diabetic myopathy becoming increasingly reported in the past few decades. This review is aimed at succinctly reviewing the literature on the current knowledge regarding these increasingly identified and possibly interconnected complications on the musculoskeletal system. Furthermore, this review summarizes several nonmechanical factors that could be mediating the development and progression of premature musculoskeletal decline in this population and discusses preventative measures to reduce the burden of diabetes on the musculoskeletal system.

Stratification by Non-invasive Biomarkers of Non-alcoholic Fatty Liver Disease in Children

BACKGROUND

The spectrum of non-alcoholic fatty liver disease (NAFLD) ranges from isolated hepatic steatosis to non-alcoholic steatohepatitis to fibrosis. We aimed to introduce useful biomarkers released during liver inflammation and fibrogenesis that are easy to use in outpatient clinic and adjust to children to evaluate each NAFLD stage without biopsy.

METHODS

This prospective study included 60 patients aged under 19 years whose alanine aminotransferase (ALT) levels were elevated from March 2021. All patients were proven to have NAFLD by ultrasonography and laboratory work-up to exclude other causes of hepatitis. Fibroscan and additional laboratory tests for biomarkers [procollagen type1 amino-terminal propeptide (P1NP), osteocalcin, interleukin-6 (IL-6), and Mac-2 binding protein glycosylated isomer (M2BPGi)] were performed. Fibroscan-AST (FAST) score was used for the comparison of steatohepatitis and liver stiffness measurement (kPa) was used for the comparison of advanced fibrosis.

RESULTS

The biomarker that showed a significant difference between the FAST-positive and negative groups was the P1NP/osteocalcin ratio with a p-value of 0.008. The area under receiver operating characteristic (AUROC) of P1NP/osteocalcin ratio^*ALT values (values obtained through multivariate analysis) was 0.939 with the cut-off value of 305.38. The biomarkers that showed a significant difference between the LSM-positive and negative groups were IL-6 and M2BPGi with a p-values of 0.005 and <0.001. AUROC of IL-6 ^*AST values (values obtained through multivariate analysis) was 0.821 with the cut-off value of 228.15. M2BPGi showed a significant linear relationship with LSM in Pearson correlation analysis (Pearson correlation coefficient = 0.382; p = 0.003). The diagnostic capability of M2BPGi to evaluate advanced fibrosis showed an acceptable result (AUROC = 0.742; p = 0.022).

CONCLUSIONS

Non-invasive biomarkers can be used to predict each stage of NAFLD in children. The measurements of P1NP, IL-6 or M2BPGi along with the basic chemistry tests would help determine the stage of NAFLD they correspond to at the time of initial diagnosis and predict responsiveness after the treatment.

Bone Density, Geometry, and Mass by Peripheral Quantitative Computed Tomography and Bone Turnover Markers in Children with Diabetes Mellitus Type 1

BACKGROUND

The type 1 diabetes mellitus (T1DM) is a chronic systemic autoimmune-mediated disease characterised by the insulin deficiency and hyperglycaemia. Its deleterious effect on bones concerns not only bone mass, density, and fracture risk but also may involve the linear growth of long bones. Studies on the lower leg in children with T1DM by pQCT have generated conflicting results, and most of the studies published so far focused only on a selected features of the bone. An additional information about growth, modelling, and remodelling processes can be gathered by the bone turnover marker measurement. The objective of the study was to evaluate bone mineral density, mass, and geometry using peripheral quantitative computed tomography as well as bone turnover markers in the patients with type 1 diabetes mellitus. Material and Methods. Bone mineral density, mass, and geometry on the lower leg using peripheral quantitative computed tomography and serum osteocalcin (OC) and carboxyterminal cross-linked telopeptide of type 1 collagen (CTx) were measured in 35 adolescents with T1DM (15 girls) aged 12.3-17.9 yrs. The results were compared to age- and sex-adjusted reference values for healthy controls.

RESULTS

Both sexes reveal lower than zero Z-scores for lower leg 66% total cortical bone cross-sectional area to muscle cross-sectional area ratio (-0.97 ± 1.02, p = 0.002517 and -0.98 ± 1.40, p = 0.007050, respectively) while tibia 4% trabecular bone density Z-score was lowered in boys (-0.67 ± 1.20, p = 0.02259). In boys in Tanner stage 5 bone mass and dimensions were diminished in comparison to Tanner stages 3 and 4, while in girls, such a phenomenon was not observed. Similarly, bone formation and resorption were decreased in boys but not in girls. Consistently, bone turnover markers correlated positively with bone size, dimensions, and strength in boys only.

