Bone densitometry and biochemical bone remodeling markers in type 1 diabetes mellitus

Microvascular disease and early diabetes onset are associated with deficits in femoral neck bone density and structure among older adults with longstanding type 1 diabetes

Adults with type 1 diabetes (T1D) have increased hip fracture risk, yet no studies have assessed volumetric bone density or structure at the hip in older adults with T1D. Here, we used previously collected 3D CT scans of the proximal femur from older adults with longstanding T1D and non-diabetic controls to identify bone deficits that may contribute to hip fracture in T1D. In this retrospective cohort study, we identified 101 adults with T1D and 181 age-, sex-, and race-matched non-diabetic controls (CON) who received abdominal or pelvis CT exams from 2010 to 2020. Among adults with T1D, 33 (33%) had mild-to-moderate nephropathy, 61 (60%) had neuropathy, and 71 (70%) had retinopathy. Within the whole cohort, adults with T1D tended to have lower FN density, though differences did not reach statistical significance. The subset of the T1D group who were diagnosed before age 15 had lower total BMC (-14%, TtBMC), cortical BMC (-19.5%, CtBMC), and smaller Ct cross-sectional area (-12.6, CtCSA) than their matched controls (p<.05 for all). Individuals with T1D who were diagnosed at a later age did not differ from controls in any bone outcome (p>.21). Furthermore, adults with T1D and nephropathy had lower FN aBMD (-10.6%), TtBMC (-17%), CtBMC (-24%), and smaller CtCSA (-15.4%) compared to matched controls (p<.05 for all). Adults with T1D and neuropathy had cortical bone deficits (8.4%-12%, p<.04). In summary, among older adults with T1D, those who were diagnosed before the age of 15 yr, as well as those with nephropathy and neuropathy had unfavorable bone outcomes at the FN, which may contribute to the high risk of hip fractures among patients with T1D. These novel observations highlight the longstanding detrimental impact of T1D when present during bone accrual and skeletal fragility as an additional complication of microvascular disease in individuals with T1D.

Diabetes and osteoporosis: a two-sample mendelian randomization study

BACKGROUND

The effects on bone mineral density (BMD)/fracture between type 1 (T1D) and type 2 (T2D) diabetes are unknown. Therefore, we aimed to investigate the causal relationship between the two types of diabetes and BMD/fracture using a Mendelian randomization (MR) design.

METHODS

A two-sample MR study was conducted to examine the causal relationship between diabetes and BMD/fracture, with three phenotypes (T1D, T2D, and glycosylated hemoglobin [HbA1c]) of diabetes as exposures and five phenotypes (femoral neck BMD [FN-BMD], lumbar spine BMD [LS-BMD], heel-BMD, total body BMD [TB-BMD], and fracture) as outcomes, combining MR-Egger, weighted median, simple mode, and inverse variance weighted (IVW) sensitivity assessments. Additionally, horizontal pleiotropy was evaluated and corrected using the residual sum and outlier approaches.

RESULTS

The IVW method showed that genetically predicted T1D was negatively associated with TB-BMD (β = -0.018, 95% CI: -0.030, -0.006), while T2D was positively associated with FN-BMD (β = 0.033, 95% CI: 0.003, 0.062), heel-BMD (β = 0.018, 95% CI: 0.006, 0.031), and TB-BMD (β = 0.050, 95% CI: 0.022, 0.079). Further, HbA1c was not associated with the five outcomes (β ranged from - 0.012 to 0.075).

CONCLUSIONS

Our results showed that T1D and T2D have different effects on BMD at the genetic level. BMD decreased in patients with T1D and increased in those with T2D. These findings highlight the complex interplay between diabetes and bone health, suggesting potential age-specific effects and genetic influences. To better understand the mechanisms of bone metabolism in patients with diabetes, further longitudinal studies are required to explain BMD changes in different types of diabetes.

Role of advanced glycation endproducts in bone fragility in type 1 diabetes

The excess fracture risk observed in adults with type 1 diabetes (T1D) is inexplicable in the presence of only modest reductions in areal bone mineral density (BMD). Accumulation of advanced glycation endproducts (AGEs) in bone has been invoked as one explanation for the increased bone fragility in diabetes. The evidence linking AGEs and fractures in individuals with T1D is sparse, although the association has been observed in individuals with type 2 diabetes. Recent data show that in T1D, AGEs as measured by skin intrinsic fluorescence, are a risk factor for lower BMD. Further research in T1D is needed to ascertain whether there is a causal relationship between fractures and AGEs. If confirmed, this would pave the way for finding interventions that can slow AGE accumulation and thus reduce fractures in T1D.

Vascular deficits contributing to skeletal fragility in type 1 diabetes

Over 1 million Americans are currently living with T1D and improvements in diabetes management have increased the number of adults with T1D living into later decades of life. This growing population of older adults with diabetes is more susceptible to aging comorbidities, including both vascular disease and osteoporosis. Indeed, adults with T1D have a 2- to 3- fold higher risk of any fracture and up to 7-fold higher risk of hip fracture compared to those without diabetes. Recently, diabetes-related vascular deficits have emerged as potential risks factors for impaired bone blood flow and poor bone health and it has been hypothesized that there is a direct pathophysiologic link between vascular disease and skeletal outcomes in T1D. Indeed, microvascular disease (MVD), one of the most serious consequences of diabetes, has been linked to worse bone microarchitecture in older adults with T1D compared to their counterparts without MVD. The association between the presence of microvascular complications and compromised bone microarchitecture indicates the potential direct deleterious effect of vascular compromise, leading to abnormal skeletal blood flow, altered bone remodeling, and deficits in bone structure. In addition, vascular diabetic complications are characterized by increased vascular calcification, decreased arterial distensibility, and vascular remodeling with increased arterial stiffness and thickness of the vessel walls. These extensive alterations in vascular structure lead to impaired myogenic control and reduced nitric-oxide mediated vasodilation, compromising regulation of blood flow across almost all vascular beds and significantly restricting skeletal muscle blood flow seen in those with T1D. Vascular deficits in T1D may very well extend to bone, compromising skeletal blood flow control, and resulting in reduced blood flow to bone, thus negatively impacting bone health. Indeed, several animal and ex vivo human studies report that diabetes induces microvascular damage within bone are strongly correlated with diabetes disease severity and duration. In this review article, we will discuss the contribution of diabetes-induced vascular deficits to bone density, bone microarchitecture, and bone blood flow regulation, and review the potential contribution of vascular disease to skeletal fragility in T1D.

Biochemical Markers of Bone Turnover in Older Adults With Type 1 Diabetes

CONTEXT

Type 1 diabetes (T1D) is characterized by high fracture risk, yet little is known regarding diabetes-related mechanisms or risk factors.

OBJECTIVE

Determine whether glycemic control, advanced glycation end products (AGEs), and microvascular complications are associated with bone turnover markers among older T1D adults.

DESIGN

Cross-sectional.

SETTING

Epidemiology of Diabetes Interventions and Complications study (6 of 27 clinical centers).

PARTICIPANTS

232 T1D participants followed for >30 years.

EXPOSURES

Glycemic control ascertained as concurrent and cumulative hemoglobin A1c (HbA1c); kidney function, by estimated glomerular filtration rates (eGFR); and AGEs, by skin intrinsic fluorescence.

MAIN OUTCOME MEASURES

Serum procollagen 1 intact N-terminal propeptide (PINP), bone-specific alkaline phosphatase (bone ALP), serum C-telopeptide (sCTX), tartrate-resistant acid phosphatase 5b (TRACP5b), and sclerostin.

RESULTS

Mean age was 59.6 ± 6.8 years, and 48% were female. In models with HbA1c, eGFR, and AGEs, adjusted for age and sex, higher concurrent HbA1c was associated with lower PINP [β -3.4 pg/mL (95% CI -6.1, -0.7), P = 0.015 for each 1% higher HbA1c]. Lower eGFR was associated with higher PINP [6.9 pg/mL (95% CI 3.8, 10.0), P < 0.0001 for each -20 mL/min/1.73 m2 eGFR], bone ALP [1.0 U/L (95% CI 0.2, 1.9), P = 0.011], sCTX [53.6 pg/mL (95% CI 32.6, 74.6), P < 0.0001], and TRACP5b [0.3 U/L (95% CI 0.1, 0.4), P = 0.002]. However, AGEs were not associated with any bone turnover markers in adjusted models. HbA1c, eGFR, and AGEs were not associated with sclerostin levels.

