Bone turnover and the response to alendronate treatment in postmenopausal osteoporosis

Changes in Testing and Treatment Methods in Osteoporosis Care

Osteoporosis treatment plays a crucial role in preventing fractures, particularly in bedridden patients. We conducted a questionnaire survey presenting hypothetical clinical cases in 2015 and 2020 to investigate trends over a 5-year period. The target population included physicians working in clinics and hospitals within our neighbourhood. The cases were presented, and the questionnaire was administered in a confidential format. The orthopaedic surgeons were matched for age and practice, resulting in 74 cases being included in the analysis. Comparing the 2015 and 2020 results, we observed a notable increase in physicians who would perform "bone mineral density measurements of the lumbar spine and hip." Furthermore, there was a significant rise in the percentage of respondents willing to test for bone metabolic markers, such as serum type I collagen cross-linked N-telopeptide (NTX), procollagen I N-terminal propeptide (P1NP), and tartrate-resistant acid phosphatase 5b (TRACP-5b). Regarding therapeutic agents, bisphosphonates decreased in usage, whereas parathyroid hormone and romosozumab witnessed an increase. In conclusion, the percentage of physicians requesting bone mineral density measurements of the lumbar spine and hip increased over the five-year period. In addition, more physicians chose to utilise bone metabolic markers due to their ease of measurement through blood tests and reduced diurnal variation. Finally, there was a marked trend towards the administration of drugs capable of rapidly and effectively increasing bone mineral density at an early stage of treatment.

Pre-treatment bone turnover does not influence the level of the response to alendronate in postmenopausal osteoporosis at the bone tissue level

PURPOSE

The main effect of anti-resorptive agents such as bisphosphonates is a reduction of bone resorption, with a consequent marked decrease of bone turnover. This post-hoc analysis investigated the changes of histomorphometric parameters of bone turnover after alendronate (ALN), according to the baseline turnover.

METHODS

Ninety postmenopausal women underwent a transiliac bone biopsy before and after 6 (n = 44) or 12 (n = 46) months of treatment with ALN (70 mg/week). The dynamic parameters reflecting the bone formation and bone turnover were mineralizing surface (MS/BS; %), bone formation rate (BFR/BS; μm3/μm2/d), and activation frequency (Ac.f; /yr). Biochemical markers sPINP and the sCTX were assessed before treatment and after 3, 6, and 12 months. Subjects were divided into quartiles based on the baseline values of BFR/BS.

RESULTS

At baseline, MS/BS and Ac.f were significantly different (p < 0.0001) among the BFR quartiles. sCTX and sP1NP were not significantly different among quartiles. After ALN treatment, MS/BS was not significantly different among quartiles but Ac.f remained significantly lower in the first quartile compared to the third and fourth ones (p < 0.03). The absolute value of the difference between pre- and post-treatment significantly correlated with the baseline BFR/BS but when expressed in percent of the baseline value, the magnitude of the diminutions of MS/BS, Ac.f, sCTX, and sP1NP was similar in the four baseline BFR quartiles.

CONCLUSION

The percentage response to ALN appeared independent of the baseline level of bone turnover. After treatment, the bone turnover tended to be similar in all BFR quartiles. This analysis investigated the influence of baseline turnover measured by bone histomorphometry on the effect of alendronate. When expressed in percent of pre-treatment values, the decreases of histomorphometric parameters and biochemical markers of bone turnover were independent of the baseline turnover.

Zoledronic acid sequential to teriparatide may promote greater inhibition of bone resorption than zoledronic acid alone

Background

Teriparatide (TPTD) should be followed by an antiresorptive to maximize bone mineral density gain and anti-fracture protection. Infrequent zoledronic acid (ZOL) administration has demonstrated effectiveness. The duration of ZOL effect following TPTD is unknown.

Objective

To evaluate the effect of ZOL on bone resorption marker in a post-TPTD versus ZOL-alone scenario in osteoporotic patients.

Design

Retrospective cohort study.

Methods

Patients treated with TPTD followed by ZOL (TPTD-ZOL) or with a single ZOL infusion were identified in the database of a tertiary referral center. Clinical and laboratory data, including C-terminal telopeptide of type I collagen (CTX) following ZOL treatment, were compared.

Results

Twenty-six patients (93% women) treated with TPTD-ZOL and 41 with ZOL were comparable in age (median 70.1 versus 69.6 years, p = 0.6) and sex. Timing of CTX measurement post-ZOL was the same, median 1.0 year. CTX was lower following TPTD-ZOL (median 142.1 versus 184.2 pg/mL, p = 0.005). In a multivariable regression model (controlled for baseline characteristics), pretreatment with TPTD strongly predicted CTX <150 pg/mL, 1 year following ZOL (odds ratio = 7.5, 95% CI 1.3-58.1, p = 0.03). In a subgroup with sequential CTX measurements following one ZOL, significantly lower levels persisted in the TPTD-ZOL group for a median of 4.4 years follow-up.

Conclusion

ZOL-administered sequential to TPTD yielded deeper and more prolonged bone resorption suppression than ZOL alone. Prospective data are needed to confirm whether in a sequential treatment scenario, subsequent ZOL dosing interval should be less frequent.

Bone Turnover Markers for Assessment of Anti-Resorptive Effect in Clinical Practice: A Good Idea Meets the Problem of Measurement Uncertainty

OBJECTIVES

Bone turnover markers (BTM) are measures for understanding the effect of anti-resorptives upon osteoclast activity. Post-hoc trial data suggests reduction in BTM of 40% may represent a target for defining appropriate response to therapy. We modeled clinical application of this target threshold in an individual patient setting where assay measurement uncertainty and biological variation are included.

DESIGN

Using serum C-telo-peptide (ß-CTX), we constructed hypothetical scenarios of ß-CTX measurement pre and post bisphosphonate therapy. Using typical ß-CTX assay characteristics (analytical coefficient of variation, CV 5.0%) and published intra-individual ß-CTX data for post-menopausal women (CV 18.0%), we calculated the post-therapy ß-CTX that must be seen on single repeat measure for 95% confidence that the observed result was ≥40% below baseline. Sensitivity analyses considered greater and lesser variations in the combined sources of variation.

RESULTS

The one-tailed 95% reference change value for any detectable therapeutic decrease in ß-CTX was 22%. However, to have 95% confidence of having achieved a reduction ≥ 40%, an observed ß-CTX decrease of ≥56% is required. Larger decreases are needed for scenarios of greater analytical or intra-individual variation.