CONCLUSIONS

T1DM patients revealed a decreased ratio of cortical bone area/muscle area, reflecting disturbed adaptation of the cortical shaft to the muscle force. When analyzing bone mass and dimensions, boys in Tanner stage 5 diverged from "less-mature" individuals, which may suggest that bone development in these individuals was impaired, affecting all three: mass, size, and strength. Noted in boys, suppressed bone metabolism may result in impairment of bone strength because of inadequate repair of microdamage and accumulation of microfractures.

Mechanisms of altered bone remodeling in children with type 1 diabetes

Bone loss associated with type 1 diabetes mellitus (T1DM) begins at the onset of the disease, already in childhood, determining a lower bone mass peak and hence a greater risk of osteoporosis and fractures later in life. The mechanisms underlying diabetic bone fragility are not yet completely understood. Hyperglycemia and insulin deficiency can affect the bone cells functions, as well as the bone marrow fat, thus impairing the bone strength, geometry, and microarchitecture. Several factors, like insulin and growth hormone/insulin-like growth factor 1, can control bone marrow mesenchymal stem cell commitment, and the receptor activator of nuclear factor-κB ligand/osteoprotegerin and Wnt-b catenin pathways can impair bone turnover. Some myokines may have a key role in regulating metabolic control and improving bone mass in T1DM subjects. The aim of this review is to provide an overview of the current knowledge of the mechanisms underlying altered bone remodeling in children affected by T1DM.

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.

JKAMP inhibits the osteogenic capacity of adipose-derived stem cells in diabetic osteoporosis by modulating the Wnt signaling pathway through intragenic DNA methylation

Background

Diabetic osteoporosis (DOP) is a systemic metabolic bone disease caused by diabetes mellitus (DM). Adipose-derived stem cells (ASCs) play an important role in bone regeneration. Our previous study confirmed that ASCs from DOP mice (DOP-ASCs) have a lower osteogenesis potential compared with control ASCs (CON-ASCs). However, the cause of this poor osteogenesis has not been elucidated. Therefore, this study investigated the underlying mechanism of the decline in the osteogenic potential of DOP-ASCs from the perspective of epigenetics and explored methods to enhance their osteogenic capacity.

Methods

The expression level of JNK1-associated membrane protein (JKAMP) and degree of DNA methylation in CON-ASCs and DOP-ASCs were measured by mRNA expression profiling and MeDIP sequencing, respectively. JKAMP small interfering RNA (siRNA) and a Jkamp overexpression plasmid were used to assess the role of JKAMP in osteogenic differentiation of CON-ASCs and DOP-ASCs. Immunofluorescence, qPCR, and western blotting were used to measure changes in expression of Wnt signaling pathway-related genes and osteogenesis-related molecules after osteogenesis induction. Alizarin red and ALP staining was used to confirm the osteogenic potential of stem cells. Bisulfite-specific PCR (BSP) was used to detect JKAMP methylation degree.

Results

Expression of JKAMP and osteogenesis-related molecules (RUNX2 and OPN) in DOP-ASCs was decreased significantly in comparison with CON-ASCs. JKAMP silencing inhibited the Wnt signaling pathway and reduced the osteogenic ability of CON-ASCs. Overexpression of JKAMP in DOP-ASCs rescued the impaired osteogenic capacity caused by DOP. Moreover, JKAMP in DOP-ASCs contained intragenic DNA hypermethylated regions related to the downregulation of JKAMP expression.

Conclusions

Intragenic DNA methylation inhibits the osteogenic ability of DOP-ASCs by suppressing expression of JKAMP and the Wnt signaling pathway. This study shows an epigenetic explanation for the reduced osteogenic ability of DOP-ASCs and provides a potential therapeutic target to prevent and treat osteoporosis.