CONCLUSIONS

Among older adults with T1D, poor glycemic control is a risk factor for reduced bone formation, while reduced kidney function is a risk factor for increased bone resorption and formation.

Association of Insulin Glargine Treatment with Bone Mineral Density in Patients with Type 2 Diabetes Mellitus

PURPOSE

To assess the association of type 2 diabetes mellitus (T2DM) and insulin glargine treatment with bone mineral density (BMD) in Chinese people.

METHODS

This retrospective study included 50 subjects with T2DM: 25 received oral glucose-lowering medication (ORL group), and 25 received oral glucose-lowering medication in combination with insulin glargine injection (CGI group). Thirty non-diabetic control subjects were also included. BMD was measured at lumbar vertebrae 1-4 (L1-L4), spine bone mineral density (sBMD) results summary (L2-L4), femoral neck and trochanter by dual-energy x-ray absorptiometry.

RESULTS

Compared with non-diabetic controls, people with T2DM had significantly lower mean BMD at L2 (1.073±0.120 vs 0.984±0.158), L3 (1.094±0.129 vs 0.991±0.163) and L4 (1.089±0.130 vs 0.982±0.165) (all P<0.05), significantly lower levels of serum calcium (2.02±0.22 vs 2.27±0.17 mmol/L, P<0.05), PTH (24.19±9.71 vs 31.52±8.96 pg/mL, P<0.05), and higher serum phosphate levels (1.43±0.37 vs 1.20±0.15 mmol/L, P<0.05). The CGI group had higher L2, L3 and L4 BMD and sBMD (L2-L4) (P<0.05), higher serum calcium levels (2.19±0.11 vs 1.98±0.20 mmol/L, P<0.05) and lower serum phosphate levels (1.28±0.20 vs 1.58±0.43 mmol/L, P<0.05) versus the ORL group. BMD and serum calcium levels were associated with the application of insulin glargine.

CONCLUSION

These results suggest that insulin glargine may affect bone metabolism in patients diagnosed with T2DM. The study has implications for the selection of hypoglycemic agents for diabetic patients at risk of osteoporosis.

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

Type 1 diabetes (T1D) is associated with impaired bone health and both osteocalcin (OCN) and procollagen type 1 amino terminal propetide (P1NP) (markers of bone formation) and C-terminal cross-linked telopeptide (CTX) (marker of bone resorption) are decreased in adult patients with T1D. We review the existing literature characterizing these bone turnover markers in children and adolescents with T1D and by meta-analysis examine whether alterations in OCN, P1NP, and CTX are evident and if potential changes correlate to the metabolic control (hemoglobin A1c, HbA1c). Systematic searches at MEDLINE and EMBASE were conducted in January 2018 identifying all studies describing OCN, P1NP, or CTX in children and adolescents with T1D. A total of 26 studies were included, representing data from more than 1000 patients with T1D. Pooled analyses of standard mean difference and summary effects analysis were performed when sufficient data were available. Pooled analysis revealed mean OCN to be significantly lower in children and adolescents with T1D compared to healthy controls (standard mean difference: -1.87, 95% confidence interval, CI: -2.83; -0.91) whereas both P1NP and CTX did not differ from the controls. Only data on OCN was sufficient to make pooled correlation analysis revealing a negative correlation between OCN and HbA1c (-0.31 95% CI: -0.45; -0.16). In conclusion, OCN is decreased in children and adolescents with T1D, whether CTX and P1NP are affected as well is unclear, due to very limited data available. New and large studies including OCN, P1NP, and CTX (preferably as z-scores adjusting for age variability) is needed to further elucidate the status of bone turnover in children and adolescents with T1D.

Relationship between Body Mass Index and T-Scores of Bone Mineral Density in the Hip and Spine Regions among Older Adults with Diabetes: A Retrospective Review

Diabetes mellitus (DM) cases are increasing worldwide, especially in Saudi Arabia. Previous studies suggested a positive relationship between body mass index (BMI) and bone mineral density (BMD) levels. Generally, patients with low BMI (<18.5 kg/m2) have reduced BMD levels and, thus, low T-scores; hence, they are categorized as osteopenic or osteoporotic. In this study, we aimed to determine whether a relationship between BMI and BMD T-scores in the hip and spine regions of patients with diabetes exists. This retrospective record review investigated older adult patients with diabetes in King Abdulaziz University Hospital (n=198; age 50-90 years) who underwent BMD scan between January 1, 2016, and June 25, 2018, regardless of their sex but limited to type 2 DM. The height and weight of all subjects were recorded, and BMI was calculated and categorized. We used SPSS version 21 for data analysis; measures of central tendencies, Pearson's correlations, chi-square tests, and independent t-tests were employed. We found positive relationships between BMI and BMD T-scores in the hip and spine regions (right femoral neck: R=+0.214, P ≤ 0.002; total right hip: R=+0.912, P ≤ 0.001; left femoral neck: R=+0.939, P ≤ 0.001; total left hip: R=+0.885, P ≤ 0.001; and total lumbar region: R=+0.607, P ≤ 0.001). Low BMI (<18.5 kg/m2) could be a risk factor for osteoporosis, whereas normal/high BMI could be protective against osteoporosis among adults with diabetes.

A 10-Year Prospective Study of Bone Mineral Density and Bone Turnover in Males and Females With Type 1 Diabetes

CONTEXT

In a previous community-based, cross-sectional study, males with type 1 diabetes (T1D) had lower bone mineral density (BMD) than did matched people without diabetes but females with T1D had normal BMD.

OBJECTIVE

To determine whether BMD in the males continued to decline, the neutral effect of T1D on BMD in females persisted, and whether temporal BMD changes reflected changes in bone turnover markers.

DESIGN

Longitudinal observational study.

SETTING

Urban community.

PATIENTS

Forty-eight of the original 102 original cross-sectional study participants (20 males, 28 females) of mean age 42.0 years and median diabetes duration 14.6 years at baseline who were restudied a mean of 10.3 years later.

MAIN OUTCOME MEASURES

BMD at total hip, femoral neck, lumbar spine (L1 to L4), and distal forearm. Biochemical bone turnover markers.

RESULTS

After adjustment for age, body mass index (BMI), and renal function, there was no temporal change in BMD at the hip or forearm in the males (P ≥ 0.12), but lumbar spine BMD increased (P = 0.009). Females exhibited no statistically significant change in BMD in similar multivariable models that also included postmenopausal status, except a mild increase at the forearm (P = 0.046). Age- and sex-related changes in bone turnover markers paralleled those in general population studies.

CONCLUSIONS

There is a reduction in BMD in males with T1D that occurs early in the course of the disease but then stabilizes. BMD in females with T1D remains similar to that expected for age, BMI, and postmenopausal status.

Assessment of bone quality in patients with diabetes mellitus

Substantial evidence exists that diabetes mellitus is associated with an increased risk of osteoporotic fractures. Low bone strength as well as bone extrinsic factors are probably contributing to the increased bone fragility in diabetes. Bone density and quality are important determinants of bone strength. Although bone mineral density (BMD) and the fracture risk assessment tool (FRAX) are very useful clinical tools in assessing bone strength, they may underestimate the fracture risk in diabetes mellitus. Through advances in new technologies such as trabecular bone score (TBS) and peripheral quantitative computed tomography (pQCT), we can better assess the bone quality and fracture risk of patients with diabetes mellitus. Invasive assessments such as microindentation and histomorphometry have been great complement to the existing bone analysis techniques. Bone turnover markers have been found to be altered in diabetes mellitus patients and may be associated with fractures. This review will give a brief summary of the current development and clinical uses of these assessments.

Osteocalcin Serum Levels in Gestational Diabetes Mellitus and Their Intrinsic and Extrinsic Determinants: Systematic Review and Meta-Analysis

BACKGROUND

Undercarboxylated osteocalcin (ucOC) increases insulin release and insulin resistance in mice. In humans, evidence is scarce but a correlation of ucOC and total osteocalcin (tOC) with glycemic status markers has been demonstrated. The relationship of ucOC and tOC with gestational diabetes mellitus (GDM) has been even less characterized.

OBJECTIVE

To assess the mean difference of tOC and ucOC serum concentrations among nondiabetic pregnant women and women diagnosed as GDM in the second trimester of pregnancy and to determine the possible intrinsic and extrinsic contributors to this difference.

METHODS

A systematic search was performed to identify relevant studies published in English and Spanish using PubMed, SCOPUS, ISI Web of Knowledge, and PROSPERO database for meta-analysis. Observational studies measuring mean serum levels of osteocalcin among GDM, with at least 10 subjects analyzed in each group were selected. Mean difference (MD) by random effects model was used. Heterogeneity between studies was assessed using Cochran's Q, H, and I ² statistics.

