Selective osteoblast overexpression of IGF-I in mice prevents low protein-induced deterioration of bone strength and material level properties

Protein deficiency is frequently observed in elderly osteoporotic patients. Undernutrition leads to decreased levels of IGF-I, an important factor in regulating bone homeostasis throughout life. IGF-I is produced in the liver and locally in the skeleton. We hypothesized that increasing IGF-I expression in the osteoblasts, the bone forming cells, would protect the skeleton from the negative effects of a low-protein diet. To test our hypothesis, we employed a mouse model in which IGF-I was overexpressed exclusively in osteoblasts and fed either a 15% (normal) or a 2.5% (low) protein isocaloric diet to the transgenic (TG) mice and their wild-type (WT) littermates for 8 weeks. Blood was collected for biochemical determinations and weight was monitored weekly. Bones were excised for microstructural analysis (μCT), as well as biomechanical and material level properties. Histomorphometric analysis was performed for bone formation parameters. A low protein diet decreased body weight, circulating IGF-I and osteocalcin levels regardless of genotype. Overexpression of IGF-I in the osteoblasts was, however, able to protect the negative effects of low protein diet on microstructure including tibia cortical thickness and volumetric density, and on bone strength. Overexpression of IGF-I in osteoblasts in these mice protected the vertebrae from the substantial negative effects of low protein on the material level properties as measured my nanoindentation. TG mice also had larger overall geometric properties than WT mice regardless of diet. This study provides evidence that while a low protein diet leads to decreased circulating IGF-I, altered microstructure and decreased bone strength, these negative effects can be prevented with IGF-I overexpression exclusively in bone cells.

Partial adherence: a new perspective on health economic assessment in osteoporosis

Partial adherence in osteoporosis increases the risk for fragility fracture and has considerable impact on cost-effectiveness. This review highlights a number of avenues for further research, such as improved definition of thresholds of compliance and persistence, as well as gap length, offset times, and fraction of benefit.

INTRODUCTION

A number of economic models have been developed to evaluate osteoporosis therapies and support decisions regarding efficient allocation of health care resources. Adherence to treatment is seldom incorporated in these models, which may reduce their validity for decision-making since adherence is poor in real-world clinical practice.

METHODS

An ad hoc working group of the European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis met to review key issues concerning the incorporation of partial adherence in health economic models.

RESULTS

Observational data have shown that poor adherence is associated with an increase in the risk for fragility fracture. Health economic modelling indicates that full adherence is associated with more quality-adjusted life years gained than partial adherence, as well as higher treatment costs and lower fracture-related costs. Although adherence appears as an important driver of cost-effectiveness, the effect is dependent on a range of other variables, such as offset time, fraction of benefit, fracture risk, fracture efficacy, fracture-related costs, and drug cost, some of which are poorly defined. Current models used to evaluate cost-effectiveness in osteoporosis may oversimplify the contributions of compliance and persistence.

CONCLUSION

Partial adherence has a significant impact on cost-effectiveness. Further research is required to optimise thresholds of compliance and persistence, the impact of gap length, offset times, and fraction of benefit.

Fractures during childhood and adolescence in healthy boys: relation with bone mass, microstructure, and strength

CONTEXT

In healthy boys, fractures result from trauma of various severity, suggesting contribution of an intrinsic biomechanical fragility.

OBJECTIVES

Our objective was to characterize bone mineral mass, microstructure, and strength in boys with and without fractures.

PARTICIPANTS AND DESIGN

We followed 176 healthy boys from 7.4 ± 0.5 to 15.2 ± 0.5 (mean ± sd) yr of age.

OUTCOMES

Areal (a) bone mineral density (BMD) was measured by dual-energy x-ray absorptiometry at radius metaphysis and diaphysis, total hip, femoral neck and diaphysis, and L2-L4 vertebrae. Volumetric (v) BMD and microstructure were assessed by high-resolution peripheral computerized tomography at both distal tibia and radius. Bone strength was evaluated by micro-finite element analysis.

