Salmon calcitonin reduces vertebral fracture rate in postmenopausal crush fracture syndrome

Molecular-Based Treatment Strategies for Osteoporosis: A Literature Review

Osteoporosis is an unavoidable public health problem in an aging or aged society. Anti-resorptive agents (calcitonin, estrogen, and selective estrogen-receptor modulators, bisphosphonates, anti-receptor activator of nuclear factor κB ligand antibody along with calcium and vitamin D supplementations) and anabolic agents (parathyroid hormone and related peptide analogs, sclerostin inhibitors) have major roles in current treatment regimens and are used alone or in combination based on the pathological condition. Recent advancements in the molecular understanding of bone metabolism and in bioengineering will open the door to future treatment paradigms for osteoporosis, including antibody agents, stem cells, and gene therapies. This review provides an overview of the molecular mechanisms, clinical evidence, and potential adverse effects of drugs that are currently used or under development for the treatment of osteoporosis to aid clinicians in deciding how to select the best treatment option.

Calcitonin: a drug of the past or for the future? Physiologic inhibition of bone resorption while sustaining osteoclast numbers improves bone quality

Postmenopausal osteoporosis results from a continuous imbalance between bone resorption and bone formation, favoring bone resorption. An increasing number of treatments for osteoporosis are in development and on the market. A range of differences and similarities are found between these treatment options, and these need to be carefully evaluated before the initiation of treatment. This article summarizes data from in vitro and animal studies, as well as clinical trials, on the effect of calcitonin on bone turnover. Calcitonin was found to exert its antiresorptive effects via directly reducing osteoclastic resorption, and thus leads to an increase in bone mineral density and bone strength. Furthermore, calcitonin appears to mainly target the most active osteoclasts, and in contrast to most other antiresorptive agents it does not reduce the number of osteoclasts. Finally, in humans, while attenuating resorption, calcitonin treatment does not interfere markedly with bone formation, in contrast to other currently available antiresorptive agents. Thus, we speculate that calcitonin treatment will lead to a continuously positive bone balance in contrast with other antiresorptive agents currently on the market and thereby, in a physiologic manner, result in improved bone quality. Calcitonin is currently only available in injectable and nasal formulations. An oral formulation may, however, improve patient acceptance and compliance. Currently, several different routes are being pursued to identify an optimal oral formulation, of which the technology based on 5-CNAC is the most advanced. There are promising clinical data available for this formulation from both osteoarthritis and osteoporosis clinical trials, although the antifracture efficacy is not yet known.

Salmon calcitonin: a review of current and future therapeutic indications

Salmon calcitonin, available as a therapeutic agent for more than 30 years, demonstrates clinical utility in the treatment of such metabolic bone diseases as osteoporosis and Paget's disease, and potentially in the treatment of osteoarthritis. This review considers the physiology and pharmacology of salmon calcitonin, the evidence based research demonstrating efficacy and safety of this medication in postmenopausal osteoporosis with potentially an effect on bone quality to explain its abilities to reduce the risk of spine fracture, the development of an oral salmon calcitonin preparation, and the therapeutic rationale for this preparation's chondroprotective effect in osteoarthritis.

The effects of bone therapy on tibial bone loss in young women with anorexia nervosa

OBJECTIVE

Osteoporosis is recognized as a common medical complication of anorexia nervosa (AN). The purpose of the current study was to investigate the recovery mechanism of osteoporosis in AN and the effect of medical treatment on the skeletal system.

METHOD

We conducted a randomized placebo-controlled study of the effects of etidronate and calcium and vitamin D on bone loss in 41 outpatients with the restricting type of AN (AN-R). We measured the tibial speed of sound (SOS) before and after 3 months of treatment.

RESULTS

The bone mineral density (BMD) of the tibial SOS change in both the etidronate group and the calcium and vitamin D Group was significantly greater (p < .001) than in the control group. Urine-N-telopeptide cross-links of type I collagen (NTx) before and after treatment decreased significantly (p < .01) in the etidronate group.

CONCLUSION

These findings suggest that both etidronate and calcium and vitamin D are equally efficacious for reversing the degree of osteoporosis in patients with AN.

Calcitonin: physiological actions and clinical applications

Calcitonin (CT) was first reported as a hypocalcemic principle, initially thought to originate from the parathyroid gland, a view subsequently corrected to an origin from parafollicular C-cells. Human CT is a 32 amino acid peptide with an N-terminal disulphide bridge and a C-terminal prolineamide residue, shown to potently inhibit bone resorption. More recent studies have demonstrated that this may take place through a direct osteoclastic action. A number of osteoclast CT receptors have subsequently been characterized and particular receptor regions necessary for ligand binding and intracellular signaling identified. Its potent anti-resorptive effect has led to its use in treating Paget's bone disease, osteoporosis, hypercalcaemia and osteogenesis imperfecta. This review summarises some key aspects of its synthesis, structure and its actions at the cellular and molecular levels, and leads on to its therapeutic uses that have emerged since its discovery as well as possibilities for future clinical applications.

Acute and long-term management of patients with vertebral fractures

Symptomatic vertebral fractures are associated with significant morbidity, excess mortality and health and social service expenditure. Up to 20% of patients with an incident vertebral fracture experience a further vertebral fracture within one year. It is therefore important that vertebral fractures are detected early, and treatment considered as soon as possible. Only a third of vertebral fractures come to medical attention, where they typically present with acute back pain, but other presentations include loss of height and increasing kyphosis. Spine X-rays should then be performed to confirm the diagnosis and exclude other pathology. Bone density measurements are not essential before starting treatment for osteoporosis in patients with low-trauma vertebral fractures, but may be useful to confirm osteoporosis when there is uncertainty about previous trauma. They may also aid in selecting the most appropriate therapy and monitoring response to treatment. Up to 30% of women and 55% of men with symptomatic vertebral crush fractures have underlying secondary osteoporosis, where treatment may lead to large increases in bone density. These conditions should therefore be sought by medical history, physical examination and appropriate investigations. The management of patients with acute vertebral fractures should include measures to reduce pain and improve mobility, as well as starting treatment for osteoporosis. Treatments have now been shown in randomized controlled trials to improve bone density and reduce the incidence of vertebral and non-vertebral fractures in patients with osteoporosis. Choice of treatment will depend on the underlying causes of bone loss, efficacy in any particular situation, cost, patient preference and the potential non-skeletal advantages and disadvantages.