RESULTS

From 38 selected studies, 5 were retained for analysis for a total of 1119 pregnant women. Serum concentrations of tOC were not significantly different among women with GDM and nondiabetic pregnant controls (MD: 1.56; 95% CI: -0.70 to 3.82; p = 0.175). Meanwhile, ucOC serum levels were significantly higher among women with GDM (MD: 1.17; 95% CI: 0.24 to 2.11; p = 0.013). The only factor influencing tOC was the UV index, showing a reduction in mean difference between GDM and controls when exposed to higher concentrations of UV rays.

CONCLUSIONS

This meta-analysis provides evidence to support the use of ucOC as a potential marker for GDM rather than tOC, yielding very little variability among studies and no difference among methods or brands used for its analysis.

Bone disease in diabetes: another manifestation of microvascular disease?

Type 1 and type 2 diabetes are generally accepted to be associated with increased bone fracture risk. However, the pathophysiological mechanisms of diabetic bone disease are poorly understood, and whether the associated increased skeletal fragility is a comorbidity or a complication of diabetes remains under debate. Although there is some indication of a direct deleterious effect of microangiopathy on bone, the evidence is open to question, and whether diabetic osteopathy can be classified as a chronic, microvascular complication of diabetes remains uncertain. Here, we review the current knowledge of potential contributory factors to diabetic bone disease, particularly the association between diabetic microangiopathy and bone mineral density, bone structure, and bone turnover. Additionally, we discuss and propose a pathophysiological model of the effects of diabetic microvascular disease on bone, and examine the progression of bone disease alongside the evolution of diabetes.

MECHANISMS IN ENDOCRINOLOGY: Diabetes mellitus, a state of low bone turnover - a systematic review and meta-analysis

OBJECTIVE

To investigate the differences in bone turnover between diabetic patients and controls.

DESIGN

A systematic review and meta-analysis.

METHODS

A literature search was conducted using the databases Medline at PubMed and EMBASE. The free text search terms 'diabetes mellitus' and 'bone turnover', 'sclerostin', 'RANKL', 'osteoprotegerin', 'tartrate-resistant acid' and 'TRAP' were used. Studies were eligible if they investigated bone turnover markers in patients with diabetes compared with controls. Data were extracted by two reviewers.

RESULTS

A total of 2881 papers were identified of which 66 studies were included. Serum levels of the bone resorption marker C-terminal cross-linked telopeptide (-0.10 ng/mL (-0.12, -0.08)) and the bone formation markers osteocalcin (-2.51 ng/mL (-3.01, -2.01)) and procollagen type 1 amino terminal propeptide (-10.80 ng/mL (-12.83, -8.77)) were all lower in patients with diabetes compared with controls. Furthermore, s-tartrate-resistant acid phosphatase was decreased in patients with type 2 diabetes (-0.31 U/L (-0.56, -0.05)) compared with controls. S-sclerostin was significantly higher in patients with type 2 diabetes (14.92 pmol/L (3.12, 26.72)) and patients with type 1 diabetes (3.24 pmol/L (1.52, 4.96)) compared with controls. Also, s-osteoprotegerin was increased among patients with diabetes compared with controls (2.67 pmol/L (0.21, 5.14)).

CONCLUSIONS

Markers of both bone formation and bone resorption are decreased in patients with diabetes. This suggests that diabetes mellitus is a state of low bone turnover, which in turn may lead to more fragile bone. Altered levels of sclerostin and osteoprotegerin may be responsible for this.

Bone Geometry, Volumetric Density, Microarchitecture, and Estimated Bone Strength Assessed by HR-pQCT in Adult Patients With Type 1 Diabetes Mellitus

The primary goal of this cross-sectional in vivo study was to assess peripheral bone microarchitecture, bone strength, and bone remodeling in adult type 1 diabetes (T1D) patients with and without diabetic microvascular disease (MVD+ and MVD-, respectively) and to compare them with age-, gender-, and height-matched healthy control subjects (CoMVD+ and CoMVD-, respectively). The secondary goal was to assess differences in MVD- and MVD+ patients. Fifty-five patients with T1DM (MVD+ group: n = 29) were recruited from the Funen Diabetes Database. Dual-energy X-ray absorptiometry (DXA), high-resolution peripheral quantitative computed tomography (HR-pQCT) of the ultradistal radius and tibia, and biochemical markers of bone turnover were performed in all participants. There were no significant differences in HR-pQCT parameters between MVD- and CoMVD- subjects. In contrast, MVD+ patients had larger total and trabecular bone areas (p = 0.04 and p = 0.02, respectively), lower total, trabecular, and cortical volumetric bone mineral density (vBMD) (p < 0.01, p < 0.04, and p < 0.02, respectively), and thinner cortex (p = 0.03) at the radius, and lower total and trabecular vBMD (p = 0.01 and p = 0.02, respectively) at the tibia in comparison to CoMVD+. MVD+ patients also exhibited lower total and trabecular vBMD (radius p = 0.01, tibia p < 0.01), trabecular thickness (radius p = 0.01), estimated bone strength, and greater trabecular separation (radius p = 0.01, tibia p < 0.01) and network inhomogeneity (radius p = 0.01, tibia p < 0.01) in comparison to MVD- patients. These differences remained significant after adjustment for age, body mass index, gender, disease duration, and glycemic control (average glycated hemoglobin over the previous 3 years). Although biochemical markers of bone turnover were significantly lower in MVD+ and MVD- groups in comparison to controls, they were similar between the MVD+ and MVD- groups. The results of our study suggest that the presence of MVD was associated with deficits in cortical and trabecular bone vBMD and microarchitecture that could partly explain the excess skeletal fragility observed in these patients.

Association between bone mineral density and type 1 diabetes mellitus: a meta-analysis of cross-sectional studies

A few studies have investigated the relationship between type 1 diabetes mellitus (T1DM) and bone mineral density (BMD) values. This meta-analysis was performed to explore differences between T1DM and healthy individuals in BMD values measured at five bone sites.We searched the database of PubMed for cross-sectional studies about the association of T1DM and BMD, and a meta-analysis was conducted.The results suggested significant association between T1DM and decreased BMD values of total body. The pooled mean differences (MDs) were -0.06 [95% confidence interval (CI): -0.11, -0.01] for all people. As for the association between T1DM and spine BMD values, the pooled MDs were -0.04 (95% CI: -0.07, -0.01) for males and -0.03 (95% CI: -0.06, 0.00) for females <20 years old. As for femur BMD values, the pooled MDs were -0.06 (95% CI: -0.13, 0.00) for all people, -0.03 (95% CI: -0.06, -0.01) for females and -0.04(95% CI: -0.05, -0.02) for males. As for hip BMD values, the pooled MDs were -0.06 (95% CI: -0.08, -0.04) for females. As for forearm BMD values, the pooled MDs were -0.01 (95% CI: -0.02, 0.00) for females.The results of this meta-analysis suggest the overall association between T1DM and reduced BMD values. Notably, the influence of T1DM on BMD seems to depend on gender or patient's age. Reduced BMD values may occur early after T1DM diagnosis. Future clinical and basic research studies are needed to further understand the mechanisms of decreased BMD values in T1DM patients.

Type 1 diabetes and osteoporosis: A review of literature

With better care and intensive insulin therapy, microvascular complications have reduced and longevity has increased in patients with type 1 diabetes (T1DM). Therefore, there is a need to change the focus from microvascular complications to cardiovascular disease and osteoporosis. Though number of studies from other parts of the world show that patients with T1DM are at increased risk of osteoporosis and fractures, there is a paucity of data from India. A number of factors and mechanisms affecting bone health in patients with T1DM have been proposed. The main defect in genesis of osteoporosis is osteoblastic function, rather than osteoclastic overfunction. Assessment of bone mineral density by dual X-ray absorptiometry and other risk factors for osteoporosis, as a part of diagnostic procedure can help to design tailored treatment plans. A physically active healthy lifestyle, prevention of diabetic complications and adequate calcium and vitamin D supplementation are the mainstay for prevention of osteoporosis. Treatment of osteoporosis is not evidence based but it is proposed to be similar to osteoporosis associated with other conditions. Bisphosphonates are the mainstay for treatment of osteoporosis in patients with T1DM. However, more studies are needed to make definitive guidelines on prevention and treatment of osteoporosis in patients with T1DM.

