Osteoporosis: trials and tribulations

Effects of fluoride intake on cortical and trabecular bone microstructure at early adulthood using multi-row detector computed tomography (MDCT)

PURPOSE

The aim of this study was to examine the effects of period-specific and cumulative fluoride (F) intake on bone at the levels of cortical and trabecular bone microstructural outcomes at early adulthood using emerging multi-row detector computed tomography (MDCT)-based novel techniques.

METHODS

Ultra-high resolution MDCT distal tibia scans were collected at age 19 visits under the Iowa Bone Development Study (IBDS), and cortical and trabecular bone microstructural outcomes were computed at the distal tibia using previously validated methods. CT scans of a tissue characterization phantom were used to calibrate CT numbers (Hounsfield units) into bone mineral density (mg/cc). Period-specific and cumulative F intakes from birth up to the age of 19 years were assessed for IBDS participants through questionnaire, and their relationships with MDCT-derived bone microstructural outcomes were examined using bivariable and multivariable analyses, adjusting for height, weight, maturity offset (years since age of peak height velocity (PHV)), physical activity (questionnaire for adolescents (PAQ-A)), healthy eating index version 2010 (HEI-2010) scores, and calcium and protein intakes.

RESULTS

MDCT distal tibia scans were acquired for 324 participants from among the total of 329 participants at age 19 visits. No motion artifacts were observed in any MDCT scans, and all images were successfully processed to measure cortical and trabecular bone microstructural outcomes. At early adulthood, males were observed to have stronger trabecular bone microstructural features, as well as thicker cortical bone (p < 0.01), as compared to age-similar females; however, females were found to have less cortical bone porosity as compared to males. Among participants with available F intake estimates (75 to 91% of the 324 with MDCT scans, depending on the period-specific F intake measure), no statistically significant associations were detected between any period-specific or cumulative F intake and bone microstructural outcomes of the tibia at the p < 0.01 level. Only for females, statistically suggestive associations (p < 0.05) were found between recent F intake (from 14 to 19 years) and trabecular mean plate width and trabecular thickness at the tibia. Those associations became somewhat weaker, but still statistically suggestive, for trabecular thickness in fully adjusted analysis with height, weight, PHV, calcium and protein intake, and HEI-2010 and PAQ-A scores as covariates.

CONCLUSION

The findings show that the effects of lifelong or period-specific F intake from combined sources for adolescents typical to the United States Midwest region are not strongly associated with bone microstructural outcomes at age 19 years. These findings are generally consistent with previously reported results of IBDS analyses, which further confirms that effects of lifelong or period-specific F intake on skeletons in early adulthood are absent or weak, even at the levels of cortical and trabecular bone microstructural details.

Prevalence and patterns of bone loss in the first year after renal transplant in South East Asian patients

BACKGROUND

Limited data are available regarding patterns of bone loss in South East Asian renal transplant patients. We aimed to determine the prevalence of low bone density and factors contributing to bone loss in Singaporean patients in the first year after renal transplant.

METHODS

Seventy-nine consecutive patients who underwent renal transplant were evaluated. Bone mineral density (BMD) was evaluated at 0 (baseline), and at 6 and 12 months after transplant. Baseline parathyroid hormone and vitamin D levels were also assessed. Multivariate regression models were used to investigate the relationship between the different variables and BMD.

RESULTS

Thirty-six patients (45.6%) had low BMD at baseline. Factors correlating with the low BMD were older age, postmenopausal status, and tertiary hyperparathyroidism (P<0.0005, 0.009, and 0.027, respectively). There was a linear decrease in total hip and lumbar spine BMD from baseline to 12 months, the decrease from baseline to 6 months being significant (P=0.019 for total hip and P<0.0005 for lumbar spine). Patients with tertiary hyperparathyroidism had a greater risk of decrease in BMD at 6 months compared with patients with secondary hyperparathyroidism (odds ratio=13.5, confidence interval: 1.3, 144.4) and with those who had parathyroidectomy (odds ratio=34.9; confidence interval: 2.0, 598.8).

CONCLUSIONS

The prevalence of low BMD in this population of renal transplant recipients was high. Parathyroid status was the only independent factor that correlated with low BMD at baseline and subsequent bone loss highlighting the critical role of this hormone in bone metabolism after renal transplant.

Long-term therapy in COPD: any evidence of adverse effect on bone?

Patients with COPD have high risk for osteoporosis and fractures. Hip and vertebral fractures might impair mobility, and vertebral fractures further reduce lung function. This review discusses the evidence of bone loss due to medical treatment opposed to disease severity and risk factors for COPD, and therapeutic options for the prevention and treatment of osteoporosis in these patients. A review of the English-language literature was conducted using the MEDLINE database until June 2009. Currently used bronchodilators probably lack adverse effect on bone. Oral corticosteroids (OCS) increase bone resorption and decrease bone formation in a dose response relationship, but the fracture risk is increased more than reflected by bone densitometry. Inhaled corticosteroids (ICS) have been associated with both increased bone loss and fracture risk. This might be a result of confounding by disease severity, but high doses of ICS have similar effects as equipotent doses of OCS. The life-style factors should be modified, use of regular OCS avoided and use of ICS restricted to those with evidenced effect and probably kept at moderate doses. The health care should actively reveal risk factors, include bone densitometry in fracture risk evaluation, and give adequate prevention and treatment for osteoporosis.

Bone loss. An emerging problem following obesity surgery

The incidence of obesity worldwide has increased markedly in the past 2 decades, with estimates of increases of 50% in the United States alone. Research indicates that weight loss produced by diet alone is not sustained and that 75% of dieters regain most of the weight lost within 1 year and 90% within 2 years. Morbid obesity is associated with comorbid conditions, including heart disease, hypertension, diabetes, mechanical arthropathy, sleep apnea, and numerous other serious disorders and a shortened life expectancy. Because of limited success with medical management, surgical treatment of morbid obesity has been used increasingly, especially with the development of laparoscopic procedures, including Roux-en-Y gastric bypass (RYGB). RYGB is associated with low surgical mortality, marked decreased food intake, and significant, sustained weight loss. However, in this emerging, unique population there is growing appreciation that these procedures may be associated with the development of bone loss and skeletal fragility because of altered nutrient metabolism. Despite the threat of skeletal fragility and fracture, there is limited data addressing the effects of bariatric surgery on bone metabolism and bone loss.