Effect of menatetrenone (vitamin K2) treatment on bone loss in patients with anorexia nervosa

Osteoporosis is a common complication of anorexia nervosa (AN). Although weight recovery and resumption of menses are important goals in AN treatment, they are often achieved only after a prolonged period of recovery. Therefore, it becomes important to find therapies with the potential to prevent further decreases in bone mineral density (BMD). We conducted a non-randomized study of the effects of menatetrenone (vitamin K2) on bone loss in patients with AN. Lumbar BMD was longitudinally measured by Dual Energy X-ray Absorptiometry (DXA) in 10 patients with AN who chose to receive menatetrenone treatment (MED+ group) and 11 patients who did not (MED- group). During the mean 0.9-year follow-up period, the BMD of the lumbar vertebrae of the MED+ group decreased significantly less than that of the MED- group (-2.8% and -6.9%, respectively). Among bone metabolism markers, gamma-carboxyglutamic acid osteocalcin significantly increased (128.6% and 28.3%, respectively) and urine deoxypyridinoline significantly decreased (-44.5% and -13.7%, respectively) more in the MED+ group than in the MED- group. These differences in BMD and bone metabolism markers may be attributable to menatetrenone treatment. The results suggest that menatetrenone may be beneficial in the prevention of bone loss in patients with AN. Randomized placebo-controlled studies are needed to confirm these findings.

Osteoporosis

Osteoporosis is characterised by low bone mass and microarchitectural deterioration of bone tissue, leading to enhanced bone fragility and consequent increase in fracture risk. It is a common condition affecting one in three women and one in 12 men, resulting in substantial morbidity, excess mortality, and health and social services expenditure. It is therefore important to develop strategies to prevent and treat osteoporosis in both men and women. This paper reviews the pathogenesis of primary and secondary osteoporosis, as well as diagnosis, investigation, and management. This should include lifestyle changes to reduce bone loss and decrease the risk of falls, the identification and treatment of secondary causes of bone loss, and specific treatment for osteoporosis. Hormone replacement therapy, raloxifene, bisphosphonates, calcium and vitamin D, calcitonin, and parathyroid hormone have all been shown to improve bone density and decrease the risk of fracture in specific situations. It is important that treatment is tailored to the individual patient, to ensure compliance and optimise the potential benefits.

Calcitonin: the other thyroid hormone

Calcitonin was originally discovered as a hypocalcemic factor synthesized by thyroid parafollicular C cells. Early experiments demonstrated that calcitonin inhibited bone resorption and decreased calcium efflux from isolated cat tibiae and subsequent histologic and culture studies confirmed the osteoclast as its major site of action. Its potent antiresorptive effect and analgesic action have led to its clinical use in treatment of Paget's bone disease, osteoporosis, and hypercalcemia of malignancy. This review surveys the cellular and molecular basis of these physiologic and clinical actions.

Meta-analyses of therapies for postmenopausal osteoporosis. VI. Meta-analysis of calcitonin for the treatment of postmenopausal osteoporosis

OBJECTIVE

To review the effect of calcitonin on bone density and fractures in postmenopausal women.

DATA SOURCE

We searched MEDLINE and EMBASE from 1966 to 2000 and examined citations of relevant articles and the proceedings of international osteoporosis meetings. We contacted osteoporosis investigators to identify additional studies and primary authors for unpublished data.

STUDY SELECTION

We included 30 studies that randomized women to calcitonin or an alternative (placebo or calcium and/or vitamin D) and measured bone density or fracture incidence for at least 1 yr.

DATA EXTRACTION

For each trial, three independent reviewers assessed the methodological quality and abstracted data.

DATA SYNTHESIS

Calcitonin reduced the incidence of vertebral fractures, with a pooled relative risk (RR) of 0.46 [95% confidence interval (CI) 0.25-0.87, P = 0.02, n = 1404, 4 trials]. However, the RR from the one relatively large randomized controlled trial (RCT) was 0.79 (95% CI 0.62-1.00, P = 0.05, n = 1108). For nonvertebral fractures, the pooled RR was 0.52 (95% CI 0.22-1.23, P = 0.14, n = 1481, 3 trials). Once again, the single large trial showed a less impressive effect than the smaller trials (RR 0.80, 95% CI 0.59-1.09, P = 0.16, n = 1245). For bone density of the lumbar spine, the pooled weekly dose of 250 to 2800 IU per week resulted in significant increase in the weighted mean difference (WMD) of 3.74 (2.04-5.43, P < 0.01, n = 2260, 24 trials). The combined forearm showed a similar effect, with a WMD of 3.02 (95% CI 0.98-5.07, P < 0.01, n = 468, 9 trials). At the femoral neck, the pooled weighted mean difference showed a nonsignificant trend toward benefit, WMD 3.80 (95% CI -0.32-7.91, P = 0.07, 9 trials, n = 513). Methodologically weaker studies tended to show greater effects on bone density, and the lumbar spine results suggested the possibility of publication bias.

CONCLUSIONS

Calcitonin likely increases bone density in postmenopausal women predominantly at the lumbar spine and forearm for weekly doses of greater than 250 IU, although the true effect may be smaller than the pooled estimate would suggest. Calcitonin likely reduces the risk of vertebral fracture; its effect on nonvertebral fracture remains uncertain.