Evaluation of bone mineral density in children with type 1 diabetes mellitus

BACKGROUND

Factors such as vascular/neurological mechanisms, poor glycemic control, abnormalities in vitamin D/calcium, secondary hyperparathyroidism, and hypercalciuria have been blamed for the unfavorable effects of type 1 diabetes mellitus (type 1 DM) on bone health. In this present study, we aimed to evaluate the frequency of low bone mineral density (BMD) in children with type 1 DM.

METHOD

Among 100 type 1 DM patients, a 25-hydroxy vitamin D level of <10 ng/mL was accepted as vitamin D deficiency and the level of 10-20 ng/dL was accepted as vitamin D insufficiency. BMD was measured, and Z-scores were evaluated according to adjusted Turkish standards. Participants with a Z-score of ≤-2 were defined as having low BMD; BMD between -2 and -1 were defined as being in the low range of normality; and values ≥-1 were accepted as normal.

RESULTS

The vitamin D deficiency and insufficiency ratios were 28% and 43%, respectively. Low BMD and BMD in the low range of normality were diagnosed in 10% and 25% of patients, respectively. There was no difference in vitamin D, parathormone, and metabolic control levels between three groups: with normal BMD, low BMD, and BMD in the low range of normality. BMD Z-scores were not different between the pubertal and prepubertal groups.

CONCLUSION

Detailed evaluation should be performed for BMD in the follow-up of DM to prevent complications by decreasing related risks.

A five-year prospective study of bone mineral density in men and women with diabetes: the Fremantle Diabetes Study

To examine longitudinally the effect of diabetes on bone structure and metabolism, we measured bone mineral density (BMD) and turnover markers in 26 type 1 (mean age 49 years) and 27 type 2 (mean age 65 years) diabetic patients without known osteoporosis from a community-based sample at baseline and 5 years later. In the 17 type 1 men, BMD fell at the femoral neck (0.804 ± 0.145 vs. 0.769 ± 0.129 g/cm(2); P = 0.003) with no change at lumbar spine or forearm. In the 11 type 2 women, BMD decreased at all sites except spine (femoral neck 0.779 ± 0.119 vs. 0.742 ± 0.090 g/cm(2); P = 0.019). BMD did not fall at any site in type 1 women or type 2 men. There was an increase in serum alkaline phosphatase and trend to higher serum beta carboxyl-terminal type I collagen telopeptide concentrations in the type 1 patients, and a decrease in free testosterone in the type 1 men. These data show that the rate of demineralization at the femoral neck in type 1 men is similar to that in older post-menopausal type 2 women. Changes in biochemical markers suggest that, in type 1 men, there is ineffective bone formation associated with accelerated bone resorption and lower sex steroid bioavailability. These findings may have implications for the clinical management of young male adults with diabetes.

Effects of raloxifene on bone metabolism in hemodialysis patients with type 2 diabetes

BACKGROUND

Osteoporosis and chronic kidney disease are common conditions in older adults, and often occur concurrently. Bone disease is caused by increased bone turnover accompanying secondary hyperparathyroidism, and by factors such as bone metabolic disorder accompanying kidney disease and postmenopausal or age-related osteoporosis, even in hemodialysis patients. Raloxifene is commonly used for the treatment of postmenopausal osteoporosis in the general population, and may be a treatment option for osteoporosis in hemodialysis patients. However, the effects of raloxifene in hemodialysis patients with type 2 diabetes have not been examined in detail.

OBJECTIVES

This study was performed to investigate the effects of raloxifene on bone turnover markers and bone density in postmenopausal women with type 2 diabetes mellitus who were undergoing hemodialysis in Japan.

PATIENTS AND METHODS

The subjects were 60 female patients on maintenance hemodialysis (non-diabetic, n=30; diabetic, n=30). Raloxifene hydrochloride (60 mg) was administered to 14 diabetic patients and 14 non-diabetic patients for one year, and these patients were compared with control groups (no raloxifene) of 16 diabetic patients and 16 non-diabetic patients. Serum levels of N-terminal cross-linking telopeptide of type I collagen (NTx), bone alkaline phosphatase, and intact parathyroid hormone (iPTH) were measured, and bone density was determined by quantitative heel ultrasound at the speed of sound (SOS) in the calcaneus during this period.

RESULTS

There were no significant differences in the levels of bone turnover markers except for iPTH after treatment of diabetic and non-diabetic patients with raloxifene for one year. SOS increased after treatment with raloxifene, but was significantly decreased in the control groups. Treatment with raloxifene resulted in a significant decrease in NTx and a significant increase in SOS in both diabetic and non-diabetic patients. There were no significant differences between the diabetic and non-diabetic patients who received raloxifene.

CONCLUSIONS

Treatment with raloxifene can suppress reduction in bone density in postmenopausal women with type 2 diabetes who are undergoing hemodialysis.

The effects of vanadium (V) absorbed by Coprinus comatus on bone in streptozotocin-induced diabetic rats

The purpose of this study was to evaluate the effects of vanadium absorbed by Coprinus comatus (VACC) treatment on bone in streptozotocin (STZ)-induced diabetic rats. Forty-five Wistar female rats used were divided into three groups: (1) normal rats (control), (2) diabetic rats, and (3) diabetic rats treated with VACC. Normal and diabetic rats were given physiological saline, and VACC-treated rats were administered VACC intragastrically at doses of 0.18 mg vanadium/kg body weight once daily. Treatments were performed over a 12-week period. At sacrifice, one tibia and one femur were removed, subjected to micro computed tomography (micro-CT) for determination of trabecular bone structure, and then processed for histomorphometry to assess bone turnover. Another femoral was used for mechanical testing. In addition, bone samples were collected to evaluate the content of mineral substances in bones. Treatment with VACC increased trabecular bone volume fraction in diabetic rats. Vanadium-treated animals had significant increases in ultimate load, trabecular thickness, and osteoblast surface. However, vanadium treatment did not seem to affect bone stiffness, bone energy absorption, trabecular separation, and osteoclast number. P levels in the femurs of diabetic rats treated with VACC were significantly higher than those of diabetic animals. Ca levels in diabetic and diabetic rats treated with vanadium showed no obvious changes. In conclusion, our results provide an important proof of concept that VACC may represent a powerful approach to treating or reversing diabetic osteopathy in humans.

Osteoporosis in men with diabetes mellitus

Osteoporosis is more common in women than in men. The prevalence in men is not defined yet; however it is becoming much more recognized as its prevalence and impact have become explicable. It is estimated that around 1% of bone mineral density is lost in men every year. Studies show that secondary osteoporosis is the major cause thus, making it important to define the disorders associated with male osteoporosis. Diabetes is a risk factor for bone fractures. In male patients with diabetes measures should be undertaken such as encouraging exercise, assuring adequate calcium and vitamin D intake, and treating diabetic complications.

Comparison of some of the physicochemical characteristics of type 2 diabetic and normal human bones: a sample study

AIM

The aim of this study was to compare some of the physicochemical characteristics of type 2 diabetic bones (DBs) and normal bones (NBs).

MATERIALS AND METHODS

The organic and inorganic parts of human NBs and DBs were separated using conventional methods, and their physicochemical characteristics were compared using infrared (IR) spectroscopy, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, thermogravimetric analysis, X-ray diffraction (XRD), and scanning electron microscopy (SEM).

RESULTS

The IR spectrum of the collagen part of DBs has showed the presence of carbonyl groups, indicating cross-linking in the α-chain. This was also confirmed by the increased thermal stability (22°C) in DB collagen. The XRD data of the inorganic part of DBs have revealed decreased crystallinity. SEM images of the inorganic part of DBs have shown a porous (weak) nature compared to those of NBs, which exhibited a compact (healthy) nature.

CONCLUSION

The cross-linking in DB collagen molecules and the decreased and defective crystallinity in the inorganic portion of DBs might be the reasons for the increased risk of fracture among diabetic patients.

Effects of vitamin D receptor gene polymorphisms on susceptibility to disease and bone mineral density in Turkish patients with type 1 diabetes mellitus

BACKGROUND

Vitamin D receptor (VDR) gene is regarded as one of the candidate genes for type 1 diabetes mellitus (T1D) susceptibility and of some genetic factors involved in the development of osteoporosis in this group.

STUDY DESIGN

We characterized the VDR gene polymorphism (BsmI, ApaI, TaqI, FokI and Cdx-2 binding site) in a group of Turkish patients with T1D (n=90) and correlated respective VDR genotypes with the bone mass and some parameters of bone turnover.