Role of osteogenic Dickkopf-1 in bone remodeling and bone healing in mice with type I diabetes mellitus

Type 1 diabetes mellitus (T1DM) is associated with low bone mass and a higher risk for fractures. Dickkopf-1 (Dkk1), which inhibits Wnt signaling, osteoblast function, and bone formation, has been found to be increased in the serum of patients with T1DM. Here, we investigated the functional role of Dkk1 in T1DM-induced bone loss in mice. T1DM was induced in 10-week-old male mice with Dkk1-deficiency in late osteoblasts/osteocytes (Dkk1^f/f;Dmp1-Cre, cKO) and littermate control mice by 5 subsequent injections of streptozotocin (40 mg/kg). Age-matched, non-diabetic control groups received citrate buffer instead. At week 12, calvarial defects were created in subgroups of each cohort. After a total of 16 weeks, weight, fat, the femoral bone phenotype and the area of the bone defect were analyzed using µCT and dynamic histomorphometry. During the experiment, diabetic WT and cKO mice did not gain body weight compared to control mice. Further they lost their perigonadal and subcutaneous fat pads. Diabetic mice had highly elevated serum glucose levels and impaired glucose tolerance, regardless of their Dkk1 levels. T1DM led to a 36% decrease in trabecular bone volume in Cre− negative control animals, whereas Dkk1 cKO mice only lost 16%. Of note, Dkk1 cKO mice were completely protected from T1DM-induced cortical bone loss. T1DM suppressed the bone formation rate, the number of osteoblasts at trabecular bone, serum levels of P1NP and bone defect healing in both, Dkk1-deficient and sufficient, mice. This may be explained by increased serum sclerostin levels in both genotypes and the strict dependence on bone formation for bone defect healing. In contrast, the number of osteoclasts and TRACP 5b serum levels only increased in diabetic control mice, but not in Dkk1 cKO mice. In summary, Dkk1 derived from osteogenic cells does not influence the development of T1DM but plays a crucial role in T1DM-induced bone loss in male mice by regulating osteoclast numbers.

Differential responses of bone to angiotensin II and angiotensin(1-7): beneficial effects of ANG(1-7) on bone with exposure to high glucose

Osteoporosis, diabetes, and hypertension are common concurrent chronic disorders. This study aimed to explore the respective effects of angiotensin II (ANG II) and angiotensin(1-7) [ANG(1-7)], active peptides in the renin-angiotensin system, on osteoblasts and osteoclasts under high-glucose level, as well as to investigate the osteo-preservative effects of ANG II type 1 receptor (AT1R) blocker and ANG(1-7) in diabetic spontaneously hypertensive rats (SHR). ANG II and ANG(1-7), respectively, decreased and increased the formation of calcified nodules and alkaline phosphatase activity in MC3T3-E1 cells under high-glucose level, and respectively stimulated and inhibited the number of matured osteoclasts and pit resorptive area in RANKL-induced bone marrow macrophages. Olmesartan and Mas receptor antagonist A779 could abolish those effects. ANG II and ANG(1-7), respectively, downregulated and upregulated the expressions of osteogenesis factors in MC3T3-E1 cells. ANG II promoted the expressions of cathepsin K and MMP9 in RAW 264.7 cells, whereas ANG(1-7) repressed these osteoclastogenesis factors. ANG II rapidly increased the phosphorylation of Akt and p38 in RAW 264.7 cells, whereas ANG(1-7) markedly reduced the phosphorylation of p38 and ERK under high-glucose condition. After treatments of diabetic SHR with valsartan and ANG(1-7), a significant increase in trabecular bone area, bone mineral density, and mechanical strength was only found in the ANG(1-7)-treated group. Treatment with ANG(1-7) significantly suppressed the increase in renin expression and ANG II content in the bone of SHR. Taken together, ANG II/AT1R and ANG(1-7)/Mas distinctly regulated the differentiation and functions of osteoblasts and osteoclasts upon exposure to high-glucose condition. ANG(1-7) could protect SHR from diabetes-induced osteoporosis.

Bone regeneration in a mouse model of type 1 diabetes: Influence of sex, vitamin D3, and insulin

AIM

This study set forth a question: are there any differences in bone responses to insulin and/or vitamin D3 treatment in female and male type 1 diabetic (T1D) mice?

MAIN METHODS

To address this issue, a non-critical sized femur defect was created in streptozotocin (STZ)-T1D mice. Control non-diabetic and T1D female and male mice received: saline; vitamin D3; insulin; or vitamin D3 plus insulin, for 21 days.