Calcitonin for the long-term prevention and treatment of postmenopausal osteoporosis

Calcitonin is a powerful inhibitor of osteoclast activity that exerts a rapid, transient, and reversible inhibition of bone resorption. Prolonged administration of parenteral calcitonin, by injections of 100 IU every 1 or 2 days, can prevent postmenopausal or postovariectomy bone loss, and is also able to increase trabecular bone mass among patients presenting an established osteoporosis. Prolonged treatment with calcitonin injections is, however, difficult to maintain over the long run. In addition to the ease of administration compared with the injectable forms, nasal calcitonin is much better tolerated, the side effects being rare and generally negligible. A prolonged administration of 200 IU intranasal calcitonin acutely inhibits parameters of bone resorption and can increase lumbar spine bone mineral density (BMD) by 1.7%-3.3% after 1 year. Lower doses also appear to be efficient to prevent early postmenopausal bone loss, but the data are conflictual. The results are more consistent in patients who already suffer from established osteoporosis. The increase in lumbar spine BMD is in the order of 1%-2% after 1 year with 200 IU daily. A therapeutic benefit of calcitonin at the level of the cortical bone has been less well demonstrated than for the trabecular bone. As for other antiosteoporotic therapies, the effect of calcitonin on the reduction of fracture risk has been examined less than the beneficial effect on trabecular bone mass. Currently, there is still no prospective, placebo-controlled study with a sufficient number of patients that demonstrates that long-term parenteral calcitonin administration reduces the risk of osteoporotic fractures. The efficacy of nasal calcitonin treatment to reduce vertebral fracture rate has been best examined in the PROOF (Prevent Recurrence of Osteoporotic Fractures) study. This was a prospective 5-year, placebo-controlled, dose-response study of nasal calcitonin (100, 200, or 400 IU daily). The increase in lumbar spine BMD was modest but significant and not clearly dose dependent, as was the reduction in bone turnover. The relative risk of developing new vertebral fractures was reduced by 33% at the end of the study in the 200-IU dose group (relative risk = 0.67, 95% CI 0.47-0.97, p = 0.03). There was also a nonsignificant reduction in the risk of hip fracture in this dose group. The doses of 100 and 400 IU of calcitonin also reduced the vertebral fracture risk, but the difference did not reach the classical level of statistical significance. A possible effect of calcitonin to enhance bone quality, which cannot be assessed by routinely available methods, is currently being investigated in a prospective placebo-controlled trial that could provide a rational explanation for these effects of calcitonin on the reduction in the vertebral fracture rate without much increase in bone mass or a marked reduction in bone turnover.

Forty years of calcitonin--where are we now? A tribute to the work of Iain Macintyre, FRS

Calcitonin was discovered as a hypocalcemic principal that was initially thought to originate from the parathyroid gland. This view was corrected subsequently, and an origin from the thyroid C cells was documented. The purification and sequencing of various calcitonins soon followed. Calcitonin is a 32-amino-acid-long peptide with an N-terminal disulfide bridge and a C-terminal prolineamide residue. The peptide was shown to potently inhibit bone resorption; however, a direct osteoclastic action of the peptide was confirmed only in the early 1980s. Several osteoclast calcitonin receptors have subsequently been cloned and sequenced. Specific regions of the receptor necessary for ligand binding and intracellular signaling through cyclic AMP and calcium have been identified through systematic deletion mutagenesis and chimeric receptor studies. Calcitonin's potent antiresorptive effect has led to its use in treating Paget's disease of bone, osteoporosis, and hypercalcemia. This review retraces key aspects of the synthesis and structure of calcitonin, its cellular and molecular actions, and its therapeutic uses as they have emerged over the 40 years since its discovery. The review also examines the implications of these findings for future clinical applications as a tribute to early workers to whom credit must be given for creation of an important and expanding field. Notable are the new approaches currently being used to enhance calcitonin action, including novel allosteric activators of the calcitonin receptor, modulation of the release of endogenous calcitonin by calcimimetic agents, as well as the development of oral calcitonins.

An update on glucocorticoid-induced osteoporosis

In general, bone loss from glucocorticoid treatment occurs rapidly within the first 6 months of therapy. Glucocorticoids alter bone metabolism by multiple pathways; however, the bone loss is greatest in areas rich in trabecular bone. Preventive measures should be initiated early. It is the author's opinion that all subjects initiating treatment with prednisone at 7.5 mg or greater require calcium supplementation (diet plus supplement) at a dose of 1500 mg and vitamin D at a dose of 400 to 800 IU/d. If the patient is going to remain on this dose of glucocorticoid for more than 4 weeks, an antiresorptive agent should be started (e.g., estrogen, bisphosphonate, raloxifene). If a patient has established osteoporosis and is either initiating glucocorticoid therapy or is chronically treated with prednisone at 5 mg d or greater in addition to calcium and vitamin D supplementation, a potent antiresorptive agent (bisphosphonate) should be started. A bone mineral density measurement of either the lumbar spine or the hip may be helpful is assessing an individual's risk of osteoporosis, may improve compliance with treatment, and can be used to monitor the efficacy of the prescribed therapy. There is no reason to withhold treatment for glucocorticoid-induced bone loss until a bone mass measurement is taken, however. In motivated patients, a weight-bearing and resistance exercise program should be prescribed to help retain muscle strength and prevent depression. If hypercalciuria develops with glucocorticoid use, either thiazide diuretics or sodium restriction may be helpful. In patients who continue to lose bone or experience fracture's despite antiresorptive therapy while on glucocorticoids, bone-building anabolic agents (e.g., hPTH 1-34 or PTH 1-84) may be available someday soon.