RESULTS

A total of 156 fractures were recorded in 87 of 176 boys with peak incidence between 10 and 13 yr. At 7.4 yr, subjects with fractures had lower aBMD in all sites and at 15.2 yr in femoral and spinal, but not in radius, sites. At that age, boys with fractures displayed lower trabecular (Tb) vBMD (P = 0.029) and number (P = 0.040), stiffness (P = 0.024), and failure load (P = 0.016) at distal tibia, but not distal radius. Odds ratios of fracture risk per 1 sd decrease were 1.80 (P = 0.006) for femoral neck aBMD and 1.46 (P = 0.038) for distal tibia Tb vBMD, 1.59 (P = 0.031) for Tb number, 1.53 (P = 0.072) for stiffness, and 1.60 (P = 0.056) for failure load.

CONCLUSION

In a homogeneous cohort of healthy boys, fractures recorded until 15.2 ± 05 yr of age were associated with lower femoral neck aBMD and with lower distal tibia trabecular vBMD and number, stiffness and failure load. These deficits in bone mineral mass, microstructure and strength could contribute to the occurrence of fractures during growth.

Pubertal timing and body mass index gain from birth to maturity in relation with femoral neck BMD and distal tibia microstructure in healthy female subjects

Childhood body mass index (BMI) gain is linked to hip fracture risk in elderly. In healthy girls, menarcheal age is inversely related to BMI gain during childhood and to femoral neck areal bone mass density (aBMD) and distal tibia structural components at maturity. This study underscores the importance of pubertal timing in age-related fragility fracture risk.

INTRODUCTION

Recent data point to a relationship between BMI change during childhood and hip fracture risk in later life. We hypothesized that BMI development is linked to variation in pubertal timing as assessed by menarcheal age (MENA) which in turn, is related to peak bone mass (PBM) and hip fracture risk in elderly.

METHODS

We studied in a 124 healthy female cohort the relationship between MENA and BMI from birth to maturity, and DXA-measured femoral neck (FN) aBMD at 20.4 year. At this age, we also measured bone strength related microstructure components of distal tibia by HR-pQCT.

RESULTS

At 20.4 ± 0.6 year, FN aBMD (mg/cm(2)), cortical thickness (μm), and trabecular density (mg HA/cm(3)) of distal tibia were inversely related to MENA (P = 0.023, 0.015, and 0.041, respectively) and positively to BMI changes from 1.0 to 12.4 years (P = 0.031, 0.089, 0.016, respectively). Significant inverse (P < 0.022 to <0.001) correlations (R = -0.21 to -0.42) were found between MENA and BMI from 7.9 to 20.4 years, but neither at birth nor at 1.0 year. Linear regression indicated that MENA Z-score was inversely related to BMI changes not only from 1.0 to 12.4 years (R = -0.35, P = 0.001), but also from 1.0 to 8.9 years, (R = -0.24, P = 0.017), i.e., before pubertal maturation.

CONCLUSION

BMI gain during childhood is associated with pubertal timing, which in turn, is correlated with several bone traits measured at PBM including FN aBMD, cortical thickness, and volumetric trabecular density of distal tibia. These data complement the reported relationship between childhood BMI gain and hip fracture risk in later life.

Interpretation and use of FRAX in clinical practice

The introduction of the WHO FRAX® algorithms has facilitated the assessment of fracture risk on the basis of fracture probability. Its use in fracture risk prediction has strengths, but also limitations of which the clinician should be aware and are the focus of this review

INTRODUCTION

The International Osteoporosis Foundation (IOF) and the International Society for Clinical Densitometry (ISCD) appointed a joint Task Force to develop resource documents in order to make recommendations on how to improve FRAX and better inform clinicians who use FRAX. The Task Force met in November 2010 for 3 days to discuss these topics which form the focus of this review.

METHODS

This study reviews the resource documents and joint position statements of ISCD and IOF.

RESULTS

Details on the clinical risk factors currently used in FRAX are provided, and the reasons for the exclusion of others are provided. Recommendations are made for the development of surrogate models where country-specific FRAX models are not available.

CONCLUSIONS

The wish list of clinicians for the modulation of FRAX is large, but in many instances, these wishes cannot presently be fulfilled; however, an explanation and understanding of the reasons may be helpful in translating the information provided by FRAX into clinical practice.