Patient treatment preferences for osteoporosis

OBJECTIVE

To examine patient preferences for currently available and promising osteoporosis treatment options.

METHODS

We recruited patients who had recently (within 2 weeks) undergone bone densitometry and were found to have osteoporosis. Consenting participants completed an Adaptive Conjoint Analysis questionnaire to determine their treatment preferences for oral bisphosphonates taken once per week, intravenous bisphosphonates administered every 3 months, intravenous bisphosphonates administered once per year, and subcutaneous recombinant human parathyroid hormone (rhPTH). We performed simulations based on respondents' values for route of administration, absolute reduction in risk of vertebral and hip fractures over 5 years, and risk of adverse effects to predict each respondent's treatment choice.

RESULTS

The study sample included 201 women and 11 men (median age 73). Patients' treatment preferences were strongly influenced by route of administration. Patients' preferred treatment option, across all simulations, was bisphosphonates. Among 80 treatment-naive participants, 52 (65%) preferred an annual infusion over oral weekly bisphosphonates. Participants with poorer perceived health status, those with a high perceived risk of future fracture, and participants preferring to treat health problems without doctors or prescription drugs were more likely to prefer an annual infusion over weekly pills.

CONCLUSION

Patient preferences for osteoporosis treatment options are strongly influenced by route of administration. Therefore, despite the added benefits of rhPTH, patients' preferred treatment option for osteoporosis is bisphosphonates. Among those preferring bisphosphonates, many preferred annual infusions over weekly oral medications, emphasizing the need to incorporate individual patient preferences into treatment decisions for osteoporosis. The latter is especially important given the poor rates of long-term adherence to osteoporosis medications.

Type 2 diabetes mellitus in nursing home patients: effects on bone turnover, bone mass, and fracture risk

CONTEXT

Fractures are a major health burden in elderly institutionalized persons. Type 2 diabetes mellitus (DM) has a high prevalence in nursing home patients and has been associated with positive effects on bone mass in younger, community-dwelling elderly.

OBJECTIVE

The objective of this study was to investigate whether type 2 DM affects bone mass, bone turnover, or prospective fracture rates in frail, elderly women living in nursing homes.

DESIGN, SETTING, AND PARTICIPANTS

This study was a prospective cohort of 583 patients with type 2 DM and 1081 control (CTR) individuals above age 70 recruited from 95 nursing homes in Austria. Patients were enrolled and followed up by mobile study teams.

MAIN OUTCOME MEASURES

We performed quantitative bone ultrasound measurements at the calcaneus, radius, and proximal third phalanx, measurements of quadriceps strength, and biochemical parameters of mineral metabolism and bone turnover. Patients were prospectively followed for hip and other nonvertebral fractures over 2 yr.

RESULTS

Patients with type 2 DM had significantly higher age-, weight-, and mobility score-adjusted calcaneal stiffness (P < 0.0001), radial speed of sound (P < 0.005), and phalangeal speed of sound (P < 0.05) measurements when compared with CTRs. Mean serum PTH (-20.7%) and osteocalcin levels (-22.3%) were significantly lower (both P < 0.0001) in patients with treated type 2 DM despite comparable low serum 25-hydroxyvitamin D levels and slightly higher adjusted total serum calcium levels compared with CTRs. Important independent determinants of bone turnover in both patient groups were PTH, creatinine clearance, alanine aminotransferase, as well as glycosylated hemoglobin levels, together accounting for 30-40% of its variance. A total of 110 hip fractures occurred during the observation period, corresponding to a hip fracture rate of 3.1% (in CTRs) and 3.4% (in type 2 DM) per 100 patient years; this was not significantly different for CTRs and diabetics.

CONCLUSIONS

Decreased PTH levels and higher levels of glycemia independently contribute to lower bone turnover in elderly nursing home patients with type 2 DM. Despite higher bone mass and lower bone turnover, hip fracture risk is comparable with women without DM.

Drug delivery systems for hormone therapy

Various types of formulations and delivery devices have been developed for hormone therapy (HT) and their modes of hormone action and patient responses have been evaluated. Although the Women's Health Initiative (WHI) reported the controversial results on estrogen/progestin combination therapy, HT still remains a primary therapeutic option for the treatment of menopausal symptoms and osteoporosis. As a novel alternative to HT may not be probable in clinical use for the next decade, the currently available formulations containing estrogen and progestogen should be properly optimized for HT. The extensive reviews and comparisons on the characteristics of various types of HT could lead to the development of an efficient delivery formulation which maximizes patient compliance and minimizes adverse effects for individual users.

Are osteoporotic fractures being adequately investigated? A questionnaire of GP & orthopaedic surgeons

Background

To investigate the current practice of Orthopaedic Surgeons & General Practitioners (GP) when presented with patients who have a fracture, with possible underlying Osteoporosis.

Methods

Questionnaires were sent to 140 GPs and 140 Orthopaedic Surgeons. The participants were asked their routine clinical practice with regard to investigation of underlying osteoporosis in 3 clinical scenarios.

55 year old lady with a low trauma Colles fracture

60 year old lady with a vertebral wedge fracture

70 year old lady with a low trauma neck of femur fracture.

Results

Most doctors agreed that patients over 50 years old with low trauma fractures required investigation for osteoporosis, however, most surgeons (56%, n = 66) would discharge patients with low trauma Colles fracture without requesting or initiating investigation for osteoporosis. Most GPs (67%, n = 76) would not investigate a similar patient for osteoporosis, unless prompted by the Orthopaedic Surgeon or patient.

More surgeons (71%, n= 83) and GPs (64%, n = 72) would initiate investigations for osteoporosis in a vertebral wedge fracture, but few surgeons (35%, n = 23) would investigate a neck of femur fracture patient after orthopaedic treatment.

Conclusion

Most doctors know that fragility fractures in patients over 50 years old require investigation for Osteoporosis; however, a large population of patients with osteoporotic fractures are not being given the advantages of secondary prevention.