Preventing fractures in postmenopausal women with osteoporosis. A review of recent controlled trials of antiresorptive agents

The evidence from randomised, controlled trials of the ability of antiresorptive treatments to reduce the risk of fractures in postmenopausal women with osteoporosis is reviewed and summarised. The aminobisphosphonates, alendronic acid and risedronic acid, and the selective estrogen receptor modulator raloxifene have all been shown to reduce the incidence of radiographic vertebral fractures. Only alendronic acid and risedronic acid have been shown to reduce the incidence of non-spine fractures in women with postmenopausal osteoporosis. There is evidence of antifracture efficacy for calcium plus vitamin D, primarily in a nursing home setting or in people with low intakes of these nutrients. Furthermore, since both the placebo and active treatment groups received calcium and vitamin D in most controlled trials of antiresorptive agents, it appears that the other agents provide benefits beyond those of calcium and vitamin D alone. There is insufficient published evidence from randomised controlled trials to convincingly support the antifracture efficacy of other agents, including calcitonin, estrogen and etidronic acid, at this time. Data from observational studies suggest, however, that estrogen and etidronic acid may have antifracture efficacy in this population.

Use of calcitonin for the treatment of an odontoid fracture. Case report

The authors report on the efficacy of nonsurgical treatment of an older patient with a fractured odontoid process. The patient, an 85-year-old woman, had multiple medical problems that put her at an increased surgery-related risk. Therefore, an alternative approach was elected, including immobilization with a Philadelphia collar and the provision of calcitonin nasal spray. Bone union and clinical recovery were achieved within 8 weeks of initiating the nasal calcitonin therapy (12 weeks postinjury). Considering the patient's age, comorbidities, and the severity of the fracture, the recovery period was unusually short. The authors believe that calcitonin played a pivotal role in the healing process of the fractured odontoid bone. There is no question that the fusion in this patient could be unrelated to the medical therapy. This description of one patient, as well as the lack of a large randomized study, precludes any scientific conclusions. Nevertheless, the authors believe that the development of a successful fusion in this high-risk patient should be reported as an observation that merits confirmation and study. The authors also discuss the physiological effects of calcitonin and the research and clinical experience with this hormone in different conditions affecting bone.

Steroid-induced osteoporosis in systemic lupus erythematosus

The patient with SLE is at considerable risk of osteoporosis, because of the inflammatory disease itself, its consequences, and its treatments. Because of their extensive use, glucocorticoids are thought to be the most frequent cause of drug-related osteoporosis and may be responsible for much of the bone loss in lupus. This article focuses on the mechanisms of steroid-induced osteoporosis in SLE and outlines strategies for prevention and treatment.

Birth and death of bone cells: basic regulatory mechanisms and implications for the pathogenesis and treatment of osteoporosis

The adult skeleton regenerates by temporary cellular structures that comprise teams of juxtaposed osteoclasts and osteoblasts and replace periodically old bone with new. A considerable body of evidence accumulated during the last decade has shown that the rate of genesis of these two highly specialized cell types, as well as the prevalence of their apoptosis, is essential for the maintenance of bone homeostasis; and that common metabolic bone disorders such as osteoporosis result largely from a derangement in the birth or death of these cells. The purpose of this article is 3-fold: 1) to review the role and the molecular mechanism of action of regulatory molecules, such as cytokines and hormones, in osteoclast and osteoblast birth and apoptosis; 2) to review the evidence for the contribution of changes in bone cell birth or death to the pathogenesis of the most common forms of osteoporosis; and 3) to highlight the implications of bone cell birth and death for a better understanding of the mechanism of action and efficacy of present and future pharmacotherapeutic agents for osteoporosis.

A review of clinical trials of therapies for osteoporosis using fracture as an end point

As the population ages, fragility fractures grow in importance as a public health problem. The principal goal of osteoporosis therapy is primary and secondary fracture prevention. A growing choice of therapies is now available for the treatment of osteoporosis. In this article, we review their efficacy using fracture prevention as an end point. The considerable heterogeneity among studies with regard to patient age, past fracture history, fracture site, and analytical methods precludes the possibility of performing a meaningful meta-analysis. Fracture outcomes have been reported in clinical trials with calcium supplementation, vitamin D supplementation, estrogen replacement therapy (ERT), calcitonin, etidronate, alendronate, sodium fluoride (NaF), parathyroid hormone (PTH), and raloxifene. Compelling evidence for fracture prevention has been provided for calcium and vitamin D supplementation and alendronate treatment. Evidence of fracture prevention exists for ERT, raloxifene, calcitonin, etidronate, and PTH. Data on NaF are inconsistent. Across agents, there is a trend toward greater efficacy for patients at greatest risk of fracture.

Does the French general practitioner correctly investigate and treat osteoporosis? Groupe Rhumatologique d'Etudes Cliniques de Midi-Pyrénées

In our region, more than half the patients with osteoporosis are investigated and treated by general practitioners. We carried out two surveys to discover whether the diagnosis and treatment of osteoporosis were correctly carried out by general practitioners in the Midi-Pyrénées region. The first survey concerned 85 patients who had been diagnosed with osteoporosis by their general practitioner. These patients were being seen for the first time in a hospital or private practice setting by a rheumatologist who completed a questionnaire based solely on the history taken from the patient and the records in the patient's possession. For the second survey, 200 general practitioners who had referred patients to the rheumatology department were sent a questionnaire on their management of osteoporosis. Fifty-two physicians completed and returned the questionnaire. More than half the general practitioners started treatment of osteoporosis without fractures on the basis of standard spinal X-rays where the radiologist suggested bone mineral loss. The initial biological investigation was correctly carried out by only 6% of physicians. Treatment was correctly prescribed in only 34% of cases of osteoporosis with fractures, 50% of osteoporosis without fractures and 50% of senile cortical osteoporosis.

The role of calcitonin in the prevention of osteoporosis

This article discusses calcitonin as an alternative for patients with established osteoporosis who cannot, will not, or should not proceed with estrogen replacement therapy. Clinical trial data for calcitonin in both injectable and nasal spray formulations and for both lower-dose and higher-dose regimens are presented.