Adverse reactions and drug-drug interactions in the management of women with postmenopausal osteoporosis

The pharmacological management of disease should involve consideration of the balance between the beneficial effects of treatment on outcome and the probability of adverse effects. The aim of this review is to explore the risk of adverse drug reactions and drug-drug interactions with treatments for postmenopausal osteoporosis. We reviewed evidence for adverse reactions from regulatory documents, randomized controlled trials, pharmacovigilance surveys, and case series. Bisphosphonates are associated with gastrointestinal effects, musculoskeletal pain, and acute-phase reactions, as well as, very rarely, atrial fibrillation, atypical fracture, delayed fracture healing, osteonecrosis of the jaw, hypersensitivity reactions, and renal impairment. Cutaneous effects and osteonecrosis of the jaw are of concern for denosumab (both very rare), though there are no pharmacovigilance data for this agent yet. The selective estrogen receptor modulators are associated with hot flushes, leg cramps, and, very rarely, venous thromboembolism and stroke. Strontium ranelate has been linked to hypersensitivity reactions and venous thromboembolism (both very rare) and teriparatide with headache, nausea, dizziness, and limb pain. The solidity of the evidence base depends on the frequency of the reaction, and causality is not always easy to establish for the very rare adverse reactions. Drug-drug interactions are rare. Osteoporosis treatments are generally safe and well tolerated, though they are associated with a few very rare serious adverse reactions. While these are a cause for concern, the risk should be weighed against the benefits of treatment itself, i.e., the prevention of osteoporotic fracture.

Joint Official Positions of the International Society for Clinical Densitometry and International Osteoporosis Foundation on FRAX(®). Executive Summary of the 2010 Position Development Conference on Interpretation and use of FRAX® in clinical practice

The International Society for Clinical Densitometry (ISCD) and the International Osteoporosis Foundation (IOF) convened the FRAX(®) Position Development Conference (PDC) in Bucharest, Romania, on November 14, 2010, following a two-day joint meeting of the ISCD and IOF on the "Interpretation and Use of FRAX(®) in Clinical Practice." These three days of critical discussion and debate, led by a panel of international experts from the ISCD, IOF and dedicated task forces, have clarified a number of important issues pertaining to the interpretation and implementation of FRAX(®) in clinical practice. The Official Positions resulting from the PDC are intended to enhance the quality and clinical utility of fracture risk assessment worldwide. Since the field of skeletal assessment is still evolving rapidly, some clinically important issues addressed at the PDCs are not associated with robust medical evidence. Accordingly, some Official Positions are based largely on expert opinion. Despite limitations inherent in such a process, the ISCD and IOF believe it is important to provide clinicians and technologists with the best distillation of current knowledge in the discipline of bone densitometry and provide an important focus for the scientific community to consider. This report describes the methodology and results of the ISCD-IOF PDC dedicated to FRAX(®).

["Jaques-Dalcroze eurhythmics" improves gait and prevents falls in the elderly]

Given the significant health and socioeconomic consequences of falls, to develop and promote effective falls prevention strategies among older adults represents a major issue. Jaques-Dalcroze eurhythmics is a music education program through movement method developed in Geneva, Switzerland, in the early 20th century. This new exercise form, adapted for elderly people, features various multitask exercises performed to the rhythm of improvised piano music and mainly challenge gait and balance, but also memory, attention and coordination. We report here the results of a randomized controlled trial conducted in Geneva showing that Jaques-Dalcroze eurythmics practice can improve gait performance under single and dual-task conditions, and balance, as well as reduce both rate of falls and the risk of falling in at-risk elderly community-dwellers.

[General trend of hip fractures]

Osteoporosis constitutes a major public health problem and hip fractures are a major cause of burden associated with osteoporosis in terms of mortality, disability, and costs. Since around 1990, a trend for a decrease of the age-adjusted incidence of hip fractures has been observed in western countries, particularly in women. In Geneva, with a confirmation at the Swiss level, a similar secular trend was observed. Nevertheless, due to the ageing of the population, this decrease of the incidence of hip fracture will probably not be sufficient to reduce the absolute number of these fractures over the next decades. Furthermore, age-adjusted hospitalizations in Switzerland for major non-hip osteoporotic fractures have continued to increase these last years.