RESULTS

There were no differences in the genotype frequencies of the BsmI, ApaI, TaqI and Cdx-2 polymorphisms in patients and control subjects. We found a significantly higher prevalence of the F allele/the FF genotype in the patients compared to controls (p=0,0031, odds 1.96 (1,27-3,01)). We observed no difference in markers of bone turnover (Serum levels of osteocalcin, PINP and alkaline phosphatase, urinary levels of calcium/ creatinine and N-telopeptid) among different VDR genotypes. No correlation was found between VDR polymorphisms and DEXA measurements of these patients.

CONCLUSIONS

Although the FF genotype was found to be a risk factor in a Turkish population, elucidation of this result is necessary in other larger study groups drawn from the same ethnic population.

The effect of diabetes mellitus on osseous healing

Diabetes mellitus and, in particular, type 1 diabetes has been associated with impaired osseous wound healing properties. The scope of the present review is to discuss the clinical evidence supporting a higher rate of complications during fracture healing in diabetic patients and the histological evidence indicating impaired potential for intramembranous and endochondral ossification in the presence of uncontrolled experimental diabetes. The article further provides a synthesis of our current understanding of the plausible molecular mechanisms underlying the diabetic bone healing pathophysiology and of the role of insulin treatment in promoting osseous healing in the diabetic status.

Bone health in diabetes: considerations for clinical management

BACKGROUND

The metabolic and endocrine alterations of diabetes adversely affect bone quantity and/or quality and may increase fracture risk.

SCOPE

A survey of the scientific literature on diabetes and bone cited on PubMed/MEDLINE and published in English from January 1970 to November 2008.

FINDINGS

Subjects with type 1 diabetes have reduced bone mass and increased risk of fragility fracture, while those with type 2 diabetes, despite having normal or above-normal bone mineral density (BMD), are susceptible to low-trauma fractures, especially hip fractures. A recent meta-analysis, involving 836 000 subjects and 139 000 incident cases of fracture, found that type 2 diabetes was associated with significantly increased risks of non-vertebral (relative risk 1.2), hip (relative risk 1.7) and foot (relative risk 1.3) fracture. The association with hip fracture persisted after adjustment for age, physical activity and body weight, and was more pronounced in men and in those with long-standing diabetes. Insulin has an anabolic effect on bone, and the qualitatively different effects of type 1 and type 2 diabetes on bone mass are consistent with the opposing insulin-secretory states (hypoinsulinaemia vs. hyperinsulinaemia). However, the existence of an elevated fracture risk in type 2 diabetes, despite the underlying hyperinsulinaemia, suggests the involvement of other potential pathogenic influences (e.g., hyperglycaemia, diabetic complications and lifestyle factors) on bone. Animal studies suggest that diabetic bone may be more fragile than non-diabetic bone. Falls arising from diabetes-related comorbidities are another possible cause of low-trauma fracture. Clinical trial findings, supported by bone marker and bone density data, suggest that the oral antidiabetic agents metformin and glibenclamide significantly lower fracture risk, whereas the thiazolidinediones slightly increase fracture risk in postmenopausal women, but not in men, with type 2 diabetes. Recent preclinical studies have helped elucidate the mechanisms underlying the dynamics of bone remodelling, but more research is needed to improve outcomes for patients.

CONCLUSIONS

Bone health is an important consideration in diabetes, and caution should be exercised in prescribing thiazolidinediones to postmenopausal women with low BMD and patients with prior fracture.

Prevalence and predictors of osteopenia and osteoporosis in adults with Type 1 diabetes

AIMS

To determine the prevalence and biochemical/hormonal determinants of osteopenia and osteoporosis in adults with Type 1 diabetes.

METHODS

One hundred and two patients (52 female, 50 male) with Type 1 diabetes aged 20-71 years underwent cross-sectional assessment of biochemical/hormonal markers of bone metabolism, and bone mineral density (BMD) measurement at forearm, hip and spine using dual energy x-ray absorptiometry. BMD data were available for 102 age- and gender-matched population-based control subjects.

RESULTS

After adjusting for age and body mass index (BMI), osteopenia and osteoporosis were more common at the spine in males with Type 1 diabetes than in control subjects (P = 0.030). In Type 1 males, after adjustment for age and BMI, BMD, T- and Z-scores at the hip, femoral neck and spine were lower compared with age-matched control subjects (P < or = 0.048). Female Type 1 patients and control subjects had similar BMDs and T- and Z-scores at all sites. On multiple linear regression analysis, which adjusted for the natural logarithm of the sex hormone binding globulin concentration, smoking status and alcohol consumption, and (for women) menopausal status, each of BMI, serum ionized calcium and serum alkaline phosphatase (negatively) were independently associated with BMD at the hip and femoral neck in Type 1 diabetic subjects.

CONCLUSIONS

Adult males with Type 1 diabetes have reduced bone density at the hip, femoral neck and spine when compared with age-matched control subjects. Impaired bone formation may occur in Type 1 diabetes.

Negative effect of leptin on bone mass in type 1 diabetes

Studies investigating the effect of leptin on bone mass were inconsistent and some related it to the effect of insulin. We intend in this cross-sectional study to investigate the effect of leptin on bone mass in type 1 diabetic patients. We recruited 42 patients with type 1 diabetes for which we determined weight, height, HbA1c, microalbuminuria, serum leptin, bone mineral content (BMC) and density (BMD), and body composition. The patients had an average age of 20.1 +/- 0.6 years, an average body mass index (BMI) of 23.6 +/- 0.5 kg/cm(2) and an average duration of diabetes of 9.1 +/- 1.0 years. The Z-score was not correlated with HbA1c or duration of the disease, and the average Z-score was not different in patients with microalbuminuria as compared to patients with no reported microalbuminuria. On the other hand, Z-score and BMC correlated negatively with leptin (r = -0.31; p = 0.04 and -0.60, p < 0.01, respectively). These correlations persisted after adjustment for fat mass. We conclude that not metabolic control of diabetes, but serum leptin has a negative effect on bone density in young patients with type 1 diabetes. This negative effect of leptin on bone density maybe, in part, due to deficiency of endogenous insulin secretion in these patients.

The effects of quercetin on bone minerals, biomechanical behavior, and structure in streptozotocin-induced diabetic rats

This study was designed to investigate the effect of quercetin (QE) on bone minerals and biomechanics in insulin-dependent diabetic rats. Diabetes was induced by 50 mg kg(-1) intraperitoneal streptozotocin (STZ) in a single dose. The rats were randomly allotted into four experimental groups: A (control), B (non-diabetic + QE), C (diabetic), and D (diabetic + QE) each containing 10 animals. The diabetic rats received QE (15 mg kg(-1) day(-1)) for 4 weeks following 8 weeks of STZ injection. Blood samples were taken to determine glucose, insulin, calcium, and magnesium levels. The rats' femora were assessed biomechanically at femoral mid-diaphysis and neck. It was found that QE treatment increased insulin, calcium, and magnesium levels. Three-point bending of the femoral mid-diaphysis and necks showed significantly lower maximum load values (F max) in animals in the STZ group than the QE + STZ or control groups (p < 0.05). The results support the conclusion that QE treatment may decrease blood glucose and increase plasma insulin, calcium, and magnesium. QE treatment may also be effective in bone mineral metabolism, biomechanical strength, and bone structure in STZ-induced diabetic rats.

Bone metabolism is linked to disease duration and metabolic control in type 1 diabetes mellitus

This cross-sectional study analyzed bone mineral density (BMD) in children and adolescents with type 1 diabetes mellitus (DM1) and its relationship with metabolic control, duration of disease and bone markers.

METHODS

Forty-four children and adolescents with DM1 (age 8.8+/-4.4 years, disease duration 6.6+/-3.9 years) and 22 healthy children were assessed for BMD of the lumbar spine (L1-L4) by dual energy X-ray absorptiometry; osteocalcin (OC) and carboxy-terminal telopeptide (CTX) were measured in the study group.

RESULTS

The BMD was similar in subjects with (-1.15+/-1.2 S.D.) and without DM1 (-0.85+/-0.88 S.D., p=0.25). After adjustment for weight, height and pubertal development, the BMD was <-2.0 S.D. in only two diabetic patients (4.5%). Bone area (BA) was inversely correlated with the duration of diabetes (p=0.03) and HbA1c (p=0.02). In girls, who presented a worse HbA1c than boys (p<0.01), BMD was inversely correlated with HbA1c (p=0.05). OC and CTX levels were higher in boys (p<0.01) and both inversely correlated with pubertal development (p=0.01), but not with BMD.

