Unresolved issues in osteoporosis in men

Sex-difference in bone architecture and bone fragility in Vietnamese

This study sought to define the sex-difference in trabecular and cortical bone parameters in Vietnamese individuals. The study involved 1404 women and 864 men aged between 20 and 86 years who were recruited from Ho Chi Minh City, Vietnam. Trabecular and cortical volumetric BMD were measured at the proximal tibia and proximal radius at 4%, 38%, and 66% points, using a peripheral quantitative computed tomography XCT2000 (Stratec, Germany). Polar strength strain index was estimated from cortical bone parameters. Changes in bone parameters were assessed by the multiple linear regression model. Among individuals aged 20–39 years, women had significantly lower peak trabecular BMD at both the radius (40%) and tibia (16%) than men, but the age-related reduction in trabecular BMD were similar between two sexes. For cortical BMD, peak values in women and men were comparable, but the age-related diminution was greater in women than men. At any age, polar strength strain index in women was lower than men, and the difference was mainly attributable to cortical bone area and total bone mass. We conclude that in the elderly, sex-related difference in trabecular BMD is originated during growth, but sex-related difference in cortical BMD is determined by differential age-related bone loss.

Development and Validation of Osteoporosis Risk-Assessment Model for Korean Men

PURPOSE

The aim of the present study was to develop an osteoporosis risk-assessment model to identify high-risk individuals among Korean men.

MATERIALS AND METHODS

The study used data from 1340 and 1110 men ≥50 years who participated in the 2009 and 2010 Korean National Health and Nutrition Examination Survey, respectively, for development and validation of an osteoporosis risk-assessment model. Osteoporosis was defined as T score ≤-2.5 at either the femoral neck or lumbar spine. Performance of the candidate models and the Osteoporosis Self-assessment Tool for Asian (OSTA) was compared with sensitivity, specificity, and area under the receiver operating characteristics curve (AUC). A net reclassification improvement was further calculated to compare the developed Korean Osteoporosis Risk-Assessment Model for Men (KORAM-M) with OSTA.

RESULTS

In the development dataset, the prevalence of osteoporosis was 8.1%. KORAM-M, consisting of age and body weight, had a sensitivity of 90.8%, a specificity of 42.4%, and an AUC of 0.666 with a cut-off score of -9. In the validation dataset, similar results were shown: sensitivity 87.9%, specificity 39.7%, and AUC 0.638. Additionally, risk categorization with KORAM-M showed improved reclassification over that of OSTA up to 22.8%.

CONCLUSION

KORAM-M can be simply used as a pre-screening tool to identify candidates for dual energy X-ray absorptiometry tests.

Fractal lacunarity of trabecular bone and magnetic resonance imaging: New perspectives for osteoporotic fracture risk assessment

Osteoporosis represents one major health condition for our growing elderly population. It accounts for severe morbidity and increased mortality in postmenopausal women and it is becoming an emerging health concern even in aging men. Screening of the population at risk for bone degeneration and treatment assessment of osteoporotic patients to prevent bone fragility fractures represent useful tools to improve quality of life in the elderly and to lighten the related socio-economic impact. Bone mineral density (BMD) estimate by means of dual-energy X-ray absorptiometry is normally used in clinical practice for osteoporosis diagnosis. Nevertheless, BMD alone does not represent a good predictor of fracture risk. From a clinical point of view, bone microarchitecture seems to be an intriguing aspect to characterize bone alteration patterns in aging and pathology. The widening into clinical practice of medical imaging techniques and the impressive advances in information technologies together with enhanced capacity of power calculation have promoted proliferation of new methods to assess changes of trabecular bone architecture (TBA) during aging and osteoporosis. Magnetic resonance imaging (MRI) has recently arisen as a useful tool to measure bone structure in vivo. In particular, high-resolution MRI techniques have introduced new perspectives for TBA characterization by non-invasive non-ionizing methods. However, texture analysis methods have not found favor with clinicians as they produce quite a few parameters whose interpretation is difficult. The introduction in biomedical field of paradigms, such as theory of complexity, chaos, and fractals, suggests new approaches and provides innovative tools to develop computerized methods that, by producing a limited number of parameters sensitive to pathology onset and progression, would speed up their application into clinical practice. Complexity of living beings and fractality of several physio-anatomic structures suggest fractal analysis as a promising approach to quantify morpho-functional changes in both aging and pathology. In this particular context, fractal lacunarity seems to be the proper tool to characterize TBA texture as it is able to describe both discontinuity of bone network and sizes of bone marrow spaces, whose changes are an index of bone fracture risk. In this paper, an original method of MRI texture analysis, based on TBA fractal lacunarity is described and discussed in the light of new perspectives for early diagnosis of osteoporotic fractures.