Estrogen and skin: The effects of estrogen, menopause, and hormone replacement therapy on the skin

Aging is associated with declining levels of several hormones, including estrogen. Although the effects of estrogen on the skin are still not fully understood, it is known that, in women, declining estrogen levels are associated with a variety of cutaneous changes, many of which can be reversed or improved by estrogen supplementation. Estrogens are C-18 steroids synthesized from cholesterol in the ovary premenopausally and in the peripheral tissue in postmenopausal women. Two estrogen receptors, alpha and beta, have been cloned and found in various tissue types. Studies of postmenopausal women indicate that estrogen deprivation is associated with dryness, atrophy, fine wrinkling, poor healing, and hot flashes. Epidermal thinning, declining dermal collagen content, diminished skin moisture, decreased laxity, and impaired wound healing have been reported in postmenopausal women. This article reviews the effects of declining estrogen levels on the skin and the effects of estrogen supplementation.

LEARNING OBJECTIVE

At the conclusion of this learning activity, participants should be familiar with the pathways of estrogen synthesis, sites of estrogen receptors, age-dependent variations in serum estrogen concentration, the changes seen in postmenopausal skin, and the effects of estrogen supplementation.

Transient disturbance in physeal morphology is associated with long-term effects of nitrogen-containing bisphosphonates in growing rabbits

Bisphosphonates have clinical benefit in children with severe osteogenesis imperfecta or osteoporosis and potential benefit in children with Perthes disease or undergoing distraction osteogenesis. However, there is concern about the effects of bisphosphonates on the physis and bone length. In 44 growing rabbits, zoledronic acid caused a transient disruption of physeal morphology, retention of cartilaginous matrix in trabeculae and cortical bone of the metaphysis, and a minor decrement in tibial bone length at maturity.

INTRODUCTION

Data from growing animal models suggest that bisphosphonates cause retention of longitudinal cartilaginous septa at the chondro-osseous junction, extension of trabeculae to the metaphyseal-diaphyseal junction, and varying dose-dependent effects on longitudinal growth. However, there is a lack of data regarding effects of intermittent use of nitrogen-containing bisphosphonates on the physis and on tibial length in models reaching maturity.

MATERIALS AND METHODS

Contralateral tibias of juvenile rabbits were examined after right tibial distraction osteogenesis from two previous studies. Animals were randomized to receive 0.1 mg/kg zoledronic acid (ZA) IV at 8 weeks of age (ZA*1) or 8 and 10 weeks of age (ZA*2) or saline. Body mass was analyzed from 5 to 44 weeks of age; tibial length and proximal physeal-metaphyseal histology and histomorphometry were analyzed at 8-52 weeks of age.

RESULTS

Tibial length was 3% less at 14 weeks of age in the ZA*2-treated versus saline group (p<0.05) in both studies, and this difference persisted at maturity in the long-term study group (26 weeks of age, p<0.05). Total body mass gain from 5 to 26 weeks of age was 14% less in ZA*2-treated than saline animals (p<0.05). Rate of weight gain from 8 to 10 weeks of age was 76% less in ZA*2 compared with saline animals (p<0.05). Radiographs showed radiodense lines in the metaphyses of ZA-treated bones, corresponding to the number of doses. Histologically, lines resulting from the first dose of ZA contained longitudinal cartilaginous matrix cores surrounded by bone, whereas those from the second dose contained spherical cores of matrix caused by transient disruption of physeal morphology after the first dose of ZA. Resorption of these lines at later times was radiographically and histologically evident, but remnants of cartilaginous matrix remained in the cortical bone of ZA-treated animals.

CONCLUSIONS

ZA treatment within the final 13.5% of the rabbit tibial growth period caused a transient disruption in physeal morphology and resorption associated with retention of cartilaginous matrix and coinciding with a persistent 3% decrement in tibial length. Disruption of physeal morphology and potential loss of bone length should be considered when administering nitrogen-containing bisphosphonates to children before closure of the major physes.

Compliance with drug therapies for the treatment and prevention of osteoporosis

OBJECTIVES

This study used paid claims data from real-world treatment settings to investigate the impact of hormone replacement therapy (HRT), bisphosphonate and raloxifene on patients with a recorded diagnosis of osteoporosis.

METHODS

Data from a large health insurer were used to identify 58,109 osteoporosis patients who initiated drug therapy for osteoporosis. Multivariate statistical models were developed for duration of therapy, compliance at 1 year, time to discontinuation or a change in therapy, health care costs and risk of fracture over 1 year.

RESULTS

One-year compliance rates were below 25% for all osteoporosis therapies. The mean unadjusted duration of continuous therapy was 221 days for raloxifene, 245 days for bisphosphonate, 262 for estrogen-only and 292 days for estrogen plus progestin. Raloxifene patients were consistently less compliant than estrogen-only patients after adjusting for differences in patient characteristics. Estrogen plus progestin patients were generally more compliant while bisphosphonate did not differentiate from estrogen-only. Compliance reduced the risk of hip fracture (o.r. = 0.382, P < 0.01) and vertebral fracture (o.r. = 0.601, P < 0.05). Compliant patients used fewer physicians services (-US dollars 56, P < 0.0001), hospital outpatient services (-US dollars 38, P < 0.05) and hospital care (-US dollars 155, P < 0.01). Bisphosphonate patients were twice as likely as estrogen-only patients to experience vertebral, Colles and other fractures and experienced higher health care costs (+US dollars 420, P < 0.01). The effectiveness of both raloxifene and bisphosphonate medications relative to estrogen-only improved significantly with the age of the patient.

CONCLUSIONS

Compliance with drug therapies for osteoporosis over 1 year is poor leaving patients at risk for fractures and higher health care costs.

Transient retention of endochondral cartilaginous matrix with bisphosphonate treatment in a long-term rabbit model of distraction osteogenesis

Bisphosphonates induce major increases in strength of callus in distraction osteogenesis in the short term. Poor understanding of the underlying mechanism, however, raises concerns about long-term consequences. In this long-term study in 32 rabbits, zoledronic acid transiently increased trabeculae by delayed temporal progression of endochondral bone remodeling but did not prevent radiographic completion of bone repair.

INTRODUCTION

We hypothesized that bisphosphonate inhibition of osteoclast-mediated resorption would retain bone during repair, producing a larger callus in the short term. However, if remodeling was not restored, completion of the bone repair process in the long term could be jeopardized.

MATERIALS AND METHODS

Juvenile rabbits underwent right tibial osteotomy and 2 weeks of distraction, followed by a period of consolidation. Animals received saline (controls) or zoledronic acid (ZA; 0.1 mg/kg at surgery and again 2 weeks later), and distracted tibias were examined by radiograph, DXA, histology, and histomorphometry at 2, 4, 6, 18, and 44 weeks after surgery.