[Selective serotonin reuptake inhibitors (SSRI) and osteoporosis]

Selective serotonin reuptake inhibitors (SSRI) represent the first-line treatment of depression. Several studies demonstrate that use of therapeutical doses of SSRI is associated with a decreased bone mineral density (BMD) and an increased risk of fracture. Mechanisms of action of SSRI on bone tissue are not totally clarified. These treatments would be associated with an increased risk of falls and would also have a direct effect on bone metabolism. Regarding proofs existing of the implication of SSRI on osteoporosis, while waiting for larger-scale prospective studies, it appears reasonable that practitioners assess bone loss within risk groups of patients treated with SSRI.

Calcitropic hormones and IGF-I are influenced by dietary protein

Elderly men and women with protein deficiencies have low levels of circulating IGF-I, and it is likely this contributes to reduced bone formation and increased bone resorption. We hypothesized that calcitropic hormones are involved in this effect and are affected by dietary protein. We therefore investigated the influence of a low-protein diet on the PTH-1,25-dihydroxyvitamin D3 [1,25(OH)₂D₃] axis and IGF-I in rats, using pamidronate to block resorption that normally contributes to mineral homeostasis. We fed 6-month-old Sprague Dawley female rats isocaloric diets containing 2.5% or 15% casein for 2 wk. Pamidronate was then administered sc (0.6 mg/kg/) for 5 d. Blood samples were collected at different time points. Serum 1,25(OH)₂D₃, IGF-I, PTH, calcium, and phosphorus were determined in all rats; vertebral bone strength and histomorphometric analysis were performed in rats subject to the longest low-protein diets. We found 2 wk of low protein increased PTH levels, decreased 1,25(OH)₂D₃, calcium, and IGF-I, suggesting that increased PTH compensates for low-protein-induced decreases in 1,25(OH)₂D₃. Pamidronate augmented the increased PTH after 8 wk of low protein and prevented the 1,25(OH)₂D₃ decrease. IGF-I remained low. Protein malnutrition induced decreases in relative bone volume and trabecular thickness, which was prevented by pamidronate. Maximal load was reduced by protein restriction, but rescued by pamidronate. In summary, the low protein diet resulted in hyperparathyroidism, a reduction in circulating levels of IGF-I, and reduced 1,25(OH)₂D₃ despite hyperparathyroidism. Blocking resorption resulted in further increases in PTH and improved microarchitecture and biomechanical properties, irrespective of vitamin D status or protein intake.

Early post-transplantation hypophosphatemia is associated with elevated FGF-23 levels

BACKGROUND

We examined the hypothesis that high FGF-23 levels early after transplantation contribute to the onset of hypophosphatemia, independently of parathyroid hormone (PTH) and other factors regulating phosphate metabolism.

METHODS

We measured serum phosphate levels (sPi), renal tubular reabsorption of Pi (TmPi/GFR), estimated GFR (eGFR), intact PTH (iPTH), calcitriol, intact (int) and C-terminal (Cter) FGF-23, dietary Pi intake and cumulative doses of glucocorticoids in 69 patients 12 days (95% confidence interval, 10-13) after renal transplantation.

RESULTS

Hypophosphatemia was observed in 43 (62%) of the patients 12 days after transplantation. Compared with non-hypophosphatemic subjects, their post-transplantation levels of intact and CterFGF-23 were higher (195 (108-288) vs 48 (40-64) ng/l, P<0.002 for intFGF-23; 205 (116-384) vs 81 (55-124) U/ml, P<0.002, for CterFGF-23). In all subjects, Cter and intFGF-23 correlated inversely with sPi (r=-0.35, P<0.003; -0.35, P<0.003, respectively), and TmPi/GFR (r=-0.50, P<0.001; -0.54, P<0.001, respectively). In multivariate models, sPi and TmPi/GFR were independently associated with FGF-23, iPTH and eGFR. Pre-transplant iPTH levels were significantly higher in patients developing hypophosphatemia after renal transplantation. Pre-transplant levels of FGF-23 were not associated with sPi at the time of transplantation.