Calcitonin alters bone quality in beagle dogs

Because of its antiresorptive properties, calcitonin is widely used to prevent and treat osteoporosis. A stimulatory effect of calcitonin on osteoblasts has also been reported; however, a recent histologic study points to a negative effect of calcitonin on mineralization of cancellous bone. The present experiment was performed to determine whether the observed histological signs of alterations in mineralization are also observed in cortical bone and whether this results in changes in mechanical properties, mineral densities, or mineral properties of canine bone. Sixteen female adult beagle dogs were randomly allocated to receive either human calcitonin at a dose of 0.25 mg/dog (50 IU, n = 8) or vehicle (mannitol, n = 8) every other day for 16 weeks. At the end of the study, the dogs were euthanized. Both tibiae, L1 and L5 vertebrae, and iliac crest bone samples were excised and defleshed. Torsional mechanical properties of tibial diaphyses and compressive strengths of vertebrae were measured. Bone mineral densities (BMD) of tibiae and vertebrae were measured by using dual-energy X-ray absorptiometry. Ultrastructural mineral characteristics of iliac crest bone were determined by gravimetry and Fourier transform infrared spectroscopy (FTIR). Bone histomorphometry was performed in the cortical envelope of the iliac crest. Tibiae from dogs treated with calcitonin withstood significantly less maximum torque until failure, required less torsional energy to reach the maximum torque, and had less torsional stiffness than the tibiae from dogs treated with vehicle (p < 0.05). Cancellous cores of vertebrae from calcitonin-treated dogs withstood less compressive mechanical loading than did vertebral cores from vehicle-treated animals (p < 0.05). Dogs treated with calcitonin had less BMD of both tibiae and vertebrae than vehicle-treated animals (p < 0.05). Bones from calcitonin-treated dogs had significantly less ash content, which correlated with the lower phosphate-to-amide I (detected by FTIR) and greater carbonate-to-phosphate ratios than did bones from vehicle-treated dogs (p < 0.05). Calcitonin-treated dogs exhibited a decrease in bone formation and mineralization rates and an increase in mineralization lag time. These results point to a negative effect of calcitonin on bone quality. These findings are intriguing and call for further studies addressing whether the observed abnormalities are transient or permanent.

The effect of a modified etidronate cyclical regimen on postmenopausal osteoporosis: a four-year study

To develop an improved treatment schedule for osteoporosis, a study was undertaken in 100 postmenopausal women using a modified ADFR 90-day cyclical regimen with etidronate. After one year of treatment, the etidronate-treated group showed a significant increase in bone density of the spine, which continued over the following 2 years of treatment and remained stable during the fourth year. In contrast, in the non-etidronate group, bone density decreased significantly after four years. In addition, the fracture rate was significantly lower in the etidronate group than in the non-etidronate group. Side effects were minimal in both groups and no serious adverse reactions were reported. In conclusion, it appears that a cyclical regimen using 1,25-dihydroxyvitamin D3, etidronate and calcium increases bone mass and reduces fractures with no significant side effects, thus making a useful contribution in the treatment of postmenopausal osteoporosis.

The management of osteoporosis

The management of osteoporosis used to centre upon investigation and treatment of patients with fracture. The spectrum has now widened to include the detection of patients at high risk of fracture before a fracture occurs. This is best achieved by consideration of clinical risk factors and the selective use of bone densitometry. The frequency of osteoporotic fractures in elderly women is such that detailed investigation of such patients is often not necessary unless the patient's bone density is outside the normal range for age. When bone density is inexplicably low, secondary causes of osteoporosis should be sought by appropriate investigations. Fracture prevention involves a correction of lifestyle factors (stopping smoking, moderating alcohol intake etc.) and achieving a total calcium intake of 1-1.5 g/day. The first line for pharmacological intervention is hormone replacement therapy because of its proven efficacy and the extensive data available documenting its safety. The bisphosphonates have comparable effects on bone density and fractures in studies extending for up to 3 years, and are increasingly used, particularly in older patients and those reluctant to take hormone replacement therapy. Other available agents have significant drawbacks, either with respect to side-effects or inconsistent documentation of efficacy and should be used only in special circumstances.

Calcitonin versus etidronate for the treatment of postmenopausal osteoporosis: a meta-analysis of published clinical trials

This review examines the evidence on the efficacy of calcitonin and etidronate in the prevention of osteoporosis and osteoporotic fractures. MEDLINE was searched for clinical trials calcitonin or etidronate and reviews of the treatment of postmenopausal osteoporosis. The reference sections of the papers retrieved were again searched for trials on the treatments of interest. Two people independently collected data from the trials that met the inclusion criteria of the study. Weighted means in the change in bone mineral density (BMD) and differences in vertebral fracture rates were computed for calcitonin and etidronate separately. The existence of publication bias was investigated by funnel plots of effect size against sample size. Eighteen clinical trials and calcitonin and six with etidronate were included in the meta-analysis. The pooled change in vertebral BMD at the end of the studies was 1.97 (95% CI 1.77 to 2.17) with calcitonin and 3.20 (95% CI 2.92 to 3.48) with etidronate. Pooled change in proximal femur BMD was 0.32 (95% CI -0.27 to 0.91) with calcitonin and 2.42 (95% CI 2.16 to 2.68) with etidronate. The aggregated number of vertebral fractures prevented by the treatment was 59.2 per 1000 patient-years (95% CI 55.1 to 63.3) for calcitonin and 28.3 (95% CI 26.2 to 30.4) for etidronate. With the available evidence we cannot establish the superiority of either of the two drugs for the treatment of postmenopausal osteoporosis. The clinical trials are particularly lacking in data on hip fracture, the most important consequence of osteoporosis. In this situation consideration of the relative costs of the drugs is prominent.