The p38α MAPK function in osteoprecursors is required for bone formation and bone homeostasis in adult mice

BACKGROUND

p38 MAPK activity plays an important role in several steps of the osteoblast lineage progression through activation of osteoblast-specific transcription factors and it is also essential for the acquisition of the osteoblast phenotype in early development. Although reports indicate p38 signalling plays a role in early skeletal development, its specific contributions to adult bone remodelling are still to be clarified.

METHODOLOGY/PRINCIPAL FINDINGS

We evaluated osteoblast-specific deletion of p38α to determine its significance in early skeletogenesis, as well as for bone homeostasis in adult skeleton. Early p38α deletion resulted in defective intramembranous and endochondral ossification in both calvaria and long bones. Mutant mice showed reduction of trabecular bone volume in distal femurs, associated with low trabecular thickness. In addition, knockout mice also displayed decreased femoral cortical bone volume and thickness. Deletion of p38α did not affect osteoclast function. Yet it impaired osteoblastogenesis and osteoblast maturation and activity through decreased expression of osteoblast-specific transcription factors and their targets. Furthermore, the inducible Cre system allowed us to control the onset of p38α disruption after birth by removal of doxycycline. Deletion of p38α at three or eight weeks postnatally led to significantly lower trabecular and cortical bone volume after 6 or 12 months.

CONCLUSIONS

Our data demonstrates that, in addition to early skeletogenesis, p38α is essential for osteoblasts to maintain their function in mineralized adult bone, as bone anabolism should be sustained throughout life. Moreover, our data also emphasizes that clinical development of p38 inhibitors should take into account their potential bone effects.

Osteoporosis in men

Osteoporosis in men causes significant morbidity and mortality. Bone health declines gradually, often insidiously; and in light of the advancing aging population poses a serious public health issue that is not well recognized. Studies of the past decade have expanded our understanding of the events within, as well as the regulation of, bone remodeling and provided better insight into the physiology and pathophysiology specific to the adult male skeleton. The clinical measurement of bone mineral density using dual-energy X-ray absorptiometry remains the gold standard for diagnosis of osteoporosis in males; and fracture risk assessment is now recognized as a preferred approach to guide treatment decisions. Utilizing surrogate end-points such as increasing bone mineral density and decreasing concentrations of bone resorption markers, clinical trials have demonstrated efficacy in pharmacological treatment of osteoporosis in the adult male. Unfortunately, few studies have evaluated the anti-fracture benefits in this population. Measurement of bone turnover markers may be an additional tool to monitor therapeutic responsiveness in addition to the measurement of bone mineral density.

Osteoporosis in men: epidemiology and treatment with denosumab

Osteoporosis is a major public health care concern. Although often described as a disease affecting postmenopausal women, researchers and clinicians have emphasized its prevalence in men in recent years. The National Osteoporosis Foundation has stated that up to 25% of men over the age of 50 years will experience a fracture due to osteoporosis. Men who suffer from a major fracture have higher mortality rates than women. Pharmacologic therapy options for treating osteoporosis are limited for men as compared with women, so each medication approved for use in this population represents an important clinical option. In September 2012, the US Food and Drug Administration approved a new indication for denosumab to increase bone mass in men with osteoporosis at high risk for fracture. Denosumab is a fully human monoclonal antibody and novel antiresorptive agent that works by binding receptor activator of nuclear factor kappa-β ligand (RANKL) and inhibiting the signaling cascade that causes osteoclast maturation, activity, and survival. Ultimately, denosumab suppresses bone turnover and increases bone mineral density in both trabecular and cortical bone. Approval for treating osteoporosis in men was based on data from the ADAMO trial which displayed efficacy in increasing bone mineral density at the lumbar spine, total hip, femoral neck, hip trochanter, and one-third radius. Studies indicate that denosumab is effective and safe, and has superior adherence rates and patient satisfaction. Although long-term data and further research on fracture reduction rates in men should be explored, at this time denosumab is one of several appropriate first-line treatment options for men with osteoporosis.