CONCLUSION

In addition to PTH, elevated FGF-23 may contribute to hypophosphatemia during the early post-renal transplant period.

Bisphosphonates for post-menopausal osteoporosis: are they all the same?

The primary goal of treatment for post-menopausal osteoporosis (PMO) is reduction in fracture risk. Therefore, clinicians must recommend therapies that are safe and have proven anti-fracture efficacy. Bisphosphonates have long been established as first-line therapy for osteoporosis and several of these drugs significantly reduce osteoporotic fracture risk. However, choosing among different bisphosphonates can represent a difficult clinical decision. This review outlines the pharmacology of various bisphosphonates, discusses how their pharmacological characteristics affect their efficacy, and summarizes clinical safety and efficacy data. Clinical trial data and the opinions of expert bodies suggest that alendronate, risedronate, ibandronate and zoledronic acid all provide fracture protection for patients with PMO. However, there are differences among these agents. For example, all four agents have demonstrated efficacy in preventing vertebral fractures, but only zoledronic acid and risedronate significantly reduce non-vertebral fracture risk in pivotal trials. Moreover, reduction in hip fracture risk has only been established for alendronate, risedronate and zoledronic acid. Current data suggest that ibandronate and zoledronic acid have the most persistent antifracture effect. Bisphosphonates have been associated with a number of side effects, the evidence for which is summarized in this review. The most pertinent of these when choosing a bisphosphonate for a particular patient are the well-documented associations between gastrointestinal adverse events and oral administration, and between acute phase reactions and intravenous administration. Ultimately, selection of a specific bisphosphonate for treatment of PMO should be based on efficacy, risk profile, cost-effectiveness and patient preference.

Study of a-Si:H / c-Si Heterojunctions for PV Applications

a-Si:H / c-Si heterojunction diodes were produced by PECVD with varying amorphous silicon layer thickness and hydrogen dilution of the gas phase. An accurate determination of the growth rate also in the initial stages of the deposition was made possible by an original chemical method based on the dissolution of the films followed by spectroscopical analysis of the obtained solution.

The electrical characterization of the diodes confirms the generation - recombination - multitunneling nature of the transport. Although H2 dilution is important, however, beyond a certain level it is detrimental for the junction quality, probably due to the transition to a microcrystalline phase deposition. Solar cells were also produced, the best results being an open circuit voltage of 610 mV and an intrinsic efficiency of 14.2%.

Subtrochanteric fractures after long-term treatment with bisphosphonates: a European Society on Clinical and Economic Aspects of Osteoporosis and Osteoarthritis, and International Osteoporosis Foundation Working Group Report

This paper reviews the evidence for an association between atypical subtrochanteric fractures and long-term bisphosphonate use. Clinical case reports/reviews and case-control studies report this association, but retrospective phase III trial analyses show no increased risk. Bisphosphonate use may be associated with atypical subtrochanteric fractures, but the case is yet unproven.

INTRODUCTION

A Working Group of the European Society on Clinical and Economic Aspects of Osteoporosis and Osteoarthritis and the International Osteoporosis Foundation has reviewed the evidence for a causal association between subtrochanteric fractures and long-term treatment with bisphosphonates, with the aim of identifying areas for further research and providing recommendations for physicians.

METHODS

A PubMed search of literature from 1994 to May 2010 was performed using key search terms, and articles pertinent to subtrochanteric fractures following bisphosphonate use were analysed.

RESULTS

Several clinical case reports and case reviews report a possible association between atypical fractures at the subtrochanteric region of the femur in bisphosphonate-treated patients. Common features of these 'atypical' fractures include prodromal pain, occurrence with minimal/no trauma, a thickened diaphyseal cortex and transverse fracture pattern. Some small case-control studies report the same association, but a large register-based study and retrospective analyses of phase III trials of bisphosphonates do not show an increased risk of subtrochanteric fractures with bisphosphonate use. The number of atypical subtrochanteric fractures in association with bisphosphonates is an estimated one per 1,000 per year. It is recommended that physicians remain vigilant in assessing their patients treated with bisphosphonates for the treatment or prevention of osteoporosis and advise patients of the potential risks.