CONCLUSIONS

Children and adolescents with DM1 have normal bone mass in the lumbar spine. However, longer diabetes duration and poor metabolic control may have a negative impact on bone mass, requiring further investigation through longitudinal studies.

Increased cathepsin K and tartrate-resistant acid phosphatase expression in bone of streptozotocin-induced diabetic rats

The effect of insulin-dependent diabetes mellitus (IDDM) on bone metabolism was evaluated using the streptozotocin (STZ)-induced diabetic rat 1 week after the induction of diabetes. The urinary excretion of cross-linked N-telopeptides of type I collagen (NTx) and deoxypyridinoline (Dpd) in diabetic rats increased to 3.6-fold and 1.2-fold the control level, respectively. The amount of hydroxyproline and calcium in the distal femur of diabetic rats significantly decreased to 76% and 90% of the control, respectively. The levels of serum osteocalcin and alkaline phosphatase (ALP) activity in the distal femur of the diabetic rats were significantly reduced to about 40% and 70% of the control levels, respectively. The decrease in the expression osteocalcin was observed in distal femur of the diabetic rats, although the level of ALP mRNA was unchanged. The activity and the mRNA level of tartrate-resistant acid phosphatase (TRAP) increased to 1.5- and 2.3-fold the control level, respectively, in distal femur of the diabetic rats. The activity, protein, and mRNA levels of cathepsin K of diabetic rats also elevated to about 2-, 2.3-, and 2-fold the control levels, respectively. These results suggest that IDDM contributes to bone loss through changes in gene expression of TRAP and cathepsin K in osteoclasts as well as osteocalcin in osteoblasts resulting in increased bone resorptive activity and decreased bone formation.

Osteoporosis in patients with diabetes mellitus

Demographic trends with longer life expectancy and a lifestyle characterized by low physical activity and high-energy food intake contribute to an increasing incidence of diabetes mellitus and osteoporosis. Diabetes mellitus is a risk factor for osteoporotic fractures. Patients with recent onset of type 1 diabetes mellitus may have impaired bone formation because of the absence of the anabolic effects of insulin and amylin, whereas in long-standing type 1 diabetes mellitus, vascular complications may account for low bone mass and increased fracture risk. Patients with type 2 diabetes mellitus display an increased fracture risk despite a higher BMD, which is mainly attributable to the increased risk of falling. Strategies to improve BMD and to prevent osteoporotic fractures in patients with type 1 diabetes mellitus may include optimal glycemic control and aggressive prevention and treatment of vascular complications. Patients with type 2 diabetes mellitus may additionally benefit from early visual assessment, regular exercise to improve muscle strength and balance, and specific measures for preventing falls.

Discrepancies in bone mineral density and fracture risk in patients with type 1 and type 2 diabetes--a meta-analysis

INTRODUCTION AND HYPOTHESIS

Diabetes affects bone metabolism. The hypothesis was that type 1 (T1D) and type 2 (T2D) affects BMD and fracture risk differently.

MATERIAL AND METHODS

Pubmed, Embase, and Web of Science were searched using the terms "diabetes", "fracture", and "bone mineral".

RESULTS

Hip fracture risk was increased in T1D (RR = 6.94, 95% CI: 3.25-14.78, five studies) and T2D (1.38, 95% CI: 1.25-1.53, eight studies) compared to subjects without diabetes. The increase in relative hip fracture risk was significantly higher in T1D than in T2D. BMD Z-score was decreased in the spine (mean +/- SEM -0.22 +/- 0.01) and hip (-0.37 +/- 0.16) in T1D and increased in the spine (0.41 +/- 0.01) and hip (0.27 +/- 0.01) in T2D. A meta-regression showed that body mass index (BMI) was a major determinant for BMD in both the spine and hip. Glycated haemoglobin (HbA1C) was not linked to BMD. The increase in fracture risk was higher and BMD lower in patients with complications to diabetes.

CONCLUSIONS

Hip fracture risk is increased in both T1D and T2D, whereas BMD is increased in T2D and decreased in T1D. A common factor such as complications may explain the increase in fracture risk, whereas BMI may ameliorate the increase in fracture risk in T2D.

Women and diabetes

Women with diabetes face unique health challenges throughout their life cycle. Health concerns begin at puberty and continue throughout the reproductive years and later stages of life. Diabetes can have a significant impact on puberty, menstruation, reproduction, and cardiovascular and bone health. All women with diabetes require an individualized reproductive health plan that addresses contraception, the importance of planning pregnancies, and life-style changes. Anticipatory guidance and education in each phase of development can help the woman with diabetes avoid health care problems, reduce her risk of complications, and achieve a health outcome.

Bone density and markers of bone remodeling in type 1 male diabetic patients

AIMS

To assess the prevalence and severity of bone disease in type 1 diabetic patients and to determine serum markers of bone remodeling as well as their relationship with bone mineral density (BMD).

METHODS

BMD [by dual energy x-ray absorptiometry (DXA)] and serum markers of bone remodeling [osteocalcin, c-terminal telopeptide of type I collagen (CTX)], leptin and osteoprotegerin (OPG) were measured in 42 adult males with type 1 diabetes. Twenty-four non-diabetic subjects served as controls.

RESULTS

In 40% of the patients, osteopenia at the lumbar spine (L1-L4) and/or at the left hip was found, and 7% met criteria for osteoporosis. L1-L4 BMD z-score was correlated with age (r=0.365, P=0.018) and a similar trend was observed at left hip. L1-L4 BMD z-score was negatively correlated with CTX and osteocalcin (r=-0.343, P=0.028; r=-0.376, P=0.024, respectively). A significant correlation was evidenced between BMD z-score at both lumbar spine and left hip and leptin values (r=0.343, P=0.03; r=0.395, P=0.012, respectively) but after adjustment for weight this correlation was no longer significant. Osteocalcin, CTX and leptin concentrations were comparable between patients and controls, while OPG concentrations tend to be higher in diabetic subjects (P=0.08). CTX was negatively correlated with age (r=-0.390, P=0.012) and positively correlated with osteocalcin (r=0.696, P<0.001). OPG was positively correlated with age (r=0.507, P=0.001).

CONCLUSION

Our results suggest that in diabetic subjects osteopenia is a relatively frequent complication but bone loss is attenuated with age progression. Whether this is also mediated by OPG and/or leptin remains to be confirmed.

Lower bone mineral content in children with type 1 diabetes mellitus is linked to female sex, low insulin-like growth factor type I levels, and high insulin requirement

CONTEXT

Studies on bone mineral characteristics in children with type 1 diabetes mellitus (T1DM) have generated conflicting results.

OBJECTIVE

Our objective was to investigate bone mineral characteristics in children with T1DM and to analyze their associations with bone metabolism and the IGF-I system.

DESIGN

We recruited a cohort of Caucasian patients with T1DM for at least 3 yr and healthy children between January 2003 and June 2004.

SETTING

This was a university hospital-based study.

PARTICIPANTS

A total of 127 patients and 319 controls aged 6 to 20 yr participated.

METHODS

Dual-energy x-ray absorptiometry was performed in patients and controls. Serum bone alkaline phosphatase, CrossLaps, IGF-I, and IGF-binding protein 3 levels were determined in patients with values analyzed using our normative data from 1150 healthy children.

RESULTS

After adjustment for age, sex, pubertal stage, and body mass index sd score, total body bone mineral content (BMC)/lean body mass was significantly lower in patients than in controls (P < 0.04). This difference was a result of the differences between the girls of the two groups. Girls with T1DM had significantly lower lumbar spine and total body BMC than control girls (P = 0.002), whereas no such difference was observed in boys. Serum bone alkaline phosphatase level was significantly lower in girls than in boys (P = 0.04). Low serum IGF-I levels and the administration of large amounts of insulin were found to have independent deleterious effects on BMC for children of all ages and both sexes, whereas disease duration and glycosylated hemoglobin levels did not.

CONCLUSIONS

A sex-related difference in the impairment of bone mineral characteristics was identified in children with T1DM. Longitudinal studies are required to investigate whether boys may gain slightly less bone mass during skeletal growth.

Bone mineral density and alterations of bone metabolism in children and adolescents with type 1 diabetes mellitus

OBJECTIVES

To analysis bone mineral density (BMD) and bone turnover markers in children and adolescents with type 1 diabetes mellitus (DM1) and to establish possible correlations with duration of the disease and degree of metabolic control.