Distinct cyclosporin a doses are required to enhance bone formation induced by cyclic and rest-inserted loading in the senescent skeleton

Age-related decline in periosteal adaptation negatively impacts the ability to utilize exercise to enhance bone mass and strength in the elderly. We recently observed that in senescent animals subject to cyclically applied loading, supplementation with Cyclosporin A (CsA) substantially enhanced the periosteal bone formation rates to levels observed in young animals. We therefore speculated that if the CsA supplement could enhance bone response to a variety of types of mechanical stimuli, this approach could readily provide the means to expand the range of mild stimuli that are robustly osteogenic at senescence. Here, we specifically hypothesized that a given CsA supplement would enhance bone formation induced in the senescent skeleton by both cyclic (1-Hz) and rest-inserted loading (wherein a 10-s unloaded rest interval is inserted between each load cycle). To examine this hypothesis, the right tibiae of senescent female C57BL/6 mice (22 Mo) were subjected to cyclic or rest-inserted loading supplemented with CsA at 3.0 mg/kg. As previously, we initially found that while the periosteal bone formation rate (p.BFR) induced by cyclic loading was enhanced when supplemented with 3.0 mg/kg CsA (by 140%), the response to rest-inserted loading was not augmented at this CsA dosage. In follow-up experiments, we observed that while a 30-fold lower CsA dosage (0.1 mg/kg) significantly enhanced p.BFR induced by rest-inserted loading (by 102%), it was ineffective as a supplement with cyclic loading. Additional experiments and statistical analysis confirmed that the dose-response relations were significantly different for cyclic versus rest-inserted loading, only because the two stimuli required distinct CsA dosages for efficacy. While not anticipated a priori, clarifying the complexity underlying the observed interaction between CsA dosage and loading type holds potential for insight into how bone response to a broad range of mechanical stimuli may be substantially enhanced in the senescent skeleton.

The pathogenesis, treatment and prevention of osteoporosis in men

Testosterone stimulates longitudinal and appositional growth during childhood, whereas estrogen induces epiphysial closure. During adulthood, testosterone continues to stimulate periosteal growth, whereas estrogen is important for the maintenance of trabecular bone mass and structure. In males, testosterone is aromatized to estradiol. Both free and bioavailable plasma levels of testosterone and estradiol decrease with age in males, and fracture risk is associated with low estradiol levels. Testosterone may increase muscle mass and prevent fractures related to falls. Younger hypogonadal males should be treated with testosterone to attain peak bone mass and increase bone mineral density (BMD). Older hypogonadal males should be treated in cases of osteoporosis, reduced muscle strength and increased risk of falling. Secondary hyperparathyroidism caused by calcium and vitamin D insufficiency may reduce bone mass and strength and increase fracture risk and should be avoided. Since calcium supplementation has been associated with an increased risk of cardiovascular complications and renal stones, the dose should be tailored to the habitual daily calcium intake. Lifestyle-related risk factors (smoking, alcohol consumption, lack of physical activity and low body weight) should be addressed. The antifracture efficacy of antiresorptive and anabolic treatment for osteoporosis has not been documented in larger randomized controlled studies. However, changes in BMD and bone markers suggest similar effects in males and females of bisphosphonates (alendronate, risedronate, ibandronate, zoledronic acid), nasal calcitonin, denosumab and teriparatide (parathyroid hormone [1-34]). The antiresorptive drugs should be used in males with BMD T-score less than -2.5 and one or more risk factors, or with hip and vertebral fractures. It seems appropriate to recommend a higher cut-off T-score (e.g. less than -1.0 standard deviation [SD]) in glucocorticoid-induced osteoporosis and in patients receiving androgen deprivation therapy because of the fast initial bone loss. Anabolic treatment should be used in more severe spinal fracture cases, including glucocorticoid-induced osteoporosis.