CONCLUSIONS

Bisphosphonate use may be associated with atypical subtrochanteric fractures, but the case is unproven and requires further research. Were the case to be proven, the risk-benefit ratio still remains favourable for use of bisphosphonates to prevent fractures.

Socioeconomic and living conditions are determinants of hip fracture incidence and age occurrence among community-dwelling elderly

In this prospective, 10-year study in community-dwelling elderly aged 50 years and over, hip fracture incidence and accordingly age at hip fracture were inversely associated with the area-level income, independently of the geographical area. Age at hip fracture also depended of marital status but in a gender-specific way.

PURPOSE

The purpose of this study is to investigate the impact of socioeconomic and living conditions on hip fracture incidence and age occurrence among community-dwelling elderly.

METHOD

Between January 1991 and December 2000, 2,454 hip fractures were recorded in community-dwelling adults aged 50 years and over in the Geneva University Hospital, State of Geneva, Switzerland. Median annual household income by postal code of residence (referred to as area-level income) based on the 1990 Census was used as a measure of socioeconomic condition and was stratified into tertiles (< 53,170; 53,170-58,678; and ≥ 58,678 CHF). Hip fracture incidence and age occurrence were calculated according to area-level income categories and adjusted for confounding factors among community-dwelling elderly.

RESULTS

Independently of the geographical area (urban versus rural), community-dwelling persons residing in areas with the medium income category presented a lower hip fracture incidence [OR 0.91 (0.82-0.99), p = 0.049] compared to those from the lowest income category. Those in the highest income category had a hip fracture at a significant older age [+1.58 (0.55-2.61) year, p = 0.003] as compared to those in the lowest income category. Age at hip fracture also depended on marital status but in a gender-specific way, with married women fracturing earlier.

CONCLUSIONS

These results indicate that incidence and age occurrence of hip fracture are influenced by area-level income and living conditions among community-dwelling elderly. Prevention programs may be encouraged in priority in communities with low income.

[Osteoporosis]

Calcium supplements should be used according to the dietary intakes. Daily vitamin D supplements have beneficial on bone and extraskeletal effects. Denosumab is registered in Switzerland for the treatment of postmenopausal osteoporosis and to prevent bone loss induced by sex hormone deprivation therapies in men and women. Zoledronate has a long-term efficacy on bone resorption in postmenopausal women and prevents bone loss induced by sex hormone deprivation therapies in both sexes. Teriparatide exerts beneficial effects on maxillary bone. Odanacatib decreases bone resorption and increases bone mineral density. Cinacalcet could be used as long-term treatment in case of hyperparathyroidism. Adverse events associated with the use of bisphosphonate are still under discussion. Strontium ranelate will not be introduced in Switzerland.

Effect of music-based multitask training on gait, balance, and fall risk in elderly people: a randomized controlled trial

BACKGROUND

Falls occur mainly while walking or performing concurrent tasks. We determined whether a music-based multitask exercise program improves gait and balance and reduces fall risk in elderly individuals.

METHODS

We conducted a 12-month randomized controlled trial involving 134 community-dwelling individuals older than 65 years, who are at increased risk of falling. They were randomly assigned to an intervention group (n = 66) or a delayed intervention control group scheduled to start the program 6 months later (n = 68). The intervention was a 6-month multitask exercise program performed to the rhythm of piano music. Change in gait variability under dual-task condition from baseline to 6 months was the primary end point. Secondary outcomes included changes in balance, functional performances, and fall risk.

RESULTS

At 6 months, there was a reduction in stride length variability (adjusted mean difference, -1.4%; P < .002) under dual-task condition in the intervention group, compared with the delayed intervention control group. Balance and functional tests improved compared with the control group. There were fewer falls in the intervention group (incidence rate ratio, 0.46; 95% confidence interval, 0.27-0.79) and a lower risk of falling (relative risk, 0.61; 95% confidence interval, 0.39-0.96). Similar changes occurred in the delayed intervention control group during the second 6-month period with intervention. The benefit of the intervention on gait variability persisted 6 months later.