CONCLUSIONS

Although population data suggest a ß-CTX decrease of 40% is commensurate with adequate therapeutic response to anti-resorptives, application to an individual patient where measurement and natural variation are present is problematic. ß-CTX decreases much greater than 40% are required to be confident of having achieved the optimal treatment response. It is uncertain whether this is a legitimate change to be expected in all individual patients and therefore clinical application of this threshold is uncertain.

Denosumab treatment is associated with decreased cortical porosity and increased bone density and strength at the proximal humerus of ovariectomized cynomolgus monkeys

Upper extremity fractures, including those at the humerus, are common among women with postmenopausal osteoporosis. Denosumab was shown to reduce humeral fractures in this population; however, no clinical or preclinical studies have quantified the effects of denosumab on humerus bone mineral density or bone microarchitecture changes. This study used micro-computed tomography (μCT) and computed tomography (CT), alongside image-based finite element (FE) models derived from both modalities, to quantify the effects of denosomab (DMAb) and alendronate (ALN) on humeral bone from acutely ovariectomized (OVX) cynomolgus monkeys. Animals were treated with 12 monthly injections of s.c. vehicle (VEH; n = 10), s.c. denosumab (DMAb; 25 mg/kg, n = 9), or i.v. alendronate (ALN; 50 μg/kg, n = 10). Two more groups received 6 months of VEH followed by 6 months of DMAb (VEH-DMAb; n = 7) or 6 months of ALN followed by 6 months of DMAb (ALN-DMAb; n = 9). After treatment, humeri were harvested and μCT was used to quantify tissue mineral density, trabecular morphology, and cortical porosity at the humeral head. Clinical CT imaging was also used to quantify trabecular and cortical bone mineral density (BMD) at the ultra-proximal, proximal, 1/5 proximal and midshaft of the bone. Finally, μCT-based FE models in compression, and CT-based FE models in compression, torsion, and bending, were developed to estimate differences in strength. Compared to VEH, groups that received DMAb at any time demonstrated lower cortical porosity and/or higher tissue mineral density via μCT; no effects on trabecular morphology were observed. FE estimated strength based on μCT was higher after 12-months DMAb (p = 0.020) and ALN-DMAb (p = 0.024) vs. VEH; respectively, FE predicted mean (SD) strength was 4649.88 (710.58) N, and 4621.10 (1050.16) N vs. 3309.4 (876.09) N. All antiresorptive treatments were associated with higher cortical BMD via CT at the 1/5 proximal and midshaft of the humerus; however, no differences in CT-based FE predicted strength were observed. Overall, these results help to explain the observed reductions in humeral fracture rate following DMAb treatment in women with postmenopausal osteoporosis.

Diabetes and Osteoporosis: Part II, Clinical Management

Diabetes-induced osteoporosis is characterized by an increase in fracture risk. FRAX, the most widely used tool, underestimates the risk of fracture in both type 1 and type 2 diabetes. Specific adjustments to FRAX can help to better identify patients with diabetes at increased risk of fracture and select those at high fracture risk for treatment. Although clinical trial data are limited, the available evidence indicates that the presence of diabetes does not alter antiosteoporotic treatment response in patients with diabetes.

Comparative Effect of Zoledronate at 6 Versus 18 Months Following Denosumab Discontinuation

Discontinuation of denosumab treatment is associated with rapid bone loss that could be prevented in many patients by zoledronate (ZOL) infusion given 6 months after the last denosumab injection. The effects, however, of zoledronate administration at a later time point are unknown. We aimed to compare the 1-year effect of ZOL infusion given 6 versus 18 months following the last Dmab injection. In this extension of a previously reported 2-year randomized clinical trial, we included initially treatment-naive postmenopausal women, who became osteopenic after approximately 2.5 years of denosumab therapy, and were subjected to a single ZOL infusion at 6 months (early-ZOL, n = 27) versus 18 months (late-ZOL, n = 15) after the last Dmab injection. Annual changes in lumbar spine (LS) and femoral neck (FN) bone mineral density (BMD), and markers of bone turnover (P1NP, CTx) at 6 and 12 months following ZOL infusion were assessed. LS BMD was maintained in both early-ZOL (+ 1.7%) and late-ZOL (+ 1.8%) infusion with no difference between groups (p = 0.949). FN BMD was maintained in early-ZOL (+ 0.1%) and increased in late-ZOL (+ 3.4%) infusion with no difference between groups (p = 0.182). Compared to 6 months after last Dmab injection, the overall LS BMD change of the late-ZOL group (- 3.5%) was significantly different (p = 0.007) from that of the early-ZOL group (+ 1.7%). P1NP and CTx gradually increased in the early-ZOL group, while profoundly decreased and remained suppressed in the late-ZOL infusion. A ZOL infusion 18 months following the last Dmab injection is still useful in terms of BMD maintenance and BTM suppression. However, there is no clear clinical benefit compared to the early infusion, while any theoretical advantage is counterbalanced from the expected bone loss, especially at the LS, and the risk of rebound-associated fractures.Trial Registration: NCT02499237; July 16, 2015.

Probiotic supplements and bone health in postmenopausal women: a meta-analysis of randomised controlled trials

OBJECTIVE

Osteoporosis is a common disease in postmenopausal women. Several studies have analysed the associations between dietary supplementation with probiotics and bone health in postmenopausal women, but the results are still controversial. We conducted this meta-analysis to assess the effects of probiotics supplement on bone mineral density (BMD) and bone turnover markers for postmenopausal women.

DESIGN

Systematic review and meta-analysis.

METHODS

We systematically searched PubMed, EMBASE and the Cochrane Library from their inception to November 2020 for randomised controlled trials (RCTs) assessing probiotic supplements and osteoporosis in postmenopausal women. Study-specific risk estimates were combined using random-effect models.

RESULTS

Five RCTs (n=497) were included. Probiotic supplements were associated with a significantly higher BMD in the lumbar spine (standardised mean difference, SMD=0.27, 95% CI 0.09 to 0.44) than in control. There was no difference between probiotic supplements and BMD in hips (SMD=0.22, 95% CI -0.07 to 0.52). Collagen type 1 cross-linked C-telopeptide levels in the treatment groups were significantly lower than those of the placebo group (SMD=-0.34, 95% CI -0.60 to -0.09). In subgroup meta-analysis, levels of bone-specific alkaline phosphatase, osteoprotegerin, osteocalcin and tumour necrosis factor did not differ between the probiotic and placebo groups.