PATIENTS AND METHODS

Fifty-eight (26 prepubertal, 32 pubertal) children (29 boys) with DM1 (age: 11.7 +/- 3.1 years) and 44 (20 prepubertal, 24 pubertal) healthy children (21 boys) as controls (age: 10.8 +/- 3.2 years) were included in the study. BMD was measured by dual energy X-ray absorptiometry (DEXA). Scans of the lumbar spine (LS2-4) and femoral neck (FN) were carried out. Serum levels of osteocalcin, amino-terminal propeptide of type I procollagen (PINP), and alkaline phosphatase, as markers of bone formation, and urinary calcium/creatinine (Ca/Cr) ratio and levels of N-telopeptide (Ntx), as markers of bone resorption, were assessed. Anthropometrics, duration of DM1, presence of complications, insulin dose, and degree of metabolic control were obtained from the patients' records.

RESULTS

In children with DM1 and controls, the mean measurements of LS2-4 BMD were 0.698 +/- 0.178 g/cm2 and 0.669 +/- 0.192 g/cm2, respectively (p >0.05), and FN-BMD measurements were 0.743 +/- 0.147 g/cm2 and 0.744 +/- 0.170 g/cm2, respectively (p >0.05). Children with DM1 had lower serum levels of calcium, intact parathyroid hormone, osteocalcin and PINP, and higher serum levels of 25-hydroxyvitamin D and urinary Ca/Cr (p <0.05). BMD was not related to any of the markers of bone resorption or formation, duration of the disease, or degree of metabolic control.

CONCLUSIONS

Although we did not establish decreased LS2-4 and FN-BMD measurements in patients with DM1, we found reduced bone formation and increased bone resorption markers in children with DM1. Measurements of serum osteocalcin, PINP, urinary Ntx and Ca/Cr might be useful for long-term follow-up in children and adolescents with DM1.

Bone mineral density and its determinants in diabetes: the Fremantle Diabetes Study

AIMS/HYPOTHESIS

We assessed the effects of type 1 and type 2 diabetes on bone density and metabolism.

MATERIALS AND METHODS

We analysed bone mineral density (BMD) measured at the hip, spine and forearm using dual energy X-ray absorptiometry in 34 patients with type 1 and 194 patients with type 2 diabetes. Patients were from the community-based Fremantle Diabetes Study, and findings for them were compared with those from normal age- and sex-matched control subjects from the local community. Biochemical and hormonal markers of bone metabolism were measured in a subset of 70 patients.

RESULTS

After adjusting for age and BMI, there was a lower BMD at total hip (p<0.001) and femoral neck (p=0.012) in type 1 men vs control subjects, but type 1 women and matched controls had similar BMD at each site. There was a higher BMD at total hip (p=0.006), femoral neck (p=0.026) and forearm (p<0.001) in type 2 women vs control subjects, but diabetes status was not associated with BMD in type 2 men after adjustment for age and BMI. Serum oestradiol, BMI, C-terminal telopeptide of collagen type 1 and male sex were consistently and independently associated with BMD at forearm, hip and femoral neck and explained 61, 55 and 50% of the total variance in BMD, respectively, at these sites. Spine BMD was independently associated with BMI and ln(oestradiol).

CONCLUSIONS/INTERPRETATION

Men with type 1 diabetes may be at increased risk of osteoporosis, while type 2 women appear to be protected even after adjusting for BMI. Low serum oestradiol concentrations may predispose to diabetes-associated osteoporosis regardless of sex.

The effects of vanadium treatment on bone in diabetic and non-diabetic rats

Vanadium-based drugs lower glucose by enhancing the effects of insulin. Oral vanadium drugs are being tested for the treatment of diabetes. Vanadium accumulates in bone, though it is not known if incorporated vanadium affects bone quality. Nine- to 12-month-old control and streptozotocin-induced diabetic female Wistar rats were given bis(ethylmaltolato)oxovanadium(IV) (BEOV), a vanadium-based anti-diabetic drug, in drinking water for 12 weeks. Non-diabetic rats received 0, 0.25 or 0.75 mg/ml BEOV. Groups of diabetic rats were either untreated or treated with 0.25-0.75 mg/ml BEOV as necessary to lower blood glucose in each rat. In diabetic rats, this resulted in a Controlled Glucose group, simulating relatively well-managed diabetes, and an Uncontrolled Glucose group, simulating poorly managed diabetes. Plasma insulin, glucose and triglyceride assays assessed the diabetic state. Bone mineral density (BMD), mechanical testing, mineral assessment and histomorphometry measured the effects of diabetes on bone and the effects of BEOV on non-diabetic and diabetic bone. Diabetes decreased plasma insulin and increased plasma glucose and triglycerides. In bone, diabetes decreased BMD, strength, mineralization, bone crystal length, and bone volume and connectivity. Treatment was effective in incorporating vanadium into bone. In all treated groups, BEOV increased osteoid volume. In non-diabetic bone, BEOV increased cortical bone toughness, mineralization and bone formation. In controlled glucose rats, BEOV lowered plasma glucose and improved BMD, mechanical strength, mineralization, bone crystal length and bone formation rate. In poorly controlled rats, BEOV treatment slightly lowered plasma glucose but did not improve bone properties. These results suggest that BEOV improves diabetes-related bone dysfunction primarily by improving the diabetic state. BEOV also appeared to increase bone formation. Our study found no negative effects of vanadium accumulation in bone in either diabetic or non-diabetic rats at the dose given.

Middle-aged premenopausal women with type 1 diabetes have lower bone mineral density and calcaneal quantitative ultrasound than nondiabetic women

OBJECTIVE

To determine whether middle-aged premenopausal women with type 1 diabetes had more self-reported fractures and lower bone mineral density (BMD) compared with nondiabetic women.

RESEARCH DESIGN AND METHODS

Participants were premenopausal women aged 35-55 years with type 1 diabetes (n = 67; 32.2 +/- 5.3 years duration) and without diabetes (n = 237). Total hip, femoral neck, whole-body, and spine BMD were measured by dual X-ray absorptiometry. Calcaneal broadband ultrasound attenuation (BUA) was assessed with quantitative ultrasound.

RESULTS

Women with type 1 diabetes were more likely to report a fracture after age 20 years compared with nondiabetic women (33.3 vs. 22.6%; age-adjusted odds ratio 1.89 [95% CI 1.02-3.49]). Type 1 diabetes was associated with lower total hip BMD (0.890 vs. 0.961 g/cm2; P < 0.001), femoral neck BMD (0.797 vs. 0.847 g/cm2; P = 0.001), whole-body BMD (1.132 vs. 1.165 g/cm2; P < 0.01), and lower calcaneal BUA (71.6 vs. 84.9 dB/MHz; P < 0.001) after multivariate adjustment. BMD was 3-8% lower in type 1 diabetic compared with control women and calcaneal BUA was 15% lower. Spine BMD and biomarkers of bone remodeling were not significantly different between groups. In the type 1 diabetic women, reduced monofilament detection and blindness were both associated with lower BMD.

CONCLUSIONS

Lower BMD in premenopausal women with type 1 diabetes may substantially increase their risk of developing osteoporosis after menopause. Type 1 diabetic women should be targeted for osteoporosis screening and possible fracture prevention as they transition through menopause.

Non-insulin-dependent diabetes, bone mineral density, and cardiovascular risk factors

People with Type 2 diabetes have bone mass alterations and may have a higher risk of hip fractures. Moreover, they have increased cardiovascular risk factors. The objective of this paper is to investigate the association among non-insulin-dependent diabetes, bone mineral density (BMD), and cardiovascular risk factors. Ninety-two patients (36 males and 56 females) were studied and cardiovascular risk factors were measured: total cholesterol, triglycerides, lipoprotein(a), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), glucose, HbA1c, and microalbuminuria. The densitometric studies were carried out in the calcaneal region using a DEXA densitometer. The diabetic women had a higher BMD than the control group (0.502 +/- 0.127 vs. 0.408 +/- 0.102, P = .027). The women showed a positive relationship between BMD and triglycerides (r =. 478, P = .0001) and a negative relationship with HDL-C (r = -.322, P = .016). The men had a BMD similar to that of the control group, and there was no relationship with the cardiovascular risk factors. When a multivariate logistic regression analysis was performed with the presence of osteoporosis as a dependent variable and each lipid level, age, sex, and BMI as independent variables, only age and BMI were found to be associated with the presence of osteopososis. The diabetic women had a higher BMD than the controls, and there was no relationship between osteoporosis and cardiovascular risk factors in diabetics.