The effect of age, sex hormones, and bone turnover markers on calcaneal quantitative ultrasonometry in healthy German men

The aim of this cross-sectional study was to determine the age-dependent variations of calcaneal quantitative ultrasonometry (QUS) and the association with sex hormones and biochemical bone turnover markers in a large sample of unselected healthy German men. Bone measurements are expected to behave differently among men and women. The speed of sound (SOS), broadband ultrasound attenuation (BUA), and stiffness index (SI) of the os calcaneus were measured in 506 German men aged 20-79 yr (mean age: 45.7 yr). Additionally, follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol, prolactin, testosterone, dehydroepiandrosterone sulfate (DHEA-S), sex hormone-binding globulin (SHBG) as well as N-terminal propeptide of human procollagen type I (PINP), C-terminal telopeptide of type I collagen (ICTP), osteocalcin, bone-specific alkaline phosphatase, and CrossLaps were measured with standardized essays and correlated with the QUS results. The QUS results comprised an overall change of 12.4%, 3.2%, and 23.2% for BUA, SOS, and SI, respectively, between the 20-29 and 70-79 yr age groups (p ≤ 0.001). The annual rate of the age-related differences was 0.33% (standard deviation [SD]: 0.31), 0.06% (SD: 0.08), and 0.53% (SD: 0.56) for BUA, SOS, and SI, respectively. Testosterone and DHEA-S were significantly associated with QUS parameters and increasing age, whereas SHBG showed an age-related increase and was inversely related with QUS values (p < 0.05). Bone turnover markers present lower values gradually, and we found a significant correlation between carboxy-terminal collagen crosslinks (CTX), osteocalcin (OC), bone alkaline phosphatase (BAP), and QUS variables (p < 0.05).

An age-dependent interaction with leptin unmasks ghrelin's bone-protective effects

The mutual interplay between energy homeostasis and bone metabolism is an important emerging concept. Ghrelin and leptin antagonize each other in regulating energy balance, but the role of this interaction in bone metabolism is unknown. Using ghrelin receptor and leptin-deficient mice, we show that ghrelin has dual effects on osteoclastogenesis, inhibiting osteoclast progenitors directly and stimulating osteoclastogenesis via a more potent systemic/central pathway. Using mice with combined ghrelin receptor and leptin deficiency, we find that this systemic osteoclastogenic activity is suppressed by leptin, thus balancing the two counterregulatory ghrelin pathways and leading to an unchanged bone structure. With aging, this osteoclastogenic ghrelin pathway is lost, unmasking the direct protective effect of ghrelin on bone structure. In conclusion, we identify a novel regulatory network linking orexigenic and anorectic metabolic factors with bone metabolism that is age dependent.

In situ mechanical behavior of mineral crystals in human cortical bone under compressive load using synchrotron X-ray scattering techniques

It is of great interest to delineate the effect of orientation distribution of mineral crystals on the bulk mechanical behavior of bone. Using a unique synergistic approach combining a progressive loading scheme and synchrotron X-ray scattering techniques, human cortical bone specimens were tested in compression to examine the in situ mechanical behavior of mineral crystals aligned in different orientations. The orientation distribution was quantitatively estimated by measuring the X-ray diffraction intensity from the (002) plane in mineral crystals. In addition, the average longitudinal (c-axis), transverse (a-axis), and shear strains of the subset of mineral crystals aligned in each orientation were determined by measuring the lattice deformation normal to three distinct crystallographic planes (i.e. 002, 310, and 213) in the crystals. The experimental results indicated that the in situ strain and stress of mineral crystals varied with orientations. The normal strain and stress in the longitudinally aligned mineral crystals were markedly greater than those in the transversely oriented crystals, whereas the shear stress reached a maximum for the crystals aligned in ±30° with respect to the loading direction. The maximum principal strain and stress were observed in the mineral crystals oriented along the loading axis, with a similar trend observed in the maximum shear strain and stress. By examining the in situ behavior, the contribution of mineral crystals to load bearing and the bulk behavior of bone are discussed.