CONCLUSIONS

We conclude cautiously that supplementation with probiotics could increase lumbar BMD. More RCTs are recommended to validate or update these results.

Effects of denosumab on rheumatic diseases and refractory glucocorticoid-induced osteoporosis: a prospective study

This study evaluates the clinical efficacy of denosumab for glucocorticoid-induced osteoporosis (GIOP) refractory to previous osteoporosis treatment. Our results show that denosumab significantly increased BMD of the lumbar spine and bilateral hip over the 24-month study period. Denosumab demonstrates potential as a treatment for GIOP refractory to previous therapy.

INTRODUCTION

The aim of this study was to evaluate the clinical efficacy and safety of denosumab in patients with rheumatic diseases and glucocorticoid-induced osteoporosis (GIOP) refractory to previous osteoporosis treatment.

METHODS

All patients were treated with 60 mg of denosumab subcutaneously every 6 months for 2 years after administration of bisphosphonates or rhPTH was stopped. We assessed bone mineral density (BMD) of the lumbar spine and bilateral hip at baseline, and at 6, 12, 18, and 24 months. We measured serum levels of bone alkaline acid phosphatase (BAP) and tartrate-resistant acid phosphatase (TRACP)-5b at baseline, and at 3, 6, 12, 18, and 24 months.

RESULTS

Fifty-five patients with rheumatic diseases and GIOP were enrolled in this study. All patients were treated with bisphosphonates (n=40), recombinant human parathyroid hormone (n=4), or active vitamin D₃ (n=11). Over the 24-month study period, denosumab significantly increased the mean BMD of the lumbar spine and bilateral hip (5.8 ± 0.7%, and 1.3 ± 0.4%, respectively). Additionally, denosumab also significantly reduced the serum levels of TRACP-5b and BAP over this same period (by -38.8 ± 3.5% and -16.3 ± 3.1%, respectively), although these changes in bone turnover markers were not predictive factors of an improvement in BMD values. While three patients developed fragility fractures during the study period, all three had several risk factors for fragility fractures in GIOP.

CONCLUSIONS

In conclusion, denosumab is a potential treatment for GIOP in rheumatic diseases, especially in patients refractory to previous therapy, including bisphosphonate therapy.

Zoledronate for the Prevention of Bone Loss in Women Discontinuing Denosumab Treatment. A Prospective 2-Year Clinical Trial

Cessation of denosumab treatment is associated with increases in bone turnover above baseline values and rapid bone loss. We investigated the efficacy of zoledronate to prevent this bone loss in women with postmenopausal osteoporosis who were treated with denosumab (mean duration 2.2 years) and discontinued treatment after achieving osteopenia. Women were randomized to receive a single 5-mg infusion of zoledronate (ZOL) (n = 27) or two additional 60-mg injections of denosumab (Dmab) (n = 30). Both groups were followed for a total period of 24 months. At 24 months lumbar spine-bone mineral density (LS-BMD) was not different from baseline in the ZOL group, but decreased in the Dmab group by (mean ± SD) 4.82% ± 0.7% (p < 0.001) from the 12-month value; the difference in BMD changes between the two groups, the primary endpoint of the study, was statistically significant (p = 0.025). Results of femoral neck (FN)-BMD changes were similar. ZOL infusion was followed by small but significant increases in serum procollagen type 1 N-terminal propeptide (P1NP) and C-terminal telopeptide of type 1 collagen (CTX) during the first year and stabilization thereafter. In the Dmab group, bone turnover marker values did not change during the first 12 months but increased significantly at 15 months and in the majority of women these remained elevated at 24 months. Neither baseline nor 12-month bone turnover marker values were associated with BMD changes in either group of women. In the Dmab group, three patients sustained vertebral fractures (two patients multiple clinical, one patient morphometric) whereas one patient in the ZOL group sustained clinical vertebral fractures 12 months after the infusion. In conclusion, a single intravenous infusion of ZOL given 6 months after the last Dmab injection prevents bone loss for at least 2 years independently of the rate of bone turnover. Follow-up is recommended, because in a few patients ZOL treatment might not have the expected effect at 2 years. © 2019 American Society for Bone and Mineral Research.

Diabetes and Bone Disease

The World Health Organization estimates that diabetes mellitus occurs in more than 415 million people; this number could double by the year 2040. Epidemiologic data have shown that the skeletal system may be a target of diabetes-mediated damage, leading to the development of diabetes-induced osteoporosis. T1D and T2D have been associated with an increased risk of fracture. Bone mineral density and fracture risk prediction tools developed for the general population capture some of the risk associated with diabetes. Recent adaptations to these tools have improved their efficacy in patients with diabetes.

Commentary: Concurrent administration of PTH and antiresorptives: Additive effects or DXA cosmetics

Osteoanabolic therapy with parathyroid hormone (PTH(1-84)) or the PTH analogues teriparatide (PTH(1-34), TPTD) and abaloparatide induces a positive remodeling balance and increases modeling and remodeling activity on bone surfaces. As the anabolic action of PTH is primarily remodeling based increased bone turnover maximizes bone accrual. Increased remodeling, however, also increases cortical porosity and reduces mineralization of newly formed bone, which may cause initial reductions in BMD, particularly at sites rich in cortical bone. Increased cortical porosity may also have negative consequences for bone strength. Consequently, an interest developed in concurrent therapies offsetting the potential early negative cortical bone effects developed, and several studies using varying concurrent combinations of TPTD or PTH(1-84) with various antiresorptive (anti-catabolic) agents (estrogen, SERMs, bisphosphonates and denosumab) have been published. This commentary addresses the discrepancy between changes in areal bone mineral density (BMD) and bone turnover markers (BTM) in concurrent therapy studies leading to possible misinterpretations of the results. In studies of concurrent therapies increases in BMD are generally accompanied by decreases in biochemical markers of bone turnover. This includes Procollagen Type I N-Terminal Propetide (PINP), which has emerged as a reliable marker of bone formation during osteoanabolic therapy. We therefore want to submit, that the larger increases in BMD seen initially in patients on concurrent therapy mask the potential for later reduced osteoanabolic action of PTH. This notion is corroborated by: 1) the lesser impairment of bone anabolism seen with milder antiresorptive modalities like hormone replacement therapy (HRT) or Selective Estrogen Receptor Modulators (SERMs); 2) the changes in BMD seen in extension studies where treatment naïve patients previously treated with PTH alone are crossed over to antiresorptive drugs. We therefore advise against a general use of concurrent therapy with PTH and antiresorptive agents, as it entails blunting of osteoanabolic action of PTH in the long run.