KEY FINDINGS

Female and male T1D mice showed impaired bone healing, as indicated by histological and micro-computed tomography (micro-CT) analysis. Vitamin D3 or insulin improved the bone regeneration in T1D mice, irrespective of sex. Vitamin D3 plus insulin did not exhibit any additional effects. There were no differences regarding the numbers of TRAP-stained osteoclasts in either evaluated groups. The osteoblast-related gene osterix was upregulated in vitamin D3-treated male T1D mice, as revealed by RT-qPCR. Female T1D mice treated with vitamin D3, insulin, or vitamin D3 plus insulin presented an increased expression of insulin growth factor-1 (IGF-1) mRNA. Conversely, IGF-1 mRNA levels were reduced by the same treatments in male TD1 mice.

SIGNIFICANCE

Altogether, the results suggested that T1D similarly delayed the osseous healing in female and male mice, with beneficial effects for either vitamin D3 or insulin in T1D mice of both sexes. However, data indicated marked sex differences regarding the expression of genes implicated in bone formation, in T1D mice treated with vitamin D3 and/or insulin.

Systemic TNFα correlates with residual β-cell function in children and adolescents newly diagnosed with type 1 diabetes

BACKGROUND

Type 1 diabetes (T1D) is caused by immune-mediated destruction of the β-cells. After initiation of insulin therapy many patients experience a period of improved residual β-cell function leading to partial disease remission. Cytokines are important immune-modulatory molecules and contribute to β-cell damage in T1D. The patterns of systemic circulating cytokines during T1D remission are not clear but may constitute biomarkers of disease status and progression. In this study, we investigated if the plasma levels of various pro- and anti-inflammatory cytokines around time of diagnosis were predictors of remission and residual β-cell function in children with T1D followed for one year after disease onset.

METHODS

In a cohort of 63 newly diagnosed children (33% females) with T1D with a mean age of 11.3 years (3.3-17.7), ten cytokines were measured of which eight were detectable in plasma samples by Mesoscale Discovery multiplex technology at study start and after 6 and 12 months. Linear regression models were used to evaluate association of cytokines with stimulated C-peptide.

RESULTS

Systemic levels of tumor necrosis factor (TNF)-α, interleukin (IL)-2 and IL-6 inversely correlated with stimulated C-peptide levels over the entire study (P < 0.05). The concentrations of TNFα and IL-10 at study start predicted stimulated C-peptide level at 6 months (P = 0.011 and P = 0.043, respectively, adjusted for sex, age, HbA1c and stage of puberty).

CONCLUSIONS

In recent-onset T1D, systemic cytokine levels, and in particular that of TNFα, correlate with residual β-cell function and may serve as prognostic biomarkers of disease remission and progression to optimize treatment strategies.

TRIAL REGISTRATION

The study was performed according to the criteria of the Helsinki II Declaration and was approved by the Danish Capital Region Ethics Committee on Biomedical Research Ethics (journal number H-3-2014-052). The parents of all participants gave written consent.

Acute Hyperinsulinemia Alters Bone Turnover in Women and Men With Type 1 Diabetes

Type 1 diabetes (T1D) increases fracture risk across the lifespan. The low bone turnover associated with T1D is thought to be related to glycemic control, but it is unclear whether peripheral hyperinsulinemia due to dependence on exogenous insulin has an independent effect on suppressing bone turnover. The purpose of this study was to test the bone turnover marker (BTM) response to acute hyperinsulinemia. Fifty‐eight adults aged 18 to 65 years with T1D over 2 years were enrolled at seven T1D Exchange Clinic Network sites. Participants had T1D diagnosis between age 6 months to 45 years. Participants were stratified based on their residual endogenous insulin secretion measured as peak C‐peptide response to a mixed meal tolerance test. BTMs (CTX, P1NP, sclerostin [SCL], osteonectin [ON], alkaline phosphatase [ALP], osteocalcin [OCN], osteoprotegerin [OPG], osteopontin [OPN], and IGF‐1) were assessed before and at the end of a 2‐hour hyperinsulinemic‐euglycemic clamp (HEC). Baseline ON (r = −0.30, p = .022) and OCN (r = −0.41, p = .002) were negatively correlated with age at T1D diagnosis, but baseline BTMs were not associated with HbA1c. During the HEC, P1NP decreased significantly (−14.5 ± 44.3%; p = .020) from baseline. OCN, ON, and IGF‐1 all significantly increased (16.0 ± 13.1%, 29.7 ± 31.7%, 34.1 ± 71.2%, respectively; all p < .001) during the clamp. The increase in SCL was not significant (7.3 ± 32.9%, p = .098), but the decrease in CTX (−12.4 ± 48.9, p = .058) neared significance. ALP and OPG were not changed from baseline (p = .23 and p = .77, respectively). Baseline ON and SCL were higher in men, but OPG was higher in women (all p ≤ .029). SCL was the only BTM that changed differently in women than men. There were no differences in baseline BTMs or change in BTMs between C‐peptide groups. Exogenous hyperinsulinemia acutely alters bone turnover, suggesting a need to determine whether strategies to promote healthy remodeling may protect bone quality in T1D. © 2020 American Society for Bone and Mineral Research © 2020 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Decreased markers of bone turnover in children and adolescents with type 1 diabetes