Noninvasive imaging of bone microarchitecture

The noninvasive quantification of peripheral compartment-specific bone microarchitecture is feasible with high-resolution peripheral quantitative computed tomography (HR-pQCT) and high-resolution magnetic resonance imaging (HR-MRI). In addition to classic morphometric indices, both techniques provide a suitable basis for virtual biomechanical testing using finite element (FE) analyses. Methodical limitations, morphometric parameter definition, and motion artifacts have to be considered to achieve optimal data interpretation from imaging studies. With increasing availability of in vivo high-resolution bone imaging techniques, special emphasis should be put on quality control including multicenter, cross-site validations. Importantly, conclusions from interventional studies investigating the effects of antiosteoporotic drugs on bone microarchitecture should be drawn with care, ideally involving imaging scientists, translational researchers, and clinicians.

Gender- and region-specific variations of estrogen receptor α and β expression in the growth plate of spine and limb during development and adulthood

Although estrogen action is indispensable for normal bone growth in both genders, the roles of estrogen receptors (ERs) in mediating bone growth are not fully understood. The effects of ER inactivation on bone growth are sex and age dependent, and may differ between the axial and appendicular regions. In this study, the spatial and temporal expression of ERα and β in the tibial and spinal growth plates of the female and male rats during postnatal development was examined to explore the possible mechanisms. The level of mRNA was examined and compared with quantitative real-time PCR. The spatial location was determined by immunohistochemical analysis. The 1-, 4-, 7-, 12- and 16-week age stages correspond to early life, puberty and early adulthood after puberty, respectively. Gender- and region-specific differences in ERα and β expression were shown in the growth plates. Mainly nuclear staining of ERα and β immunoreactivity was demonstrated in the spinal and tibial growth plate chondrocytes for both genders. Moreover, our study indicated significant effect of gender on temporal ERα and β expression and of region on temporal ERα/ERβ expression ratio. However, spatial differences of region-related ERα and β expression were not observed. Gender-related spatial changes were detected only at 16 weeks of both spine and limb growth plates. ERα and β immunoreactivity was detected in the resting, proliferative and prehypertrophic chondrocytes in the early life stage and during puberty. After puberty, ERα expression was mainly located in the late proliferative and hypertrophic chondrocytes in female, whereas the expression still extended from the resting to hypertrophic chondrocytes in males. Gender- and region-specific expression patterns of ERα and β gene might be one possible reason for differences in sex- and region-related body growth phenotypes. Gender, age and region differences should be taken into consideration when the roles of ERs in the growth plate are investigated.

Gender aspects of osteoporosis and bone strength

Although postmenopausal and elderly women are more frequently affected by osteoporosis, men are not protected from the disease. Age-related osteoporosis involves several gender-specific clinical aspects such as disease onset time and different dynamics of bone loss. Men benefit from larger bones and a time-delay of age-related changes in bone density and quality. Moreover, secondary osteoporosis is more common in males than in females. High-resolution peripheral quantitative computed tomography (HR-pQCT) and high-resolution magnetic resonance imaging (HR-MRI) represent novel research tools for a noninvasive quantification of bone microstructure which is of interest for musculoskeletal gender studies. For optimal design of such studies, researchers should be aware of technical pitfalls and site-specificity of bone microstructure.

The evidence for efficacy of osteoporosis treatment in men with primary osteoporosis: a systematic review and meta-analysis of antiresorptive and anabolic treatment in men

Purpose. Fragility fractures in men constitute a major worldwide public health problem with a life-time risk of 13%. It cannot be directly inferred that antiosteoporotic drugs effective in women have the same effect in men. Our aim was to appraise the existing evidence for efficacy of osteoporosis treatment in men. Methods. This study was a systematic review of the published literature on the clinical efficacy of medical osteoporosis therapy in the reduction of fracture risk in men (age > 50 years). Studies included were randomised, placebo-controlled trials of men. Results. Five BMD studies of antiresorptive treatment were included. All studies showed an increase in BMD, but there was only a nonsignificant trend in the reduction of clinical fractures. Three BMD studies of anabolic treatment with teriparatide were also included. These showed a significant mean increase in spine BMD and for vertebral fractures a non-significant trend towards a reduction was seen. Conclusion. The evidence of medical osteoporosis treatment in men is scant and inconclusive due to the lack of prospective RCT studies with fracture prevention as primary end point. So far, all evidence is based on BMD increases in small RCT studies showing BMD increases comparable to those reported in postmenopausal women.