RESULTS

Regenerated bone in ZA-treated animals was denser than controls on radiographs at 6 weeks and had more distinct radiodense trabeculae and retention of original cortices at 18 weeks. By 44 weeks, controls and ZA-treated animals were radiographically healed and indistinguishable. Regenerate BMD and BMC increased between 2 and 4 weeks in all animals, with a greater effect in ZA. At 6 weeks, BMD and BMC in ZA-treated animals were 1.6- and 2-fold greater, respectively, than controls (p < 0.01). From 6 to 44 weeks, the control values gradually increased and approached the ZA-treated values. Regenerate bone volume and trabecular number by histomorphometry were from 1.6- to 2-fold greater in ZA-treated animals at 6 and 18 weeks (p < 0.05). Endochondral cartilaginous matrix volume was up to 2.4-fold greater in ZA-treated animals at 2 and 4 weeks (p < 0.05). TRACP+ cells in ZA-treated animals were larger with more nuclei. Mineral apposition rate and osteoblast number and surface were lower in ZA-treated animals at 6 weeks (p < 0.01) but not at later times.

CONCLUSIONS

Disruption of TRACP+ cell function by ZA during bone regeneration seems to lead to an accretion of cancellous bone built on a larger endochondral cartilaginous matrix and increased bone mass, consistent with reported increases in short-term callus strength. This increase in bone mass, caused by a delay in remodeling, provided a transient advantage without preventing radiographic completion of the bone repair process in the long term. Noncontinuous treatment with nitrogen-containing bisphosphonates thus can have short-term beneficial effects without preventing long-term bone repair.

High-dose alendronate uncouples osteoclast and osteoblast function: a study in a rat spine pseudarthrosis model

The effect of alendronate on osteoclast and osteoblast function was studied in a novel spine pseudarthrosis model in rats. Sixty-three Sprague-Dawley rats were divided into three groups: control group (saline), therapeutic dose group (1 microg/kg/week), and one-log overdose group (10 microg/kg/week). Animals had L4-L5 posterior intertransverse process fusion with limited bone graft and were sacrificed at 2, 4, and 6 weeks. Manual palpation showed no notable differences among groups. Treatment group radiographic scores were equal to or better than control group scores and were higher than the overdose group at 2 and 6 weeks. Qualitatively, limited histologic remodeling and poor osteoclastic and osteoblastic function were noted in the alendronate treated groups. Quantitative histologic analysis showed fewer osteoclasts in the therapeutic and high-dose groups (p < 0.001). The percent osteoblasts per bone surface area was lower in the high-dose group (p < 0.05). The results suggest that the effect of alendronate was dose dependent and animal model dependent and that supranormal doses of alendronate had a deleterious effect on osteoclastic and osteoblastic function in this model.

Postmenopausal hormone therapy: the pros and cons

The use of postmenopausal hormone therapy (HT) has recently generated much debate following the results of various large randomised controlled trials. This has challenged physicians to reassess the use of HT in each individual woman within the realm of her symptomatology and risk profile for long-term illnesses. There are several areas of definite benefit or risk and many areas of uncertainty. The results of recent randomised controlled trials pertain to the specific HT regimens used and the characteristics of the study groups, such that the conclusions cannot be extrapolated to the use of HT in general.

Hyperprolactinemia and bone mineral density: the potential impact of antipsychotic agents

The prevalence of schizophrenia is about 1% worldwide. Individuals with schizophrenia are at increased risk for osteoporosis and fractures for several reasons, including poor diet, lack of exercise, cigarette smoking, and polydipsia. Some antipsychotic medications may further increase the risk of fractures by causing dizziness, orthostatic hypotension, and falls. Studies in women with hyperprolactinemia resulting from pituitary tumors have demonstrated high rates of osteoporosis believed to result from hypoestrogenism. Similarly, hyperprolactinemia in men results in hypogonadism and bone loss. Preliminary surveys have indicated that schizophrenia patients also may have elevated rates of osteoporosis and pathological fractures, possibly resulting in part from the long-term administration of antipsychotic agents that produce hyperprolactinemia and secondarily lower estrogen and testosterone levels. This potential complication of treatment with certain antipsychotic agents requires careful study and could represent a serious public health problem.

Long-term treatment of incadronate disodium accumulates microdamage but improves the trabecular bone microarchitecture in dog vertebra

This study aimed to investigate the effect of long-term suppression of bone resorption by bisphosphonate on the microstructure, accumulation of microdamage, and mechanical properties of trabecular bone. Twenty-nine 1-year-old beagles (15 males, 14 females) were divided into three groups. The control group (CNT) was treated daily with vehicle, and the other two groups were treated with incadronate at a dose of 0.3 mg/kg/day (LOW) or 0.6 mg/kg/day (HIGH) orally for 3 years. After death, the second thoracic vertebra was scanned with microcomputed tomography (micro-CT) and assigned to histomorphometric and microdamage measurements. The fourth lumbar vertebra was mechanically tested by compression. Incadronate concentration in bone was measured in the 11th thoracic vertebra. Micro-CT analysis demonstrated a platelike trabecular structure and increased concave surface of trabeculae in the thoracic vertebra of incadronate-treated groups. Three-year incadronate treatment significantly suppressed trabecular activation rates by 56% in LOW and 67% in HIGH without impairment of mineralization, and increased microdamage accumulation in both incadronate-treated groups. Trabecular bone volume was significantly increased in both LOW and HIGH groups, and vertebral strength was significantly increased in the HIGH group compared with the CNT group. However, intrinsic material properties such as normalized ultimate stress and normalized toughness were reduced in incadronate-treated groups. Incadronate concentration in bone was dose-dependent. This study suggests that long-term suppression of bone remodeling increases microdamage accumulation, but this is not necessarily associated with vertebral fragility because of compensated increase of bone mass and improved microarchitecture.

What predicts early fracture or bone loss on bisphosphonate therapy?