BACKGROUND AND AIM

Adults with type 1 diabetes (T1D) have increased risk of bone fractures and decreased bone mineral density (BMD). Alterations in bone turnover have been suggested as the link between T1D and the impaired bone health. Furthermore, bone turnover has been suggested to have beneficial effects on glucose metabolism. This study aimed at describing bone turnover markers (BTM), and the relationship with glycemic control, in children and adolescents with T1D.

METHODS

A total of 173 (47% girls) children and adolescents aged 7.7 to 17.5 years with T1D for more than 1 year were included. Participants were evaluated by BMD together with measurements of selected BTM; two formation markers: osteocalcin (OCN) and procollagen type-1 amino-terminal propeptide (P1NP) and one resorption marker, C-terminal cross-linked telopeptide of type-1 collagen (CTX). BTM were converted into Z-scores utilizing new national references.

RESULTS

Mean OCN Z-score (-0.68 ± 1.31), P1NP Z-score (-0.33 ± 1.03) and CTX Z-score (-0.43 ± 1.10) were all significantly lower than the reference population (P < .001). No associations were seen between BTM and T1D duration. BMD Z-score was comparable to the reference population and associated with none of individual BTMs. CTX Z-score was negatively associated with HbA1c (P = .007) independent of both exogenous and residual endogenous insulin.

CONCLUSIONS

Markers of bone formation and resorption were decreased in children and adolescents with T1D. CTX Z-score associated negatively with HbA1c adjusted for insulin treatment and endogenous insulin production indicating a potential association between CTX and insulin sensitivity. The long-term consequences of decreased BTM on BMD need further attention.

Elevated HbA1c Is Associated with Altered Cortical and Trabecular Microarchitecture in Girls with Type 1 Diabetes

CONTEXT

Skeletal fragility is a significant complication of type 1 diabetes (T1D), with an increased risk of fracture observed starting in childhood. Altered bone accrual and microarchitectural development during the critical peripubertal years may contribute to this fragility.

OBJECTIVE

To evaluate differences in skeletal microarchitecture between girls with T1D and controls and to assess factors associated with these differences.

DESIGN

Cross-sectional comparison.

PARTICIPANTS

Girls ages 10-16 years, 62 with T1D and 61 controls.

RESULTS

Areal bone mineral density (BMD) measured by dual-energy x-ray absorptiometry did not differ between girls with and without T1D. At the distal tibia, trabecular BMD was 7.3 ± 2.9% lower in T1D (P = 0.013), with fewer plate-like and axially-aligned trabeculae. Cortical porosity was 21.5 ± 10.5% higher, while the estimated failure load was 4.7 ± 2.2% lower in T1D (P = 0.043 and P = 0.037, respectively). At the distal radius, BMD and microarchitecture showed similar differences between the groups but did not reach statistical significance. After stratifying by HbA1c, only those girls with T1D and HbA1c > 8.5% differed significantly from controls. P1NP, a marker of bone formation, was lower in T1D while CTX and TRAcP5b, markers of bone resorption and osteoclast number, respectively, did not differ. The insulin-like growth factor 1 (IGF-1) Z-score was lower in T1D, and after adjustment for the IGF-1 Z-score, associations between T1D status and trabecular microarchitecture were largely attenuated.