Salmon calcitonin nasal spray : An effective alternative to estrogen therapy in select postmenopausal women

The efficacy and safety of estrogen replacement therapy (ERT) and salmon calcitonin in the treatment of postmenopausal osteoporosis are reviewed with special consideration given to patients for whom ERT, the primary antiresorptive therapy for osteoporosis, is not indicated, tolerable, or is refused. The various formulations of estrogen and salmon calcitonin, for which the nasal spray formulation was recently approved for use in the United States, are reviewed in depth with reference to dose ranges, side effects, and convenience. Data regarding increases in bone mineral density (BMD) produced by each agent are presented. Specifically, the range of increases in BMD induced by ERT and salmon calcitonin are comparable. Given the substantial public health consequences of postmenopausal osteoporosis and osteoporotic fractures, the primary care physician is increasingly faced with the need to educated and recruit postmenopausal patients to appropriate therapy with the optimal agent for that particular patient. In the many patients who are unable or unwilling to accept, initiate, and comply with prescribed ERT, alternative therapeutic options are necessary Based on the established safety profile of salmon calcitonin, ease of administration, an uncomplicated dosing regimen, no reported drug interactions, and the lack of uterine bleeding associated with ERT or gastrointestinal adverse effects of other agents used to treat osteoporosis, salmon calcitonin nasal spray is an appropriate alternative approach for the treatment of postmenopausal bone loss.

Intranasal salcatonin (salmon calcitonin). A review of its pharmacological properties and role in the management of postmenopausal osteoporosis

Osteoporosis is a common problem among postmenopausal women and is associated with significant morbidity, mortality and costs primarily resulting from osteoporotic fractures. Salcatonin (salmon calcitonin) inhibits osteoclastic bone resorption and is approximately 40 to 50 times more potent than human calcitonin. In most randomised trials in which intranasal salcatonin (usually 50 to 200 IU/day plus oral calcium supplements) was administered for 1 to 5 years to postmenopausal women for prevention of osteoporosis, bone mineral density or content of the lumbar spine increased by approximately 1 to 3% from baseline. In contrast, postmenopausal women receiving only oral calcium supplements typically had reductions in bone mineral density or content of about 3 to 6%. The difference between treatment groups was statistically significant in essentially all studies. Although changes in bone mineral density or content were broadly similar in studies of postmenopausal women with established osteoporosis to those in postmenopausal women receiving therapy for prevention of the disease, studies in women with established osteoporosis did not usually demonstrate statistically significant differences between treatment groups. Also in postmenopausal women with established osteoporosis, intranasal salcatonin reduced pain and/or analgesic consumption in some trials and, in a limited number of studies of relatively short duration (i.e. < or = 2 years), the incidence of osteoporotic fractures. A large multicentre 5-year study with adequate statistical power to confirm the effect of intranasal salcatonin on reducing osteoporotic fracture rates in postmenopausal women is currently under way. The intranasal formulation of salcatonin offers a more convenient and better tolerated alternative to the parenteral formulation of the drug which is administered by regular subcutaneous or intramuscular injections. Adverse events associated with the intranasal formulation are generally mild and transient, usually involving local reactions such as nasal discomfort, rhinorrhoea or rhinitis. Thus, for postmenopausal women unable or unwilling to tolerate long term hormone replacement therapy, intranasal salcatonin is an attractive alternative for the management of osteoporosis.

Calcitonin prevents bone loss but decreases osteoblastic activity in ovariohysterectomized beagle dogs

The antiresorptive effects of calcitonin are well documented. Recent in vitro and in vivo evidence points to an anabolic effect of calcitonin on osteoblasts. To assess the value of calcitonin in preventing the rapid and early bone loss after cessation of ovarian function and to investigate its effects on osteoblasts in vivo, 32 dogs were ovariohysterectomized (OHX) and 32 dogs were sham-operated (Sham). After the surgeries, half of the OHX and Sham dogs received every-other-day subcutaneous injections of human calcitonin (0.25 mg/dog/d), and the remaining dogs were given vehicle. Half of the animals had a bone biopsy at week 2 and were euthanized thereafter; the other half of the animals underwent a bone biopsy at month 1 and were euthanized at month 4. Blood drawings were done at baseline and at the time of each bone biopsy. Calcitonin prevented the increase in erosion depth seen in OHX animals and prevented the cancellous bone loss observed at 2 weeks and at 1 and 4 months. Calcitonin did not affect bone volume in Sham dogs. However, treatment with calcitonin induced a decrease in mineralizing surfaces and bone formation rates at the bone surface and cell level and an increase in mineralization lag time in both Sham and OHX animals without significantly affecting osteoblast number. This finding indicates that the negative effect of calcitonin on bone mineralization is not solely the result of a decrease in bone turnover. The data show that calcitonin, because of its antiresorptive effects, can prevent bone loss after cessation of ovarian function. However, short-term treatment with calcitonin does not stimulate osteoblast activity; on the contrary, it exerts a negative effect on osteoblastic bone formation and mineralization. Long-term studies are needed to investigate whether this unwanted effect of calcitonin on osteoblasts in vivo represents a transitory or persistent phenomenon.

Osteoporotic fractures: background and prevention strategies

OBJECTIVES

To review current knowledge of the epidemiology, pathogenesis, prevention and treatment of osteoporosis, with particular reference to issues related to the menopause.

METHODS

Peer-reviewed publications were assessed.

RESULTS

Much international variation exists in the prevalence of osteoporosis and the incidence of fracture. Risk fractures for osteoporosis are numerous. The menopause and other causes of hypogonadism in both women and men strongly predispose to osteoporosis. Various endocrinopathies, especially glucocorticoid excess, also are important. The contribution of family history may be explained by one or more genetic markers. Poor vitamin D and calcium nutrition, smoking, high alcohol consumption and inactivity increase risk. Reduced bone mass is a major risk factor for fracture, although the magnitude of that risk may vary between populations. In addition, bone fragility, length of the femoral neck (for hip fracture), history of prior fracture (for vertebral fracture) and falls affect fracture risk. Useful methods for measuring bone density are available for both epidemiologic surveillance and for clinical practice. Dual energy x-ray absorptiometry is the most desirable method in clinical care settings. Some risk factors can be modified for prevention of osteoporosis. Postmenopausal bone loss can be inhibited with estrogen or estrogen plus progestin therapy. Bone loss in the elderly may be moderated with calcium and vitamin D supplementation. Maintenance of muscle tone and strength through exercise may reduce falls. CONCLUSIONS. Osteoporosis is a large and growing health problem in many countries. Prevention of osteoporosis is a high priority, especially because treatment of the established disease remains sub-optimal. Prevention requires immediate, intermediate-term and long-term strategies. First line therapy for established osteoporosis in women in many countries is estrogen or estrogen plus progestin, calcium and vitamin D. Prospects for improved prevention of osteoporotic fractures are encouraging.