Factors predicting early fracture or bone loss on bisphosphonate therapy are not well defined. We studied 1588 patients over the age of 50 yr who were started on cyclic etidronate (1119) or alendronate (469) in the CANDOO (Canadian Database for Osteoporosis and Osteopenia Patients) Study. Incident fracture within 2 yr of starting therapy occurred in 31 patients and was independently predicted by a previous history of nonvertebral fracture (odds ratio [OR], 2.98, 95% confidence interval [CI], 1.30, 6.83, p = 0.010). Two hundred and fifty-seven patients lost >/=3% bone mass at the hip or spine (early bone loss) while on bisphosphonate therapy. Protection from early bone loss was most strongly independently predicted by treatment with alendronate with no previous history of etidronate use (OR, 0.29, CI, 0.13, 0.62, p = 0.002). In conclusion, early fracture on bisphosphonate therapy is most strongly predicted by a previous history of fracture and early bone loss is most strongly predicted by the potency of the prescribed bisphosphonate.

Weight lifted in strength training predicts bone change in postmenopausal women

PURPOSE

The aim of this study was to examine the relationship between weight lifted in 1 yr of progressive strength training and change in bone mineral density (BMD) in a group of calcium-replete, postmenopausal women.

METHODS

As part of a large clinical trial, 140 calcium-supplemented women, 44-66 yr old, were randomized to a 1-yr progressive strength-training program. Half of the women were using hormone replacement therapy. Three times weekly, subjects completed two sets of six to eight repetitions in eight core exercises at 70-80% of one repetition maximum. BMD was measured at baseline and 1 yr.

RESULTS

In multiple linear regression, the increase in femur trochanter (FT) BMD was positively related to total weight lifted (0.001 g.cm (-2)) for a SD of weight lifted, P< 0.01) after adjusting for age, baseline factors, HRT status, weight change, cohort, and fitness center. The weighted squats showed the strongest (0.002 g.cm(-2)) for a SD of weight lifted, P< 0.001), whereas the back extension exhibited the weakest (0.0005 g.cm(-2)) for a SD of weight lifted, P< 0.26) association with change in FT BMD. The amount of weight lifted in the weighted march exercise was significantly related to total body BMD (0.0006 g.cm(-2)) for a SD of weight lifted, P< 0.01). The associations between weight lifted and BMD for the femur neck or lumbar spine were not significant.

CONCLUSION

Evidence of a linear relationship between BMD change and total and exercise-specific weight lifted in a 1-yr strength-training program reinforces the positive association between this type of exercise and BMD in postmenopausal women.

Oral bisphosphonates and upper gastrointestinal tract problems: what is the evidence?

OBJECTIVE

To review and evaluate the evidence regarding possible associations of bisphosphonate use with upper gastrointestinal (GI) tract adverse events (AEs).

METHODS

We reviewed and summarized published information and abstracts regarding upper GI tract safety and tolerability of bisphosphonates, including laboratory and animal studies, epidemiological (observational) studies, endoscopy studies, and randomized controlled trials (RCTs). The evidence was summarized by using the principles of evidence-based medicine, giving the greatest credence to high-quality RCTs.

RESULTS

Clinical reports of esophagitis associated with bisphosphonate use appear to have declined in frequency once the importance of proper administration was explained to physicians after early reports of complications. Conflicting results have been reported in endoscopy studies; some reported no significant increase in upper GI tract lesions, whereas others reported a higher incidence of gastric (but not esophageal) lesions among patients taking oral bisphosphonates. Endoscopy studies that reported differences were of short duration (2 weeks) and were not of double-blind design. Results from large RCTs involving thousands of participants detected no increase in upper GI tract AEs among individuals treated with bisphosphonates. Other studies of patients who discontinued taking bisphosphonates and were randomized to blinded re-treatment with either a bisphosphonate or placebo show that most patients (>85%) were able to continue treatment, with no difference in AEs between the bisphosphonate and placebo groups.

CONCLUSIONS

The highest level of evidence, RCTs, suggests little or no increase in risk of upper GI tract problems if bisphosphonates are administered properly. Upper GI tract symptoms are common among patients with osteoporosis. The evidence suggests that many upper GI tract AEs reported during therapy with bisphosphonates may reflect a high background incidence of upper GI tract complaints and an increased sensitivity to detection rather than a causal relationship to therapy.

Antiresorptive treatment of postmenopausal osteoporosis: comparison of study designs and outcomes in large clinical trials with fracture as an endpoint

Antiresorptive treatments for postmenopausal osteoporosis have been studied extensively, but due to the volume of published data and lack of head-to-head trials, it is difficult to evaluate and compare their fracture reduction efficacy. The objective of this review is to summarize the results from clinical trials that have fracture as an endpoint and to discuss the factors in study design and populations that can affect the interpretation of the results. Although there are numerous observational studies suggesting that estrogen and hormone replacement therapies may reduce the risk of vertebral and nonvertebral fractures, there is no large, prospective, randomized, placebo-controlled, double-blind clinical trial demonstrating fracture efficacy. The effects of raloxifene, alendronate, risedronate, and salmon calcitonin on increasing bone mineral density (BMD) and decreasing fracture risk have been shown in randomized, placebo-controlled, double-blind clinical trials of postmenopausal women with osteoporosis. Although the increases in lumbar spine BMD vary greatly in these trials, the decrease in relative risk of vertebral fractures is similar among therapies. However, nonvertebral fracture efficacy has not been consistently demonstrated. Combined administration of two antiresorptive therapies results in greater BMD increases, but the effects on fracture risk are unknown. Direct comparisons of clinical trial results should be considered carefully, given the differences in study design and populations. Differences in study design that may influence the efficacy of fracture risk reduction include calcium and vitamin D supplementation, primary fracture endpoints, definition of vertebral deformity or fracture, discontinuation rates, and statistical power. Factors in the study population that may influence fracture efficacy include the age of the population and the proportion of subjects with prevalent fractures. The use of surrogate endpoints such as BMD to predict fracture risk should be approached with caution, as the relationship between BMD changes and fracture risk reduction with antiresorptive therapies is uncertain. Consideration of these results from clinical trials can contribute to clinical judgment in selecting the best treatment option for postmenopausal osteoporosis.