Quantitative ultrasound of proximal phalanxes in patients with type 1 diabetes mellitus

The influence of duration of diabetes and metabolic control on phalangeal quantitative ultrasound (QUS) was evaluated in a group of children and adolescents with type 1 diabetes. Eighty-six patients (mean age 11.9 years; mean duration 4.3 years) were studied. Daily calcium intake was assessed by means of a questionnaire. Amplitude-dependent speed of sound (AD-SoS) was measured at the phalanxes of the non-dominant hand and expressed as a z-score. Linear and multivariate correlations with duration of diabetes and, short term and long term metabolic control were sought. AD-SoS z-score was -0.43+/-1.4 (95% CI, -0.73; -0.13). Nine subjects had values below -2S.D. Daily calcium intake was 1042+/-456 mg/day; 47 subjects (54.6%) were below the recommended levels. A negative correlation was found between AD-SoS z-score and duration (r, -0.33, P=0.002) or metabolic control (HbA1c-last year r, -0.32, P=0.002; HbA1c-whole duration, r, -0.40; P=0.003). Negative AD-SoS z-scores depended significantly and directly on duration and quality of metabolic control, even when controlled for calcium intake. In conclusion, the architectural organization of bone was impaired in 10.5% patients. Duration of diabetes and poor metabolic control were the main determinants affecting AD-SoS. QUS may be a useful tool in the screening of bone disturbance in young patients with diabetes. Optimization of metabolic control is required to prevent osteoporosis.

Effects of dietary intake and life style on bone density in patients with diabetes mellitus type 2

OBJECTIVE

The aim of our study was to investigate the relation among glycemic control, lifestyle and dietary intake with bone mineral density in patients with diabetes mellitus type 2.

DESIGN

Cross-sectional study.

SETTING

Tertiary care hospital.

PARTICIPANTS

A cross-sectional study in a tertiary care hospital was performed. Ninety-two patients attending our diabetes service (56 females/36 males) with diabetes mellitus type 2 were enrolled in a consecutive way. The inclusion criteria were diabetes diagnosed >40 years of age, with type 2 diabetes defined in accordance with the criteria of the American Diabetes Association and no use of dietary supplements. Body mass index, waist-to-hip ratio, glucose level, and HbA1c levels were assessed in all patients. X-ray densitometry of the calcaneal region and a 3-days written food record keeping, and a qualitative questionnaire of lifestyle were also performed.

RESULTS

A total of 21.7% of patients had osteoporosis (T score <2.5 SD). Patients were overweight with a high BMI and a medium glucose control. Patients with osteoporosis were older than those without osteoporosis (67.8 +/- 6.9 vs. 62.1 +/- 9.2 years; p < 0.05). Significant differences were detected between patients without and with osteoporosis in calcium intake (1,219.37 +/- 387 vs. 839 +/- 251 mg/day; p < 0.05) and zinc intake (9.23 +/- 3.5 vs. 13.3 +/- 6.9 mg/day; p < 0.05), respectively. No differences were detected in other dietary dairy intakes. In correlation analysis age (r = -0.23; p < 0.05) and BMI (r = 0.48; p < 0.05) was correlated with BMD. In univariate analysis with dicotomic variables, only exercise was positive associated with osteoporotic status (87.5% exercise habit in patients without osteoporosis and 25% exercise habit in patients with osteoporosis; p < 0.05). In a logistic model with the dependent variable (osteoporosis), remained in the final model dietary dairy intake of calcium and zinc, BMI, age and exercise. Exercise, calcium intake and BMI were protective factors. Zinc intake, and age were risk factors.

CONCLUSIONS

Exercise, calcium intake, body mass index had a protective role in bone mineral density in patients with diabetes mellitus type 2. Zinc intake and age were risk factors in our population.

Diabetes Mellitus: Does it Affect Bone?

Both diabetes and fractures affect a large proportion of older adults. Recent cohort studies indicate that diabetes itself is associated with increased risk of fracture of the hip, proximal humerus, and foot. Observational studies and animal models suggest that decreased bone strength in diabetes may contribute to fracture risk but this remains a controversial issue. Type 1 diabetes is associated with modest reductions in bone mineral density (BMD) but type 2 diabetes is often characterized by elevated BMD. This paradox of higher BMD but increased fracture risk in type 2 diabetes may be explained by a combination of more frequent falls and poorer bone quality. Diabetes can impact bone through multiple pathways, some with contradictory effects, including obesity, changes in insulin levels, higher concentrations of advanced glycation end products in collagen, hypercalciuria associated with glycosuria, reduced renal function, lower insulin-like growth factor-I, microangiopathy, and inflammation. A better understanding of how diabetes metabolism and treatments affect bone would improve fracture prevention efforts in older diabetic adults.

Osteopenia in insulin-dependent diabetes mellitus; prevalence and aspects of pathophysiology

The objective was to evaluate the prevalence and severity of osteopenia in patients with uncomplicated insulin-dependent diabetes mellitus (IDDM) and to obtain more information on the pathophysiology of diabetic osteopenia. In 35 patients with uncomplicated IDDM (21 men and 14 women; age 37.6+/-9.9 yr; duration of disease 8.5+/-3.5 years) bone mineral density was measured by dual energy X-ray absorptiometry (DEXA). In addition, markers of bone formation [plasma insulin-like growth factor I (IGF-I), serum alkaline phosphatase (ALP), serum bone alkaline phosphatase (BAP) and serum osteocalcin] and bone resorption [urinary excretion of calcium and of the cross-linked N-telopeptide of type 1 collagen, both corrected for the excretion of creatinine] were measured in the diabetic patients and in 33 healthy controls, matched for sex, age, height, weight and body mass index (BMI). In 67% of the diabetic men and 57% of the diabetic women osteopenia of the femoral neck and/or the lumbar spine (T-value < or = -1 SD) was present. Fourteen percent of the male patients, but none of the female patients, met the criteria for osteoporosis (T-value < or = -2.5 SD). In the whole group of diabetic patients the mean plasma IGF-I level tended to be lower (p<0.10) as compared to that in the controls. In the diabetic patients with femoral neck osteopenia, the mean plasma IGF-I level was significantly lower (p<0.05) than in those without osteopenia at this site. There were no differences in the mean serum ALP, BAP and osteocalcin levels between the diabetic patients and the controls, nor between the diabetic patients with and without femoral neck osteopenia. Considering only the male diabetic patients, significantly lower mean plasma IGF-I (-26%), serum ALP (-24%) and serum osteocalcin (-38%) levels were present in the patients with femoral neck osteopenia than in those without osteopenia at this site, suggesting lowered bone formation. The bone resorption markers were similar in all (sub)groups of diabetic patients and not different between diabetic patients and controls. Bone mineral density (BMD) did not correlate with plasma levels of glycosylated hemoglobin (HbA1c). BMD values were not related to any of the bone resorption or formation markers, except for plasma IGF-I both in the femoral neck (r=+0.38, p=0.026) and the lumbar spine (r=+0.34, p=0.043). Our data demonstrate that at least in male patients with IDDM, osteopenia is the consequence of a lowered bone formation with a predominance of bone resorption over formation.

Correlations between insulin sensitivity and bone mineral density in non-diabetic men

AIMS

To investigate relationships between bone mineral density (BMD), insulin secretion and insulin sensitivity, controlling for body composition, in view of data suggesting that hyperglycaemia [corrected] leads to decreased osteoblast proliferation and a negative calcium balance and that insulin stimulates osteoblast differentiation and collagen synthesis, with no clear evidence if this response in impaired in insulin resistance.

METHODS

Femur and whole body (WB) BMD was measured in 55 male patients with ischaemic heart disease and 40 healthy men, using a Hologic QDR-2000 densitometer. Insulin sensitivity (Si) was estimated as the rate of glucose disappearance divided by the area under the insulin curve during an intravenous glucose tolerance test.

RESULTS

Insulin and C-peptide levels were not correlated with BMD, but Si was a significant predictor of femur (log, r = 0.35) and WB BMD (log r = 0.29, both P<0.01), even after controlling for weight and age. Fat mass (FM) was a predictor of BMD (femur: r = 0.33 P<0.01, WB: r = 0.43 P<0.001). In the femur the association with FM disappeared when log(Si) was entered in the regression. Lean body mass (LBM) contributed significantly to BMD (r = 0.50 and r = 0.66, both P<0.001).

CONCLUSIONS

These results are compatible with a direct influence of lean body mass on bone, while the impact of fat mass may consist of insulin resistance with increased insulin exposure of bone. It is hypothesized that patients with insulin resistance in the metabolic pathway do not exhibit resistance to the skeletal actions of insulin.