Ultrasound parameters in osteoporotic patients treated with salmon calcitonin: a longitudinal study

Speed of sound (SOS) and broadband ultrasound attenuation (BUA) of ultrasound (US) in bone have been proposed as alternatives to radiation-based methods for the quantitative assessment of osteoporosis. However, the usefulness of US in monitoring response to treatment in osteoporotic patients has yet to be defined. To compare US with bone mineral density (BMD), we studied 112 osteoporotic women (age range 50-64 years). Seventy-eight of them were treated with salmon calcitonin nasal spray (CT; 200 IU/day, 1 month on and 1 month off) and calcium (500 mg/day); 34 patients were given only calcium. One hundred and four women complied with treatment throughout the 2-year study period. At baseline and after 1 and 2 years we measured BMD at lumbar spine by dual-energy X-ray absorptiometry (DXA), and SOS, BUA and Stiffness index, by an Achilles ultrasound unit. Moreover, biochemical markers of bone turnover (alkaline phosphatase, osteocalcin and hydroxyproline) were also measured at baseline and after 6, 12 and 24 months. In the calcitonin-treated group at the end of the study period BMD had increased by 1.99%, SOS by 0.20%, BUA by 0.88% and Stiffness by 2.12%. By contrast in the calcium-treated group all parameters had decreased (BMD, -2.66%; SOS, -0.55%; BUA, -3.30%; Stiffness, -6.0%) by the end of the study period. The differences between groups were significant for BMD, SOS and Stiffness. At baseline a significant, but weak correlation was found between BMD and US parameters. The correlation coefficients between percentage changes at the end of the study period, in BMD and in SOS, BUA and Stiffness, were all significant (p < 0.001), being 0.41, 0.53 and 0.57 respectively. In conclusion, ultrasound measurements carried out in conjunction with BMD measurements will yield a more comprehensive assessment of skeletal status and may be helpful in monitoring the response to treatment in osteoporotic patients.

Calcitonin for prevention and treatment of postmenopausal osteoporosis

Prolonged calcitonin administration (intramuscular, subcutaneous, or intranasal) can prevent postmenopausal trabecular bone loss. Nasal administration constitutes a particularly attractive option for women who cannot tolerate or benefit from estrogen replacement therapy. The optimal schedule of administration still has to be precised, but 100 U/day of nasal calcitonin, combined with calcium supplements, can currently be recommended. Interrupted regimens are maybe favourable. Calcitonin can also prevent further bone loss in established osteoporosis particularly if bone turnover is increased. The anti-fracture efficacy of calcitonin is suggested by different types of studies but has not been formally demonstrated. Lastly, its analgesic efficacy in cases of painful vertebral compression fractures has been demonstrated in controlled studies.

Postmenopausal osteoporosis: patient choices and outcomes

OBJECTIVE

Only two medications, estrogen and injectable salmon calcitonin, are currently approved by the FDA for the treatment of osteoporosis. Oral etidronate has been investigated but not approved for osteoporosis therapy. We compared the three available anti-resorptive medications in untreated osteoporotic women.

DESIGN

A nonrandomized, open label trial. After baseline biochemistry and bone mineral density (BMD) determinations, subjects self-selected therapy based on descriptions of the three drugs which were similar for all patients. Bone densitometry of the lumbar spine, femoral neck and distal and proximal forearm sites was repeated every 6 months.

RESULTS

Twenty-one patients chose estrogen, 20 chose etidronate and 11 chose calcitonin. Fear of breast cancer was the most common reason given for not choosing estrogen therapy. Mean age was slightly lower and spine and hip bone densities slightly higher in the estrogen group compared with both the etidronate and calcitonin groups. In the lumbar spine, all three agents resulted in similar small increments (mean increments 1.2-4.4% at 2 years). In the estrogen group, there was no change in femoral neck density while there were significant losses in both calcitonin and etidronate groups (3.1-4.9%). In the forearm, there was either no change (distal site) or an increment (proximal site) in the estrogen group, while both etidronate and calcitonin groups demonstrated a mean loss at both sites over the 2-year observation period.

CONCLUSIONS

These preliminary results suggest that all three agents appear equally effective at maintaining or increasing BMD of the lumbar spine, while estrogen appeared more effective at maintaining or increasing BMD of the appendicular skeleton. This study underscores the need for an alternative to estrogen therapy which is equally effective and can be given orally for those in whom estrogen is either contraindicated or undesirable.

Total and regional bone mineral content and fracture rate in postmenopausal osteoporosis treated with salmon calcitonin: a prospective study

Seventy-two postmenopausal osteoporotic women having more than one nontraumatic vertebral crush fracture were studied. Thirty-six of them, aged 68.8 +/- 1.2 years (18 +/- 4 YSM-years since menopause), were treated with 100 IU/day of salmon calcitonin i.m. plus 500 mg of elemental calcium for 10 days each month. The remaining 36 patients, aged 69.6 +/- 1.4 years (19 +/- 3 YSM), were given only 500 mg of elemental calcium for 10 days each month. All patients underwent clinical and analytical evaluation every 3 months. Radiological evaluation, assessment of vertebral deformities, and metacarpal radiogrammetry were done every 6 months. Densitometric measurements of total and regional bone mass were made every 12 months. At 24 months, the calcitonin group showed a 60% reduction in the number of new fractures and the group receiving only calcium had a 45% increase (P < 0.001). The incidence of vertebral fractures was 0.07 per patient-year in the group treated with calcitonin and 0.45 per patient-year in the group treated with calcium (P < 0.001). At 2 years, the calcitonin group showed a 12% increase in cortical bone mass on metacarpal radiogrammetry, a 16% increase in the axial skeleton on trunk densitometry, a 3.5% increase in total body bone mineral content, a 30.7% increase in pelvic bone mineral content, and a 6.2% increase in arm bone mineral content (all P < 0.001). In the group treated with calcium alone there was a loss of bone mass in every region. These findings suggest that salmon calcitonin is effective in the treatment of osteoporosis and show that it acts on cortical and trabecular bone.