The evidence that exercise during growth or adulthood reduces the risk of fragility fractures is weak

There has never been, and will never be, a randomized double-blind placebo-controlled trial demonstrating that exercise in youth, adulthood or old age reduces fragility or osteoporosis-related fractures in old age. The next level of evidence, a randomized, controlled but unblinded study with fractures as an end-point is feasible but has never been done. The basis for the belief that exercise reduces fractures is derived from lower levels of 'evidence', namely, retrospective and prospective observation cohort studies and case-control studies. These studies are at best hypothesis generating, never hypothesis testing. They are all subject to many systematic biases and should be interpreted with extreme scepticism. Surrogate measures of anti-fracture efficacy are the next level of evidence, such as the demonstration of a reduction in risk factors for falls, a reduction in falls, a reduction in fractures due to falls, an increase in peak bone size and mass, prevention of bone loss in midlife and restoration of bone mass and structure in old age.

Long-term effect of incadronate disodium (YM-175) on fracture healing of femoral shaft in growing rats

The aim of this study was to investigate the long-term effect of incadronate on fracture healing of the femoral shaft in rats. Female Sprague-Dawley 8-week-old rats were injected subcutaneously (sc) with either vehicle (V group) or two doses of incadronate (10 microg/kg and 100 microg/kg) three times a week for 2 weeks. Right femoral diaphysis was then fractured and fixed with intramedullary stainless wire. Just after fracture, incadronate treatment was stopped in pretreatment groups (P groups: P-10 and P-100) or continued in continuous treatment groups (C groups: C-10 and C-100). All rats were killed at 25 weeks or 49 weeks after surgery. Fractured femur was evaluated radiologically and mechanically and then stained in Villanueva bone stain and embedded in methyl methacrylate. Undecalcified cross-sections from the fracture area were evaluated microradiologically and histomorphometrically. Radiographic observation showed that the fracture line disappeared in all groups. Cross-sectional area in the C-100 group was the biggest among all groups and in the C-10 group was larger than that in the V group at 25 weeks. Histological and histomorphometric observations showed that the process of fracture healing was delayed under continuous treatment with incadronate as evidenced by the delay of both lamellar cortical shell formation and resolution of original cortex in C groups. Percent linear labeling perimeter, mineral apposition rate (MAR), and bone formation rate (BFR) in C groups significantly decreased compared with the other groups, indicating that the callus remodeling was suppressed under continuous treatment, especially with a high dose. Mechanical study showed that the stiffness and ultimate load of the fractured femur in the C 100 group were the highest among all groups at both 25 weeks and 49 weeks. In conclusion, this study showed that long-term continuous treatment with incadronate delayed the process of fracture healing of femur in rats, especially under high dose but it did not impair the recovery of mechanical integrity of the fracture.

Comparative safety of bone remodeling agents with a focus on osteoporosis therapies

This article reviews the different treatments currently available for osteoporosis and examines the benefits and adverse events that are associated with each. While emphasizing safety considerations, this review summarizes the following treatments for osteoporosis: calcium supplements, fluoride, hormone replacement therapy, raloxifene, bisphosphonates, salmon calcitonin, and calcitriol. Before prescribing any of these agents, the clinician should review the risk/benefit profile of each drug in the context of the individual patient's history, concomitant diseases, concurrent medications, and general physical condition.

Postmenopausal osteoporosis: fracture consequences and treatment efficacy vary by skeletal site

At least half of all postmenopausal women will experience fractures during their lifetime, and the consequences are often serious, but most women at risk are not receiving adequate treatment. The objective of this paper is to summarize the literature concerning the consequences of osteoporotic fractures, and the effectiveness of pharmacologic agents for preventing fractures and their consequences, emphasizing a systematic, evidence-based summary of treatment results from randomized, controlled trials that were published previously. Osteoporosis is associated with increased risk of fractures at most skeletal sites. Hip fractures have much greater prognostic significance in terms of health than any other single type of fracture. However, symptomatic vertebral fractures and other non-hip fractures also represent enormous morbidity and economic burdens, and signal increased risk of future fractures of all types, including the hip. There is convincing evidence that two bisphosphonates (alendronate and risedronate) reduce the risk of both spine and non-spine fractures. The evidence for reducing hip fracture risk is greater for alendronate, with a consistent approximately 50% reduction in hip fractures across studies. Alendronate has also been demonstrated to maintain quality of life by reducing outcomes such as hospitalization and bed rest related to back pain. Among other agents, raloxifene reduces the risk of vertebral fractures by approximately 30%; the published evidence for most other agents is inconclusive. Osteoporosis should be regarded as seriously as other important chronic disorders such as hypertension and hyperlipidemia. Postmenopausal patients with a high risk of fractures--such as those with prior fractures or osteoporosis as measured by BMD--need to be treated. Although other therapeutic modalities are available, the evidence is most convincing for the bisphosphonates, alendronate and risedronate.

Oim mice exhibit altered femur and incisor mineral composition and decreased bone mineral density

To investigate the role of the pro alpha 2(I) collagen chains of type I collagen in mineralization we used the oim (osteogenesis imperfecta model) mouse as our model system. The oim/oim mouse (homozygous for a null mutation in its COL1A2 gene of type I collagen) fails to synthesize functional pro alpha 2(I) collagen chains, synthesizing only homotrimers of pro alpha 1(I) collagen chains. To evaluate the role of pro alpha 2(I) collagen in type I collagen structure/function in mineralized tissues, we examined age-matched oim/oim, heterozygous (oim/+), and wild-type (+/+) mouse femurs and incisors for mineral composition (calcium, phosphorus, magnesium, fluoride, sodium, potassium, and chloride) by neutron activation analyses (NAA), and bone mineral content (BMC) and bone mineral density (BMD) by dual-energy X-ray absorptiometry (DEXA) in a longitudinal study (7 weeks to 16 months of age). NAA demonstrated that oim/oim femurs had significant differences in magnesium, fluoride, and sodium content as compared with +/+ mouse femurs, and oim/oim teeth had significant differences in magnesium content as compared to +/+ teeth. The ratio of calcium to phosphate was also significantly reduced in the oim/oim mouse femurs (1.58 +/- 0.01) compared with +/+ femurs (1.63 +/- 0.01). DEXA demonstrated that oim/oim mice had significantly reduced BMC and BMD as compared to oim/+ and +/+ mice. Serum and urine calcium, magnesium, and phosphorus levels, and Ca(47) absorption across the gut were equivalent in oim/oim and +/+ mice, with no evidence of hypercalciuria. These studies suggest that the known decreased biomechanical properties of oim/oim bone reflect both altered mineral composition as well as the decreased BMD, which further suggests that the presence of alpha2(I) chains plays an important role in mineralization.