Heterogeneity of biological bone markers in idiopathic male osteoporosis

In men with idiopathic osteoporosis, histomorphometric studies reported both increased resorption and decreased remodeling. We aimed at examine bone remodeling in these patients by biological marker measurement. We compared pre-treatment carboxy-terminal cross-linking telopeptide of type I collagen (CTX) and bone alkaline phosphatase (bALP) levels in 49 men, mean age 59 ± 14 year, with idiopathic osteoporosis with fractures (40 patients) or osteoporosis diagnosed by densitometry (9 patients) with 50 age-matched controls. The influence of baseline remodeling level on alendronate efficacy was studied. Bone remodeling markers (CTX and bALP) did not significantly differ between patients and controls and were correlated in both groups. There was no correlation between these markers, vitamin D and PTH levels. Twenty-one patients underwent repeat densitometry after 1 year of alendronate (70 mg/week). Mean annual BMD increase, spine +4.1 ± 3.9%, and hip +1.5 ± 1.2% showed no correlation with baseline CTX. Bone remodeling is very heterogeneous and formation and resorption remain biologically coupled in both idiopathic male osteoporosis and controls. Baseline remodeling level does not affect the action of alendronate on BMD.

Patterns of treatment in Australian men following fracture

This study aimed to describe treatment initiation rates for men who had recently sustained a fracture. Most (75.9%) men potentially eligible for subsidised treatment at the time of fracture remained untreated even after a subsequent fracture.

INTRODUCTION

This study aimed to describe treatment initiation rates for men who had recently sustained a fracture.

METHODS

The study was conducted as part of the Geelong Osteoporosis Study in south-eastern Australia. Men in the study area who had sustained an incident fracture in the period July 2006 to December 2007 were identified from hospital radiology reports. A self-report questionnaire was sent to eligible participants approximately 12 months after fracture. Respondents were asked for details of medications prescribed for 'osteoporosis/fracture/low bone mass' before and after fracture, and where applicable, reasons for cessation of treatment. We analysed the results for 109 men aged 50 years and older who had sustained fracture in the study period.

RESULTS

Most (75.9%) men potentially eligible for subsidised treatment at the time of fracture remained untreated. Of the 87 men who were untreated, nine had osteoporosis at the hip and/or spine and 29 (26.6%) reported having sustained a low trauma prior fracture.

CONCLUSIONS

Our findings are consistent with previously published data showing low rates of treatment initiation in men eligible for osteoporosis treatment. There appear to be barriers involving participants' and medical practitioners' knowledge, beliefs and attitudes regarding osteoporosis and treatment, as well as in the doctor-patient partnership in osteoporosis management. Establishment of clinical pathways for fracture management beyond orthopaedic care may be one of a range of appropriate responses.

Experience with alendronate treatment for four years among Japanese men with osteoporosis or osteopenia and clinical risk factors for fractures

Purpose

A retrospective study based on a conventional medical practice was performed to evaluate the outcome of alendronate treatment for four years in Japanese men with osteoporosis or osteopenia and clinical risk factors for fractures.

Methods

Twenty-nine Japanese men with osteoporosis or osteopenia and clinical risk factors for fractures (mean age at baseline 61.0 years) who had been treated with alendronate for over four years in our outpatient clinic were studied. Lumbar spine or total hip bone mineral density (BMD) was measured using dual energy x-ray absorptiometry, and urinary levels of cross-linked N-terminal telopeptides of type I collagen (NTX) and serum levels of bone-specific alkaline phosphatase were monitored during the four-year treatment period.

Results

Urinary NTX and serum bone-specific alkaline phosphatase levels decreased (−44.4% at three months and −61.2% at four years, respectively) and lumbar spine and total hip BMD increased (+13.9% and +9.2% at four years, respectively), compared with baseline values. No serious adverse events were observed, including osteonecrosis of the jaw, femoral diaphysis atypical fractures, or atrial fibrillation.