CONCLUSION

In community-dwelling older people at increased risk of falling, a 6-month music-based multitask exercise program improved gait under dual-task condition, improved balance, and reduced both the rate of falls and the risk of falling. Trial Registration clinicaltrials.gov Identifier: NCT01107288.

The role of exercise in the treatment of osteoporosis

The objective of exercise in the treatment of osteoporosis is to improve axial stability through improvement of muscle strength. Therefore, a back extension exercise program specific to one's musculoskeletal competence and pain can be performed in a sitting position and later advanced to the prone position. When fragility is resolved, back extension is performed against resistance applied to the upper back. To decrease pain and immobility in acute vertebral fracture, use of spinal orthoses become inevitable. Therapeutic exercise should address osteoporosis-related deformities of axial posture, which can increase risk of fall and fracture. Strengthening of the major appendicular muscles decreases fragility. The effect of strengthening exercise is augmented by proper intake of cholecalciferol and calcium. Thus, the role of a therapeutic exercise program is to increase muscle strength safely, decrease immobility-related complications, and prevent fall and fracture. As with pharmacotherapy, therapeutic exercises are individualized.

Decreased bone turnover in children and adolescents with well controlled type 1 diabetes

AIM

Osteoporosis is a common long-term complication of type 1 diabetes (T1DM). We aimed to determine whether bone mineral density (BMD) and turnover are already altered during childhood.

PATIENTS AND METHODS

We recruited 27 T1DM children and 32 controls (age 10.5 +/- 2.5 yr.) and measured BMD (dual-energy x-ray absorptiometry); bone biomarkers levels (osteocalcin: OC; procollagen type 1 propeptides amino-terminal: PINP; crosslinking telopeptides of type 1 collagen C-terminal: CTX), glycated hemoglobin (HbA1c), dietary intake and physical activity.

RESULTS

Patients with T1DM had lower levels of OC (70.3 +/- 3.3 vs 105.3 +/- 6.8), PINP (556.4 +/- 47.6 vs 716.3 +/- 53.8), CTX(0.97 +/- 0.07 vs 1.20 +/- 0.08), physical activity, and calcium intake. Biomarkers were negatively correlated with HbA1c. Though, BMD was similar among groups and not related to HbA1c, disease duration, physical activity or dietary intakes.

CONCLUSIONS

Bone turnover is altered in T1DM children, whereas BMD remains normal during growth. Physical activity and optimal calcium intakes may improve bone metabolism and delay osteoporosis.

Relationship between 3-month changes in biochemical markers of bone remodelling and changes in bone mineral density and fracture incidence in patients treated with strontium ranelate for 3 years

SUMMARY

From two randomised controlled trials, it is shown that 3-month changes in biochemical markers of bone formation (bone-specific alkaline phosphatase and C-terminal propeptide of type I procollagen) were associated with 3-year bone mineral density (BMD) changes, but not fracture incidence in patients treated with strontium ranelate.

INTRODUCTION

The purpose of this study was to assess if short-term change in biochemical markers of bone remodelling is associated with long-term BMD change and fracture incidence observed during treatment with strontium ranelate.

METHODS

From the SOTI and TROPOS trials, bone-specific alkaline phosphatase (BALP), C-terminal propeptide of type I procollagen (PICP), serum C-terminal telopeptides (S-CTX) and urine N-terminal telopeptides of type I collagen (U-NTX) were assessed at baseline and after 3 months.

RESULTS

Two thousand three hundred seventy-three women were included in this study. Multiple regression analysis showed that 3-month changes in PICP and BALP but not s-CTX I nor s-NTX I were significantly (p < 0.001) associated with 3-year BMD changes at the lumbar spine and the femoral neck. Changes in s-CTX I, PICP and BALP were significantly associated with change in total proximal femur BMD. Changes in biochemical markers explain less than 8% of the BMD changes. The 3-month changes in BALP, PICP s-CTX I and s-NTX I were not significantly associated with fracture incidence.

CONCLUSIONS

Short-term changes in biochemical markers of bone formation are associated with future BMD changes in patients treated with strontium ranelate, suggesting a bone-forming activity of this treatment, but are not appropriate to monitor the efficacy of strontium ranelate at the individual level.