Alendronate in the treatment of osteoporosis: a review of the clinical trials

Osteoporosis is a highly prevalent disease. More than half of postmenopausal women will experience fractures. Women at high risk (osteoporosis as measured by bone density, low trauma fractures of any type, or certain other risk factors) often require pharmacological therapy. However, surveys show that most women who have recently had fractures are currently not being treated. Recent results from the first megatrial of osteoporosis with >6400 participants, the Fracture Intervention Trial (FIT), have provided important advances in our understanding of osteoporosis and the efficacy of alendronate. The FIT study and other large clinical trials show that alendronate effectively increases bone density, reduces the risk of hip and vertebral fractures by approximately half within the first 12-18 months, and, most importantly, reduces the health consequences of fractures. Alendronate is also effective for preventing bone loss in early postmenopausal women. Thus, alendronate represents an important option for preventing and treating this common and debilitating disease. This article summarizes the wealth of data from FIT and other studies of alendronate in the context of the burden of illness associated with osteoporosis.

Mandibular bone formation rates in aged ovariectomized rats treated with anti-resorptive agents alone and in combination with intermittent parathyroid hormone

Anti-resorptive agents--including estrogen (E), calcitonin (CT), and bisphosphonates--are established in the treatment of osteoporosis. Intermittent administration of parathyroid hormone (PTH) stimulates bone formation and is a possible therapeutic agent for the restoration of bone mass. The purpose was to determine the effects of the anti-resorptive agents alone and in combination with intermittent PTH on bone formation in the mandible and a long bone in the aged ovariectomized (Ovx) rat. Female rats were ovariectomized or sham-operated. One year later, groups of Ovx rats were treated with E, CT, or the bisphosphonate, Risedronate (NE). Additional groups of Ovx rats were treated with each of these agents in combination with human PTH for 10 weeks. Estrogen treatment suppressed most indices of bone formation in the humerus and mandible, while NE decreased some indices of formation at the endocortical and endosteal surfaces of the mandible and humerus. Increased double-labeled surface and mineral apposition rates were observed only on the mandibular endosteal surfaces following CT treatment. When the anti-resorptive agents were combined with intermittent PTH, most indices of bone formation at all skeletal sites were substantially greater than those of the untreated Ovx controls as well as the E-, CT-, and NE-treated groups, respectively. These results provide additional evidence that established and emerging therapies for osteoporosis affect osseous tissues in the oral cavity, and this may influence the progression of diseases and/or aging changes at this site.

Selection of individuals for prevention of fractures due to bone fragility

Most patients with fractures go untreated because of the lack of awareness of osteoporosis. Treatment is indicated for women and men with osteoporosis and women and men with fractures with either osteoporosis or osteopenia because (a) fractures increase morbidity and mortality, (b) the burden of fractures is increasing because longevity is increasing, and (c) bone loss accelerates, rather than decelerates in old age. The indication for drug therapy is less clear in women or men with osteopenia because drugs have not been proved to reduce fracture risk in this group. There is no evidence that treating individuals with only risk factors reduces the fracture rate. Screening has not been shown to reduce the burden of fractures. Altering the bone mineral density by a few percent in the population is likely to reduce the number of fractures, but how this can be achieved is unknown. The rigorously investigated drugs reducing the spine fracture rate are alendronate, raloxifene and risedronate. Calcium and vitamin D reduce hip fractures in nursing home residents but not community-dwellers. In the community, only alendronate and risedronate have been reported to reduce hip fractures in randomized trials. The evidence for hormone replacement therapy is less satisfactory. It is likely to reduce the number of spinal fractures, but its role in hip fracture prevention is uncertain. Only alendronate has been reported to reduce spine fractures in men with osteoporosis. Evidence for the use of other drugs (calcitonin, fluoride, anabolic steroids and active vitamin D metabolites) in women or men is insufficient to justify their use.

Special considerations in breast cancer risk and survival

Experimental and clinical evidence suggests that breast neoplasia appears to be a hormone-dependent process that may also be influenced by dietary factors in many women. Conflicting reports on the relationship between exogenous hormones and the development, progression, and recurrence of breast cancer are critically examined in this report. The absolute breast cancer risk associated with either hormone replacement therapy or oral contraceptive use has not been clearly defined. Data from some large prospective studies have actually documented lower mortality rates for women taking hormone replacement compared with those for women who did not have hormone replacement therapy. In this regard, age, duration of use, and preexisting breast cancer risk factors must be taken into account. Although the results of two major prospective clinical trials addressing the role of timing of surgery within the menstrual cycle are forthcoming, the majority of studies have found no consistent association between timing of surgery and breast cancer survival. Recently reported prospective randomized data showing that selective-estrogen-receptor-modulators can act as effective chemoprevention agents in women at increased risk for breast cancer development are presented. Finally, information regarding the effect of dietary manipulation on breast cancer risk and survival is reviewed.

Health burden of hip and other fractures in Australia beyond 2000. Projections based on the Geelong Osteoporosis Study

OBJECTIVE

To calculate the expected increase in the number of fractures in adults attributable to the predicted increase in the number of elderly Australians.

DATA SOURCES

All fractures in adult residents (> or = 35 years) of the Barwon Statistical Division (total population, 218,000) were identified from radiological reports from February 1994 to February 1996. The Australian Bureau of Statistics supplied predictions of Australia's population (1996 to 2051).

MAIN OUTCOME MEASURE

The projected annual number of fractures in Australian adults up to 2051 (based on stable rates of fracture in each age group).

RESULTS

The number of fractures per year is projected to increase 25% from 1996 to 2006 (from 83,000 fractures to 104,000). Hip fractures are projected to increase 36% (from 15,000 to 21,000) because of a substantial rise in the number of elderly aged 85 years and over. Hip fractures are expected to double by 2026 and increase fourfold by 2051.

CONCLUSIONS

In contrast to Europe and North America, where numbers of hip fractures are expected to double by 2026 and then stabilise, in Australia hip fractures will continue to place a growing demand on healthcare resources for many decades. These projections can be used for setting goals and evaluating the costs and benefits of interventions in Australia.