Conclusion

To our knowledge, this is the first report of the outcome of alendronate treatment for four years in Japanese men with an increased risk for fractures. Alendronate suppressed bone turnover and increased lumbar spine and total hip BMD from baseline over the course of the four-year treatment period without causing any severe adverse events in Japanese men with osteoporosis or osteopenia and clinical risk factors for fractures.

Male osteoporosis

Osteoporosis develops in males approximately 10 years later than in females. Low vitamin D is a common problem. Decline in testosterone represents a major cause for osteoporosis in men. Bisphosphonates are the treatment of choice for osteoporosis in older males.

Comparison of the effects of alendronate and alfacalcidol on hip bone mineral density and bone turnover in Japanese men having osteoporosis or osteopenia with clinical risk factors for fractures

PURPOSE

The comparative effects of alendronate and alfacalcidol on bone mineral density (BMD) and bone turnover have already been established in postmenopausal women with osteoporosis. An open-labeled prospective study was conducted to compare the treatment effects of alendronate and alfacalcidol on hip BMD and bone turnover in Japanese men with osteoporosis or osteopenia with clinical risk factors for fractures.

MATERIALS AND METHODS

One hundred twelve men with osteoporosis or osteopenia with clinical risk factors for fractures (mean age: 71.4 years) were randomly divided into two groups of 56 patients each: the alendronate (5 mg daily) and alfacalcidol (1 microg daily) groups. The BMD of the total hip, urinary level of cross-linked N-terminal telopeptides of type I collagen (NTX), and serum levels of bone-specific alkaline phosphatase (BSAP) were measured during the 12-month-treatment period.

RESULTS

Forty-five patients in the alendronate group and 42 patients in the alfacalcidol group completed the trial. Alendronate increased BMD (+2.3% at 12 months) following reductions in the urinary level of NTX (-46.4% at 3 months) and serum level of BSAP (-34.1% at 12 months), while alfacalcidol sustained BMD (-1.9% at 12 months) as well as the urinary level of NTX (+13.2% at 3 months) and serum level of BSAP (+1.8% at 12 months).

CONCLUSION

The present study confirmed that alendronate has better efficacy than alfacalcidol (active control) in increasing hip BMD and reducing bone turnover in Japanese men with osteoporosis or osteopenia with clinical risk factors for fractures.

A new tool to assess the mechanical properties of bone due to collagen degradation

Current clinical tools for evaluating fracture risk focus only on the mineral phase of bone. However, changes in the collagen matrix may affect bone mechanical properties, increasing fracture risk while remaining undetected by conventional screening methods such as dual energy x-ray absorptiometry (DXA) and quantitative ultrasound (QUS). The mechanical response tissue analyzer (MRTA) is a non-invasive, radiation-free potential clinical tool for evaluating fracture risk. The objectives of this study were two-fold: to investigate the ability of the MRTA to detect changes in mechanical properties of bone as a result of treatment with 1 M potassium hydroxide (KOH) and to evaluate the differences between male and female bone in an emu model. DXA, QUS, MRTA and three-point bending measurements were performed on ex vivo emu tibiae before and after KOH treatment. Male and female emu tibiae were endocortically treated with 1 M KOH solution for 1-14 days, resulting in negligible collagen loss (0.05%; by hydroxyproline assay) and overall mass loss (0.5%). Three-point bending and MRTA detected significant changes in modulus between days 1 and 14 of KOH treatment (-18%) while all values measured by DXA and QUS varied by less than 2%. This close correlation between MRTA and three-point bending results support the utility of the MRTA as a clinical tool to predict fracture risk. In addition, the significant reduction in modulus contrasted with the negligible amount of collagen removal from the bone after KOH exposure. As such, the significant changes in bone mechanical properties may be due to partial debonding between the mineral and organic matrix or in situ collagen degradation rather than collagen removal. In terms of sex differences, male emu tibiae had significantly decreased failure stress and increased failure strain and toughness compared to female tibiae with increasing KOH treatment time.