Vitamin D, osteoprotegerin/receptor activator of nuclear factor-kappaB ligand (OPG/RANKL) and inflammation with alendronate treatment in HIV-infected patients with reduced bone mineral density

OBJECTIVES

The aim of the study was to determine the effect of alendronate (ALN) on inflammatory markers and osteoprotegerin (OPG)/receptor activator of nuclear factor-kappaB ligand (RANKL), and to explore the associations of baseline systemic inflammation and vitamin D status on the bone mineral density (BMD) response to ALN.

METHODS

Eighty-two HIV-positive patients with lumbar spine T-score ≤ -1.5 were randomized to ALN 70 mg weekly or placebo for 48 weeks; all received calcium carbonate 500 mg/vitamin D3 200 IU twice daily. Serum C-telopeptide (CTx) and BMD were assessed at baseline and week 48. Stored plasma samples in 70 subjects were assayed for levels of 25-hydroxyvitamin D (25(OH)D), OPG, RANKL, interleukin (IL)-6 and soluble receptors for tumour necrosis factor (TNF)-α 1 and 2 (sTNFR 1 and 2).

RESULTS

ALN increased BMD more than placebo at both the lumbar spine (difference ALN - placebo 2.64%; P = 0.011) and the total hip (difference 2.27%; P = 0.016). No within- or between-arm differences in OPG, RANKL or inflammatory markers were observed over 48 weeks. High baseline CTx and sTNFR2 were associated with a more robust BMD response to ALN over 48 weeks at the lumbar spine [difference 5.66%; 95% confidence interval (CI) 3.50, 7.82; P < 0.0001] and total hip (difference 4.99%; 95% CI 2.40, 7.57; P = 0.0002), respectively. Baseline 25(OH)D < 32 ng/mL was associated with larger increases in total hip BMD over 48 weeks, independent of ALN treatment (P = 0.014).

CONCLUSIONS

Among HIV-positive patients, higher baseline bone resorption and TNF-α activity were associated with an increased BMD response to ALN. The greater BMD response in those with lower vitamin D reinforces the importance of vitamin D supplementation with bisphosphonate treatment.

Zoledronate induces bisphosphonate-related osteonecrosis of the jaw in osteopenic sheep

OBJECTIVES

Bisphosphonate-related osteonecrosis of the jaw (BP-ONJ) occurs in 1 % of patients with medication-induced osteoporosis treated with bisphosphonates. Sheep are an established large animal model for investigating osteoporotic skeletal changes. Zoledronate significantly reduces tissue mineral variability in ovariectomized sheep. The aim of this study was to analyze bone healing after tooth extraction in sheep with induced osteopenia and zoledronate administration.

MATERIALS AND METHODS

Eight adult ewes were randomly divided into two groups of four animals. All sheep underwent ovariectomy and a low-calcium diet. Dexamethasone was administered weekly for 16 weeks. Zoledronate was then given every third week for a further 16 weeks in four sheep; these infusions were repeated after extraction of two lower premolars. Four sheep without zoledronate administrations served as controls.

RESULTS

Due to general health conditions, two sheep of the zoledronate group had to be excluded before surgery. The remaining two sheep of this group developed BP-ONJ lesions at the extraction site and various other sites in both jaws. Control group animals showed uneventful wound healing. Histology of the alveolar processes as well as lumbar spine revealed larger portions of old bone and smaller portions of new bone in the zoledronate group.

CONCLUSIONS

This animal study showed uneventful wound healing after tooth extraction in osteopenic sheep whereas zoledronate treatment leads to development of BP-ONJ-like lesions.

CLINICAL RELEVANCE

As bisphosphonate administration is a standard treatment for glucocorticoid-induced osteoporosis, this model can be used for further research in pathogenesis and management of bisphosphonate-related adverse events.

Peri-implant and systemic effects of high-/low-affinity bisphosphonate-hydroxyapatite composite coatings in a rabbit model with peri-implant high bone turnover

Background

Hydroxyapatite (HA) coatings composed with bisphosphonates (BPs) which have high mineral-binding affinities have been confirmed to successfully enhance implant stability. However, few previous studies focused on HA coatings composed with low-affinity BPs or on systemic effects of locally released BPs.

Methods

In this long-term study, we developed two kinds of BP-HA composite coatings using either high-affinity BP (alendronate, ALN) or low-affinity BP (risedronate, RIS). Thirty-six rabbits were divided into three groups according to different coating applications (group I: HA, group II: ALN-HA, and group III: RIS-HA). Implants were inserted into the proximal region of the medullary cavity of the left tibiay. At insertion, 2 × 10⁸ wear particles were injected around implants to induce a peri-implant high bone turnover environment. Both local (left tibias) and systemic (right tibias and lumbar vertebrae) inhibitory effect on bone resorption were compared, including bone-implant integration, bone architecture, bone mineral density (BMD), implant stability, and serum levels of bone turnover markers.

Results

The results indicated that ALN-HA composite coating, which could induce higher bone-implant contact (BIC) ratio, bone mass augmentation, BMD, and implant stability in the peri-implant region, was more potent on peri-implant bone, while RIS-HA composite coating, which had significant systemic effect, was more potent on non-peri-implant bone, especially lumbar vertebrae.

Conclusions

It is instructive and meaningful to further clinical studies that we could choose different BP-HA composite coatings according to the patient’s condition.

Bone turnover assessment: a good surrogate marker?

To asses fracture risk, bone mineral density (BMD) measured by dual-energy X-ray absorptiometry (DXA) is the most commonly used tool. The search for clinical risk factors is also advised and can provide a 10-year fracture probability (FRAX model). Another important determinant of bone strength is bone remodeling. High bone remodeling rates have been associated with a higher fracture risk and bone turnover markers (BTM) may offer dynamic information about skeletal status independent of BMD. The efficacy of antiresorptive agents in fracture prevention goes beyond what can be predicted by BMD especially in the beginning of the treatment. Inhibition of bone remodeling itself is certainly an important mechanism by which antiresorptive agents can rapidly reduce fracture risk. Thus, it seems quite logical to use BTM in patients with bone disease. It can also become a valuable surrogate marker in fracture prediction. However, BTM's pre-analytical and analytical variability should always be considered.