The potential effect on hip fracture incidence of mass screening for osteoporosis

With ageing of the Australian population, treatment of osteoporosis-related hip fractures will impose an increasing burden on the healthcare system. Based on current age-adjusted hip fracture incidence and population projections for New South Wales, we estimated a 90% increase in hip fractures by the year 2021. Contributing significantly to this increase will be the number of men reaching the high risk age group for osteoporotic hip fractures. A suggested solution--screening and appropriate therapy for individuals at high risk of osteoporosis--may have only a modest impact. Our calculations show that, even with optimistic screening and therapy compliance rates, hip fractures could still increase by over 50%. Other approaches need to be further explored.

Etidronate and alendronate in the treatment of postmenopausal osteoporosis

OBJECTIVE

To review the clinical trials evaluating the efficacy of etidronate and alendronate in the treatment of established postmenopausal osteoporosis.

DATA SOURCE

A MEDLINE search was performed (from 1966 through September 1998) using the search terms bisphosphonates, etidronate, alendronate, and postmenopausal osteoporosis. English-language articles were considered for review.

STUDY SELECTION AND DATA EXTRACTION

Prospective, randomized, double-blind, placebo-controlled clinical trials using fracture as an end point were selected to review the efficacy of etidronate and alendronate in the treatment of postmenopausal osteoporosis. Results for the outcomes of bone mineral density (BMD) and fracture are summarized.

DATA SYNTHESIS

Etidronate and alendronate increase spinal BMD in postmenopausal women with osteoporosis. In one study, etidronate decreased the number of women sustaining new radiographic vertebral fractures over two years, but this effect was lost after three years of treatment. Alendronate reduces the number of radiographic vertebral fractures in postmenopausal women with a low bone mass. In women with preexisting fractures, alendronate decreases the number of patients with radiographic vertebral fractures, clinical (i.e., symptomatic vertebral and nonvertebral) fractures, and hip fractures. A significant reduction in the overall number of nonvertebral fractures has not been demonstrated in clinical trials evaluating either alendronate or etidronate.

CONCLUSIONS

No studies have directly compared the efficacy of alendronate and etidronate and the results of long-term clinical trials (i.e., >5 y) have not been published. Based on the results obtained in clinical trials using fracture as an end point, alendronate appears to be the bisphosphonate of choice. Safety profiles and cost should also be considered in the choice of etidronate or alendronate for the treatment of postmenopausal osteoporosis.

Hormone replacement therapy and breast cancer

The use of hormone replacement therapy by postmenopausal women with a history of breast cancer is a subject of considerable controversy. There are no scientific studies that have appropriately examined the issue, and current practice is often based on inferences from indirect evidence, anecdotal experience, and personal bias. Our understanding of the effects of exogenous, as well as endogenous, hormones on normal and neoplastic breast tissue provides some insights but is not an appropriate basis for clinical practice. The effects of exogenous hormone replacement on the overall health of postmenopausal women, including psychosocial issues, cardiovascular risks, and the morbidity of osteoporosis, must be understood before patients can be counseled appropriately. Treatment of patients must be individualized. The rapidly expanding area of nonhormonal therapies for the treatment of postmenopausal health risks and the treatment of symptomatic complaints in postmenopausal women has already led to a reevaluation of the use of exogenous hormones among all women. A prospective randomized trial that examines the effects of hormone replacement on women with a history of breast cancer is currently underway and will provide valuable data to address these issues. The aim of this review is to outline the scientific basis for the association between estrogen and breast cancer and to provide a framework in which individualized recommendations concerning the use of hormone replacement therapy can be made for patients with breast cancer.

Role of polypeptides in the treatment and diagnosis of osteoporosis

Osteoporosis is a common disorder characterized by reduced bone mineral density, deterioration of the microarchitecture of bone tissue and increased risk of fracture. The aim of treatment of osteoporosis is to maintain and, ideally, to restore bone strength safely. In recent years the role of polypeptide growth factors in bone metabolism has begun to appear. It has been proposed that alterations in the expression or production of growth factor can modulate the proliferation and activity of bone forming cells. In this direction, the role of structurally diverse peptides for the management and diagnosis of osteoporosis has attracted the attention of many investigators. This paper reviews numerous findings concerning the use of polypeptides, hormones, and growth factors, for the management of osteoporosis. Many of the compounds mentioned here are experimental prototypes of new therapeutic classes. Though it is unlikely that some of the compounds may ever be used clinically, development of safe and efficacious agents in each class will define the future course of therapy for osteoporosis.

Osteoporosis after organ transplantation

Within the past 2 decades, organ transplantation has become established as effective therapy for endstage renal, hepatic, cardiac, and pulmonary disease. Regimens to prevent rejection after transplantation commonly include high-dose glucocorticoids and calcineurin-calmodulin phosphatase inhibitors (the cyclosporines and tacrolimus), which are detrimental to bone and mineral homeostasis, and are associated with rapid bone loss that is often superimposed upon an already compromised skeleton. The incidence of fracture ranges from 8% to 65% during the first year after transplantation. In general, fracture rates are lowest in renal transplant recipients and highest in patients who receive a liver transplant for primary biliary cirrhosis. Rates of bone loss and fracture are greatest during the first 6 to 12 months after transplantation. Postmenopausal women and hypogonadal men appear to be at increased risk. Although no pretransplant densitometric or biochemical parameter has yet been identified that adequately predicts fracture risk in the individual patient, low pretransplant bone mineral density does tend to increase the risk of fracture, particularly in women. However, patients may sustain fractures despite normal pretransplant bone mineral density. Although the pathogenesis of the rapid bone loss is multifactorial, prospective biochemical data suggest that uncoupling of bone formation from resorption may be in part responsible, at least during the first 3 to 6 months. Prevention of transplantation osteoporosis should begin well before transplantation. Patients awaiting transplantation should be evaluated with spine radiographs, bone densitometry, thyroid function tests, serum calcium, vitamin D, parathyroid hormone, and testosterone (in men). Therapy for osteoporosis, low bone mass, and potentially reversible biochemical causes of bone loss should be instituted during the waiting period before transplantation. In patients with normal pretransplant bone density, therapy to prevent early posttransplant bone loss should be instituted immediately following transplantation. Most pharmacologic agents available for therapy of osteoporosis have not been subject to prospective controlled studies in organ transplant recipients. However, antiresorptive drugs, such as biphosphonates, appear to hold therapeutic promise.