Calcitonin in the Prevention and Therapy of Osteoporotic Syndromes

It is now generally accepted that estrogen status, exercise and adequate calcium intake are the singularly most important factors which guarantee the assumption of genetically programmed peak bone mass. Physicians also recognize that estrogen replacement therapy is not only essential to prevent bone loss in the early postmenopausal female, but also for the long-term preservation of bone mineral density. The efficacy of either continuous or intermittent calmon calcitonin administration in preventing further bone loss and in some instances decreasing fracture incidences in established osteoporotic syndromes is currently well established. As noted during a variety of controlled investigations performed both in the United States and abroad, and in the Physician's Resource Manual on Osteoporosis published by the United States National Osteoporosis Foundation, salmon calcitonin is also effective in early postmenopausal women who are not candidates for estrogen replacement therapy in addition to those patients with established osteoporosis. The practicing physician should acknowledge that of all the anti-resorptive agents recommended for therapy in osteoporotic syndromes, estrogens and salmon calcitonin are currently the only two drugs recommended by the U.S. Food and Drug Administration (USFDA) as safe and effective as treatment modalities in osteoporosis.

Effect of nandrolone decanoate and 1-alpha-hydroxy-calciferol on patients with vertebral osteoporotic collapse. A double-blind clinical trial

Eighty-eight postmenopausal women with at least one vertebral collapse were randomly assigned to two groups of 44 patients each. All patients were treated for a period of 12 months with 50 mg of nandrolone decanoate every 3 weeks or 1 microgram of 1-alpha-hydroxy-calciferol daily. Both groups received an identical placebo of the inactive drug. Pain intensity was significantly decreased in the nandrolone group and mobility was improved. Patients treated with vitamin D metabolite had also a beneficial but less obvious clinical result. Bone mineral measurements showed an increase of 5% in the nandrolone decanoate group, but a 2.5% decrease in the vitamin D metabolite group. Biochemical results showed a significant hypercalciuric effect of vitamin D metabolite, while nandrolone decanoate caused a reduction in calcium/creatinine excretion. No difference in serum lipids was found during the annual treatment in both groups. It is concluded that nandrolone decanoate has a beneficial effect in clinical symptoms, bone mineral density and biochemical parameters in patients with established osteoporotic vertebral fractures.

Effect of intranasal salmon calcitonin therapy on bone mass and bone turnover in early postmenopausal women: a dose-response study

We examine the dose-related effect of intranasal salmon calcitonin (sCT) on the early postmenopausal bone loss and bone turnover; a 2-year, prospective, randomized, double-blind, placebo-controlled study was carried out with 134 healthy women who had passed a natural menopause within 6 months to 3 years. The women were allocated randomly to 2 years of treatment with either 100, 200, or 400 IU of sCT given intranasally or placebo. All groups received a calcium supplement of 500 mg. Twenty-one women left the study before its end and 91 complied with the study criteria throughout. Bone mineral content/density of the distal forearm and lumbar spine and biochemical parameters of bone turnover were measured. Although the measurements after 24 months revealed no significant difference between groups in bone mineral density of the lumbar spine, the average changes over time revealed prevention of bone loss in the groups treated with 200 and 400 IU of sCT (0.2 to -0.6%) and declines of 0.8-1.7% in the groups treated with 100 IU of sCT and placebo (P < 0.05-0.01; within-group testing). There was no dose-related response to sCT but there was a significant difference between the pooled groups treated with 200 plus 400 IU of sCT versus the 100 IU sCT and placebo-treated groups (P = 0.030-0.005). The same difference between groups was seen for biochemical parameters of bone turnover (P = 0.022-0.003). The biochemical parameters of bone turnover revealed decreases of 10-20% (P < 0.001; within group testing) in the groups treated with the two highest sCT doses.(ABSTRACT TRUNCATED AT 250 WORDS)

Estimation of the effect of salmon calcitonin in established osteoporosis by biochemical bone markers

We reviewed data on 42 postmenopausal women with established osteoporosis (forearm fracture or a low bone mass) who had been randomly treated for 1 year with either rectal salmon calcitonin (sCT), 100 IU daily (n = 25) or nasal sCT, 200 IU daily (n = 17) applying an estimation algorithm for bone loss rates. Both groups received a daily calcium supplement of 500 mg. A group of 18 age-matched women who received no treatment served as controls. The bone mineral content of the distal forearm (BMCarm) was measured every 3 months by single photon absorptiometry. The individual rates of change during the 1-year period were calculated by linear regression analysis (alpha BMCarm). Bone loss rates were estimated initially and after 1 year of therapy by measurements of serum alkaline phosphatase, plasma bone Gla protein, and fasting urinary hydroxyproline and calcium (both corrected for creatinine excretion) according to the estimation algorithm. Both administration forms revealed significant control group-corrected decreases in serum and urine markers of bone turnover of 15-40% (P < 0.05-0.01) and positive outcomes of 2% in alpha BMCarm (P < 0.01). The estimated effect on bone mass was expressed as the difference between the bone loss estimated after 1 year and initially (delta ESTBIO). A significant correlation was seen between alpha BMCarm and delta ESTBIO (r = 0.5, P < 0.0001). We conclude that the effect of sCT on bone can be followed up by biochemical markers for bone turnover, i.e., by an annual blood and fasting urine sample, applying an estimation algorithm for the rate of bone loss.