Vertebral anti-fracture efficacy of strontium ranelate according to pre-treatment bone turnover

Osteoporotic post-menopausal women patients in two randomised trials comparing the anti-fracture efficacy of strontium ranelate with placebo were separated into tertiles according to their baseline levels of biochemical markers of bone formation and resorption. The vertebral anti-fracture efficacy of strontium ranelate was shown to be independent of baseline bone turnover levels.

INTRODUCTION

Bone turnover (BTO) levels vary among women at risk of osteoporotic fracture. Strontium ranelate is an anti-osteoporotic treatment increasing bone formation and reducing bone resorption. It was hypothesised that its anti-fracture efficacy would be independent of baseline BTO levels.

METHODS

Post-menopausal women with osteoporosis from two pooled studies were stratified in tertiles according to baseline levels of two BTO markers: bone-specific alkaline phosphatase (b-ALP, n = 4995) and serum C-telopeptide cross-links (sCTX, n = 4891). Vertebral fracture risk was assessed over 3 years with strontium ranelate 2 g/day or placebo.

RESULTS

In the placebo group, relative risk of vertebral fractures increased with BTO tertiles by 32% and 24% for patients in the highest tertile for b-ALP and CTX, respectively, compared to those in the lowest tertile. In the strontium ranelate group, incidences of vertebral fracture did not differ significantly across BTO tertiles. Significant reductions in vertebral fractures with strontium ranelate were seen in all tertiles of both markers, with relative risk reductions of 31% to 47% relative to placebo. Risk reduction did not differ among tertiles (b-ALP: p = 0.513; sCTX: p = 0.290).

CONCLUSION

The vertebral anti-fracture efficacy of strontium ranelate was independent of baseline BTO levels. Strontium ranelate offers clinical benefits to women across a wide range of metabolic states.

Alendronate treatment results in similar levels of trabecular bone remodeling in the femoral neck and vertebra

SUMMARY

We aimed to determine whether trabecular bone in sites that have different surface-based remodeling rates, the femoral neck and vertebra, are differently affected by alendronate treatment. Alendronate treatment resulted in similar levels of turnover in both sites, suggesting that a lower limit of bone turnover suppression with alendronate may exist.

INTRODUCTION

Bone turnover suppression in sites that already have a low surface-based remodeling rate may lead to oversuppression that could have negative effects on the biomechanical properties of bone. The goal was to determine how alendronate suppresses bone turnover at sites with different surface-based remodeling rates.

METHODS

Dynamic histomorphometric parameters were assessed in trabecular bone of the femoral neck and lumbar vertebrae obtained from skeletally mature beagles treated with saline (1 ml/kg/day) or alendronate (ALN 0.2 or 1.0 mg/kg/day). The ALN0.2 and ALN1.0 doses approximate, on a milligram per kilogram basis, the clinical doses used for the treatment of postmenopausal osteoporosis and Paget's disease, respectively.

RESULTS

Alendronate treatment resulted in similar absolute levels of bone turnover in the femoral neck and vertebrae, although the femoral neck had 33% lower pre-treatment surface-based remodeling rate than the vertebra (p < 0.05). Additionally, the high dose of alendronate (ALN 1.0) suppressed bone turnover to similar absolute levels as the low dose of alendronate (ALN 0.2) in both sites.

CONCLUSIONS

Alendronate treatment may result in a lower limit of trabecular bone turnover suppression, suggesting that sites of low pre-treatment remodeling rate are not more susceptible to oversuppression than those of high pre-treatment remodeling rate.

Biomarkers for osteoporosis management: utility in diagnosis, fracture risk prediction and therapy monitoring

Osteoporosis is a systemic disease characterized by low bone mass and microarchitectural deterioration of bone tissue, resulting in an increased risk of fracture. While the level of bone mass can be estimated by measuring bone mineral density (BMD) using dual X-ray absorptiometry (DXA), its measurement does not capture all the risk factors for fracture. Quantitative changes in skeletal turnover can be assessed easily and non-invasively by the measurement of serum and urinary biochemical markers; the most sensitive markers include serum osteocalcin, bone specific alkaline phosphatase, the N-terminal propeptide of type I collagen for bone formation, and the crosslinked C- (CTX) and N- (NTX) telopeptides of type I collagen for bone resorption. Advances in our knowledge of bone matrix biochemistry, most notably of post-translational modifications in type I collagen, are likely to lead to the development of new biochemical markers that reflect changes in the material property of bone, an important determinant of bone strength. Among those, the measurement of the urinary ratio of native (alpha) to isomerized (beta) CTX - an index of bone matrix maturation - has been shown to be predictive of fracture risk independently of BMD and bone turnover. In postmenopausal osteoporosis, levels of bone resorption markers above the upper limit of the premenopausal range are associated with an increased risk of hip, vertebral, and nonvertebral fracture, independent of BMD. Therefore, the combined use of BMD measurement and biochemical markers is helpful in risk assessment, especially in those women who are not identified as at risk by BMD measurement alone. Levels of bone markers decrease rapidly with antiresorptive therapies, and the levels reached after 3-6 months of therapy have been shown to be more strongly associated with fracture outcome than changes in BMD. Preliminary studies indicate that monitoring changes of bone formation markers could also be useful to monitor anabolic therapies, including intermittent parathyroid hormone administration and, possibly, to improve adherence to treatment. Thus, repeated measurements of bone markers during therapy may help improve the management of osteoporosis in patients.

Administration of pamidronate alters bone-titanium attachment in the presence of endotoxin-coated polyethylene particles

Bisphosphonates are promising in the treatment of periprosthetic osteolysis induced by particulate wear debris. The in vivo effects of pamidronate with different doses and durations of administration on bone-titanium attachment in the presence of endotoxin-coated polyethylene particles were examined in a rat model in this study. Titanium pins and endotoxin-coated polyethylene particles were introduced into rat femoral canals followed by intraperitoneal injection of pamidronate every other day. The treatment varied in the dose from 0 to 40 microg/kg and the duration of either 10 days or 6 weeks. Bilateral femurs were harvested after 6 weeks and examined by bone densitometer and MicroCT scan. Pamidronate increased the bone density of the left, unoperated femurs in a dose and duration dependent manner. Bone-titanium attachment significantly increased in all treatment groups compared to the control group. When pamidronate was administered for 10 days, the increase of bone-titanium attachment was significantly dose-dependent. However, when pamidronate was given for 6 weeks at 4 microg/kg, the bone-titanium attachment was significantly (p < 0.001) lower compared to the 10 day treatment of the same dose, although it was significantly higher than controls. Our results suggest that pamidronate effectively increase bone-titanium attachment even in the presence of endotoxin-coated polyethylene particles. However, long-term administration may reduce its efficacy.