CONCLUSIONS

Skeletal microarchitecture is altered in T1D early in the course of disease and among those with higher average glycemia. Suppressed bone formation and lower circulating IGF-1 likely contribute to this phenotype.

Bone turnover markers during the remission phase in children and adolescents with type 1 diabetes

BACKGROUND AND AIM

In rodents, osteocalcin (OCN) stimulates insulin production and insulin sensitivity, both important factors during partial remission in humans with type 1 diabetes (T1D). However, decreased OCN has been reported in both adult and pediatric T1D. This study aims at investigating bone turnover and partial remission in children and adolescents with recent onset T1D.

SUBJECTS AND METHODS

Ninety-nine individuals (33% girls) were recruited within 3 months of T1D onset and examined three times, 6 months apart. Outcome variables were bone formation markers OCN and procollagen type 1 amino-terminal propeptide (P1NP) and the bone resorption marker C-terminal crosslinked telopeptide of type 1 collagen (CTX). Dependent variables included IDAA1c (surrogate marker of partial remission), total body bone mineral density (BMD) and stimulated C-peptide as representative of endogenous insulin production.

RESULTS

OCN- and P1NP Z-scores were significantly decreased throughout the study, whereas CTX Z-scores were increased. None of the bone turnover markers changed significantly between visits. Total body BMD Z-score did not change during the study but was significantly higher than the reference population at visit 2 (P = .035). There were no differences in the bone turnover markers for those in partial remission as defined by either C-peptide or IDAA1c at any visit. The individual change in CTX Z-score was negatively associated with the increase of IDAA1c (P = .030) independent of C-peptide decline (P = .034).

CONCLUSION

Bone turnover markers indicate increased bone resorption and decreased bone formation during the first year of T1D. The negative association between bone resorption and IDAA1c might represent compensatory mechanisms affecting insulin sensitivity.

Association Study between BGLAP Gene HindIII Polymorphism and Type 2 Diabetes Mellitus Development in Ukrainian Population

Type 2 diabetes mellitus (T2DM) belongs to the diseases with hereditary predisposition, so both environmental and genetic factors contribute to its development. Recent studies have demonstrated that the skeleton realizes systemic regulation of energy metabolism through the secretion of osteocalcin (OCN). Thus, the association analysis between HindIII single nucleotide polymorphism of OCN gene (BGLAP) promoter region and T2DM development in Ukrainian population was carried out. 153 individuals diagnosed with T2DM and 311 control individuals were enrolled in the study. The genotyping was performed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. The lack of association between BGLAP HindIII single nucleotide polymorphism (SNP) and T2DM development among Ukrainians was found. Further studies with extended groups of comparison are needed to confirm the obtained results.

Impact of Diabetes Mellitus on Bone Health

Long-term exposure to a diabetic environment leads to changes in bone metabolism and impaired bone micro-architecture through a variety of mechanisms on molecular and structural levels. These changes predispose the bone to an increased fracture risk and impaired osseus healing. In a clinical practice, adequate control of diabetes mellitus is essential for preventing detrimental effects on bone health. Alternative fracture risk assessment tools may be needed to accurately determine fracture risk in patients living with diabetes mellitus. Currently, there is no conclusive model explaining the mechanism of action of diabetes mellitus on bone health, particularly in view of progenitor cells. In this review, the best available literature on the impact of diabetes mellitus on bone health in vitro and in vivo is summarised with an emphasis on future translational research opportunities in this field.

Type 1 Diabetes and Bone Fragility: Links and Risks

Type 1 diabetes (T1D) is associated with an increased fracture risk, which is present at young and old age. Reductions in bone mineral density do not explain the increased fracture risk. Novel scanning modalities suggest that structural deficits may contribute to the increased fracture risk. Furthermore, T1D may due to insulinopenia be a state of low bone turnover. However, diabetes complications and comorbidities may influence fracture risk. Patients with T1D are fearful of falls. The diabetes related complications, hypoglycemic events, and antihypertensive treatment may all lead to falls. Thus, the increased fracture risk in T1D seems to be multifactorial, and earlier intervention with antiosteoporotic medication and focus on fall prevention is needed. This systematic review addresses the epidemiology of fractures and osteoporosis in patients with T1D and the factors that influence fracture risk.