Is a change in bone mineral density a sensitive and specific surrogate of anti-fracture efficacy?

Anti-resorptive agents perturb steady state remodeling; they suppress, but do not abolish, the birth rate of new basic multicellular units (BMUs). In doing so, remodeling goes to completion with bone formation in the many BMUs created before treatment but now with fewer resorption cavities appearing concurrently. As a result, cortical porosity and trabecular stress concentrators decrease reducing bone fragility. From this improved bone strength, steady state is re-established at a slower remodeling rate that again produces bone fragility but more slowly as fewer new BMUs, each with a less negative BMU balance, produce cortical thinning and porosity, trabecular thinning and loss of connectivity while bone fragility progresses rapidly in controls. Thus, the fracture risk reduction--the incidence of fractures in patients treated with an anti-resorptive agent relative to the incidence in controls--is the net effect of the slowing or partial reversal of fragility and then reduced progression of structural abnormalities in treated patients and continued structural decay in controls. Although some morphological features in treated patients and controls may be captured in the bone mineral density (BMD) measurement, many are not. The early increase in BMD is largely determined by the pre-treatment remodeling rate whereas the later and more modest BMD increase is a function of the degree of suppression of remodeling and secondary mineralization. When pre-treatment remodeling rate is low, the increase in BMD is small but the fracture risk reduction (relative to controls with comparable baseline characteristics) is no different to that in patients with high baseline remodeling (relative to their controls) and a greater BMD increase. Therefore, a small increase in BMD does not mean treatment has failed and a large increase in BMD is not indicative of a greater fracture risk reduction.

Clinical application of biochemical markers of bone turnover

With the ageing population in most countries, disorders of bone and mineral metabolism are becoming increasingly relevant to every day clinical practice. Consequently, the interest in, and the need for effective measures to be used in the screening, diagnosis and follow-up of such pathologies have markedly grown. Together with clinical and imaging techniques, biochemical tests play an important role in the assessment and differential diagnosis of metabolic bone disease. In recent years, the isolation and characterisation of cellular and extracellular components of the skeletal matrix have resulted in the development of molecular markers that are considered to reflect either bone formation or bone resorption. These biochemical indices are non-invasive, comparatively inexpensive and, when applied and interpreted correctly, helpful tools in the diagnostic and therapeutic assessment of metabolic bone disease. This review provides an overview of the current evidence regarding the clinical use of biochemical markers of bone remodelling in bone disease, with an emphasis on osteoporosis.

New mechanisms and targets in the treatment of bone fragility

Bone modelling and remodelling are cell-mediated processes responsible for the construction and reconstruction of the skeleton throughout life. These processes are chiefly mediated by locally generated cytokines and growth factors that regulate the differentiation, activation, work and life span of osteoblasts and osteoclasts, the cells that co-ordinate the volumes of bone resorbed and formed. In this way, the material composition and structural design of bone is regulated in accordance with its loading requirements. Abnormalities in this regulatory system compromise the material and structural determinants of bone strength producing bone fragility. Understanding the intercellular control processes that regulate bone modelling and remodelling is essential in planning therapeutic approaches to prevention and treatment of bone fragility. A great deal has been learnt in the last decade. Clinical trials carried out exclusively with drugs that inhibit bone resorption have identified the importance of reducing the rate of bone remodelling and so the progression of bone fragility to achieved fracture reductions of approx. 50%. These trials have also identified limitations that should be placed upon interpretation of bone mineral density changes in relation to treatment. New resorption inhibitors are being developed, based on mechanisms of action that are different from existing drugs. Some of these might offer resorption inhibition without reducing bone formation. More recent research has provided the first effective anabolic therapy for bone reconstruction. Daily injections of PTH (parathyroid hormone)-(1–34) have been shown in preclinical studies and in a large clinical trial to increase bone tissue mass and reduce the risk of fractures. The action of PTH differs from that of the resorption inhibitors, but whether it is more effective in fracture reduction is not known. Understanding the cellular and molecular mechanisms of PTH action, particularly its interactions with other pathways in determining bone formation, is likely to lead to new therapeutic developments. The recent discovery through mouse genetics that PTHrP (PTH-related protein) is a crucial bone-derived paracrine regulator of remodelling offers new and interesting therapeutic targets.

Functional significance of bone density measurements in children with osteogenesis imperfecta

BACKGROUND

The treatment of osteogenesis imperfecta has been directed at improvement of bone mineral density, yet the importance of bone mineral density in predicting functional and clinical outcome in this patient population has not been demonstrated. We used a validated functional outcome measure to identify the relationship between bone mineral density and physical function in children with osteogenesis imperfecta, and we also evaluated the relationship of bone mineral density to the rate of surgery and fracture in patients with osteogenesis imperfecta.

METHODS

Twenty patients (age range, four to seventeen years) with osteogenesis imperfecta who had undergone bone mineral densitometry as measured by dual x-ray absorptiometry of the lumbar spine, wrist, and proximal aspect of the femur between November 1999 and April 2001 were retrospectively analyzed. Functional outcome was measured with use of the Pediatric Outcomes Data Collection Instrument. These questionnaires were completed by the parents of all twenty patients and, in addition, by fifteen patients in the study who were between the ages of eleven and eighteen years. Fracture and surgery rates were calculated on the basis of the number of documented fractures and surgical procedures that the patient had had from the time of the initial presentation until the time of the latest follow-up visit.

RESULTS

There were significant relationships between the bone mineral density of the lumbar spine and the scores obtained on the parent-completed questionnaires with regard to upper-extremity functioning (r = 0.57, p < 0.01), transfers and basic mobility (r = 0.55, p = 0.01), sports and physical functioning (r = 0.55, p = 0.01), and global functioning (r = 0.60, p < 0.004). There were also significant relationships between the bone mineral density of the wrist and the scores obtained on the child-completed questionnaires with regard to upper-extremity functioning (r = 0.82, p < 0.01), sports and physical functioning (r = 0.76, p < 0.01), and global functioning (r = 0.83, p = 0.001). There were significant negative relationships between the bone mineral density of the lumbar spine and the rate of fractures (r = -0.69, p < 0.001) and the bone mineral density of the lumbar spine and the rate of surgery (r = -0.60, p < 0.01).

CONCLUSIONS

There is a relationship between bone mineral density and the functional outcome, rate of fracture, and rate of surgery in patients with osteogenesis imperfecta. Bone mineral density appears to be an indicator of disease severity and may be predictive of long-term functional outcome. To establish specific guidelines for treatment, more data on normative bone-mineral density in children with osteogenesis imperfecta will be needed.

Pretreatment levels of bone turnover and the antifracture efficacy of alendronate: the fracture intervention trial

The influence of pretreatment bone turnover on alendronate efficacy is not known. In the FIT, we examined the effect of pretreatment bone turnover on the antifracture efficacy of daily alendronate given to postmenopausal women. The nonspine fracture efficacy of alendronate was significantly greater among both osteoporotic and nonosteoporotic women with higher baseline levels of the bone formation marker PINP.

INTRODUCTION

Previous trials have shown that high bone turnover is associated with greater increases in BMD among bisphosphonate-treated women. The influence of pretreatment bone turnover levels on antifracture efficacy has not been well studied.

MATERIALS AND METHODS

We randomized women 55-80 years of age with femoral neck BMD T scores < or = -1.6 to alendronate (ALN), 5-10 mg/day (n = 3105), or placebo (PBO; n = 3081). At baseline, 3495 women were osteoporotic (femoral neck BMD T score < or = -2.5 or prevalent vertebral fracture), and 2689 were not osteoporotic (BMD T score > -2.5 and no prevalent vertebral fracture). Pretreatment levels of bone-specific alkaline phosphatase (BSALP), N-terminal propeptide of type 1 collagen (PINP), and C-terminal cross-linked telopeptide of type 1 collagen (sCTx) were measured in all participants using archived serum (20% fasting). The risk of incident spine and nonspine fracture was compared in ALN- and PBO-treated subjects stratified into tertiles of baseline bone marker level.

RESULTS AND CONCLUSIONS

During a mean follow-up of 3.2 years, 492 nonspine and 294 morphometric vertebral fractures were documented. Compared with placebo, the reduction in nonspine fractures with ALN treatment differed significantly among those with low, intermediate, and high pretreatment levels of PINP levels (p = 0.03 for trend). For example, among osteoporotic women in the lowest tertile of pretreatment PINP (<41.6 ng/ml), the ALN versus PBO relative hazard for nonspine fracture was 0.88 (95% CI: 0.65, 1.21) compared with a relative hazard of 0.54 (95% CI: 0.39, 0.74) among those in the highest tertile of PINP (>56.8 ng/ml). Results were similar among women without osteoporosis at baseline. Although they did not reach statistical significance, similar trends were observed with baseline levels of BSALP. Conversely, spine fracture treatment efficacy among osteoporotic women did not differ significantly according to pretreatment marker levels. Spine fracture treatment efficacy among nonosteoporotic women was related to baseline BSALP (p = 0.05 for trend). In summary, alendronate nonspine fracture efficacy is greater among both osteoporotic and nonosteoporotic women with high pretreatment PINP. If confirmed in other studies, these findings suggest that bisphosphonate treatment may be most effective in women with elevated bone turnover.

Who will benefit from antiresorptive treatment (bisphosphonates)?

Bisphosphonates are very effective treatments of postmenopausal osteoporosis. They suppress bone turnover, increase bone mineral density (BMD), and maintain or improve structural and material properties of bone, thereby decreasing the risk of fractures. All patients selected for treatment according to current international guidelines can benefit from bisphosphonate therapy independently of their prevalent rate of bone turnover. Long-term extensions (up to 10 years) of pivotal clinical trials with daily bisphosphonate administration showed sustained efficacy with no evidence of adverse effects on bone metabolism and skeletal fragility. Recent studies focus on the resolution of the effects of bisphosphonates on bone metabolism and fracture risk following cessation of long-term treatment. Such studies may help to formulate treatment recommendations according to the risk of the individual patient.

Prevention and treatment of postmenopausal osteoporosis

Osteoporosis is a systemic disease characterized by low bone mass and microarchitectural deterioration of the skeleton leading to enhanced bone fragility and an increased risk of fracture. Prior to fracture, diagnosis is established by documenting low bone mass. In the first section of this article we review the clinical use of bone mass measurements and biochemical markers of bone remodeling in selecting patients most in need of preventive therapy at menopause. Women with high bone turnover lose bone at menopause more rapidly than those with normal bone turnover and are more likely to derive benefit from the several preventive therapies available. The second section addresses the available technologies used to diagnose osteoporosis and/or establish fragility fracture risk using noninvasive bone mass measurement and biochemical markers of bone remodeling separately or in combination. In the third section we review the several treatment options available for patients with osteoporosis, including alendronate (alendronic acid), risendronate (risedronic acid), calcitonin, teriparatide, and raloxifene, and the approaches to monitoring the therapeutic response. The final section deals with fall protection--an often forgotten aspect of management of the patient at risk for sustaining and osteoporotic fragility fracture.

Relationship between pretreatment bone resorption and vertebral fracture incidence in postmenopausal osteoporotic women treated with risedronate

It is unclear whether the antifracture efficacy of bisphosphonates depends on pretreatment bone turnover. We analyzed the risedronate phase III clinical programs using the urinary excretion of deoxypyridinoline (uDPD) as an index of pretreatment bone resorption rates. Risedronate reduced incident vertebral fractures in women with postmenopausal osteoporosis independent from pretreatment bone resorption.

INTRODUCTION

Earlier studies on postmenopausal osteoporosis have suggested that the therapeutic efficacy of antiresorptive therapies might be influenced by pretreatment bone turnover. Because all of these studies have used bone mineral density (BMD) as the primary endpoint, it remains unclear whether this association holds true for incident fractures.

MATERIALS AND METHODS

This study aims to answer this question in a post hoc analysis of a subset of the risedronate phase III clinical programs, using the urinary excretion of deoxypyridinoline (uDPD) as an index of pretreatment bone resorption (PBR). A total of 1593 women with postmenopausal osteoporosis that had baseline uDPD values and paired spinal radiographs available were pooled, in similar proportions, from the risedronate multinational and North American VERT, and from the risedronate HIP trials. Patients from treatment and placebo groups were stratified by the uDPD premenopausal normative median. The four resulting groups were balanced for age, years since menopause, body mass index, baseline femoral neck BMD, and number of prevalent fractures, but baseline lumbar spine BMD was significantly higher in patients with low PBR rates.

RESULTS

In all groups, the proportion of patients with new vertebral fractures was higher in patients with baseline uDPD levels above the normative median. The incidence of vertebral fracture was significantly lower in groups assigned to risedronate compared with placebo. This effect was independent of PBR: in patients with high PBR, the relative risk (RR) of vertebral fracture after 1 year of risedronate was 0.28 (p = 0.03 compared with controls, absolute risk reduction 7.1%). In patients with low PBR, the RR of fracture after 1 year was 0.33 (p < 0.001, absolute risk reduction 4%). After 3 years, the RR of fracture was 0.52 (p = 0.042, absolute risk reduction 8.3%) in patients with high PBR, and 0.54 (p = 0.002, absolute risk reduction 7.1%) in patients with low PBR. Results were similar after adjusting for age, baseline lumbar spine BMD, and prevalent fractures. The number needed to treat to avoid one vertebral fracture at 12 months was 15 in the group of patients with high PBR and 25 in patients with low PBR. Risedronate significantly increased lumbar spine BMD. During the first year of treatment, women with high PBR gained lumbar spine BMD at a faster rate than patients with low PBR. Treatment-by-PBR status interactions were not significantly different over time.

CONCLUSION

The efficacy of risedronate to reduce incident vertebral fractures in women with postmenopausal osteoporosis is largely independent of pretreatment bone resorption rates.

Osteoporosis: Point-of-Care Testing

OBJECTIVE

To review the literature concerning the utility of point-of-care (POC) testing devices for the diagnosis and management of osteoporosis.

DATA SOURCES

Articles were identified from a MEDLINE search (1993–June 2003). Additional references were obtained from cross-referencing the bibliographies of selected articles.

STUDY SELECTION AND DATA EXTRACTION

After evaluation of clinical trials and select review articles, articles comparing peripheral dual-energy absorptiometry (pDXA) or quantitative ultrasound (QUS) with central DXA (cDXA) measurements were emphasized in this analysis.

DATA SYNTHESIS

Sensitivity for detecting osteoporosis by QUS or pDXA varies widely (range 35–75%). Using adjusted T-score cutoffs increases sensitivity to 85–95%, at the price of reducing device specificity to 23–49%. Many states require a radiology technician to perform pDXA tests.

CONCLUSIONS

POC testing with peripheral devices should only be considered in areas with limited access to cDXA or for women who initially refuse cDXA testing. T scores of −1.0 or less with POC testing typically require further evaluation via cDXA. Many states require pDXAs to be performed by certified radiology technologists, making QUS use more feasible for pharmacists. POC testing should not be used for assessing response to osteoporosis therapy.

Biochemical markers of bone remodeling

Because of the aging population in most countries, disorders of bone and mineral metabolism are becoming increasingly relevant to everyday clinical practice. Consequently, the interest in, and the need for effective measures to be used in the screening, diagnosis, and follow-up of such pathologies has markedly grown. Together with clinical and imaging techniques, laboratory tests play an important role in the assessment and differential diagnosis of metabolic bone disease.

Effects of oral alendronate in elderly patients with osteoporosis and mild primary hyperparathyroidism

In a large proportion of the patients with primary hyperparathyroidism (PHPT), a variable degree of osteopenia is the only relevant manifestation of the disease. Low bone mineral density (BMD) in patients with PHPT is an indication for surgical intervention because successful parathyroidectomy results in a dramatic increase in BMD. However, low BMD values are almost an invariable finding in elderly women with PHPT, who are often either unwilling or considered unfit for surgery. Bisphosphonates are capable of suppressing parathyroid hormone (PTH)-mediated bone resorption and are useful for the prevention and treatment of postmenopausal osteoporosis. In this pilot-controlled study, we investigated the effects of oral treatment with alendronate on BMD and biochemical markers of calcium and bone metabolism in elderly women presenting osteoporosis and mild PHPT. Twenty-six elderly patients aged 67-81 years were randomized for treatment with either oral 10 mg alendronate on alternate-day treatment or no treatment for 2 years. In the control untreated patients a slight significant decrease was observed for total body and femoral neck BMD, without significant changes in biochemical markers of calcium and bone metabolism during the 2 years of observation. Urine deoxypyridinoline (Dpyr) excretion significantly fell within the first month of treatment with alendronate, while serum markers of bone formation alkaline phosphatase and osteocalcin fell more gradually and the decrease became significant only after 3 months of treatment; thereafter all bone turnover markers remained consistently suppressed during alendronate treatment. After 2 years in this group we observed statistically significant increases in BMD at lumbar spine, total hip, and total body (+8.6 +/- 3.0%, +4.8 +/- 3.9%, and +1.2 +/- 1.4% changes vs. baseline mean +/- SD) versus both baseline and control patients. Serum calcium, serum phosphate, and urinary calcium excretion significantly decreased during the first 3-6 months but rose back to the baseline values afterward. Increase in serum PTH level was statistically significant during the first year of treatment. These preliminary results may make alendronate a candidate as a supportive therapy in patients with mild PHPT who are unwilling or are unsuitable for surgery, and for whom osteoporosis is a reason of concern.

Bone turnover markers and estradiol level in postmenopausal women

It has been found recently that women with estradiol (E) levels < 5 pg/ml were more likely to suffer osteoporotic fractures. We evaluated the relationships between biomarkers of bone turnover and changes in hormone levels in early or late postmenopausal women without any replacement therapy. Follicle stimulating hormone (FSH), luteinizing hormones (LH), estradiol and serum resorption (crosslaps) and formation (osteocalcin) markers were assayed. Bone densities in the spine and femoral neck were also measured. Elevated FSH, LH and decreased estradiol in postmenopausal women were accompanied by higher osteocalcin (9.1-9.7 ng/ml) and crosslaps level (3305-3458 pmol/l) compared to premenopausal women (6.8 ng/ml and 2087 pmol/l). Bone density was lower in elderly women. A significant inverse correlation was found between estradiol and crosslaps level; FSH and LH were also correlated with bone markers. Estradiol levels < 9 pg/ml were associated with increased bone resorption, decreased hip bone density and higher frequency of osteopenia and osteoporosis. Over 57% of women with an estradiol < 9 pg/ml could be identified as having "a high turnover" compared with 30% with estradiol above 9 pg/ml. Our results indicate that changes in bone density may not be very clear but an increase in bone turnover is distinctly apparent in women with severe estradiol deficiency.