Cortical bone loss in androgen-deficient aged male rats is mainly caused by increased endocortical bone remodeling

INTRODUCTION

Hypogonadism is considered to be one of the major risk factors for osteoporosis in men. Here, we sequentially studied the effects of androgen deficiency on cortical bone in aged orchiectomy (ORX) rats.

MATERIALS AND METHODS

One hundred seventy 13-mo-old male Fischer-344 rats were either ORX or sham-operated. After in vivo fluorochrome labeling, groups of 8-15 SHAM and ORX rats each were killed at 2 wk and 1, 2, 3, 4, 6, and 9 mo after surgery. To examine the effects of testosterone replacement therapy, 9-mo-old ORX rats were supplemented with testosterone undecanoate at a weekly dose of 6 mg/kg for 4 mo. Cortical bone changes in the tibial shaft were monitored by pQCT analysis and by bone histomorphometry.

RESULTS

SHAM rats did not show age-related bone loss at the tibial diaphysis. pQCT analysis and bone histomorphometry showed cortical bone osteopenia in ORX rats, beginning from 2 mo after surgery until the end of the study. Androgen deficiency induced a sustained decrease in periosteal bone formation during the first 4 mo after ORX. However, although periosteal expansion of the tibial shaft tended to be slower in ORX rats compared with SHAM controls, the reduction in total cross-sectional area in ORX animals reached statistical significance only at 4 mo after surgery. The major mechanism for cortical bone loss in aged ORX rats was a progressive expansion of the marrow cavity, which was associated with an initial increase in endocortical eroded perimeter at 1 and 2 mo after surgery, followed by a sustained increase in endocortical bone formation until the end of the study. All these changes were prevented in aged ORX rats receiving testosterone supplementation in an insulin-like growth factor system-independent fashion.

CONCLUSIONS

We conclude that androgen deficiency-induced cortical bone loss in aged, nongrowing rats is mainly caused by augmented endocortical bone remodeling.

Percolation theory relates corticocancellous architecture to mechanical function in vertebrae of inbred mouse strains

Complex corticocancellous skeletal sites such as the vertebra or proximal femur are connected networks of bone capable of transferring mechanical loads. Characterizing these structures as networks may allow us to quantify the load transferring behavior of the emergent system as a function of the connected cortical and trabecular components. By defining the relationship between certain physical bone traits and mechanical load transfer pathways, a clearer picture of the genetic determinants of skeletal fragility can be developed. We tested the hypothesis that the measures provided by network percolation theory will reveal that different combinations of cortical, trabecular, and compositional traits lead to significantly different load transfer pathways within the vertebral bodies among inbred mouse strains. Gross morphologic, micro-architectural, and compositional traits of L5 vertebrae from 15 week old A/J (A), C57BL6/J (B6), and C3H/HeJ (C3H) inbred mice (n=10/strain) were determined using micro-computed tomography. Measures included total cross-sectional area, bone volume fraction, trabecular number, thickness, spacing, cortical area, and tissue mineral density. Two-dimensional coronal sections were converted to network graphs with the cortical shell considered as one highly connected node. Percolation parameters including correlation length (average number of connected nodes between superior and inferior surfaces), chemical length (minimum number of connected nodes between surfaces), and backbone mass (strut number) were measured. Analysis of the topology of the connected bone networks showed that A and B6 mice transfer load through trabecular pathways in the middle of the vertebral body in addition to the cortical shell. C3H mice transfer load primarily through the highly mineralized cortical shell. Thus, the measures provided by percolation theory provide a quantitative approach to study how different combinations of cortical and trabecular traits lead to mechanically functional structures. The data further emphasize the interdependent nature of these physical bone traits suggesting similar genetic variants may affect both trabecular and cortical bone. Therefore, developing a network approach to study corticocancellous architecture during growth should further our understanding of the biological basis of skeletal fragility and, thus, provide novel engineering approaches to studying the genetic basis of fracture risk.

Integrating a gender dimension into osteoporosis and fracture risk research

BACKGROUND

Sex (referring to the strict biological sense) and gender (referring to the sociocultural dimension) are major determinants of health and disease.

OBJECTIVE

This review examines similarities and differences between the sexes in the prevalence of osteoporosis and fractures, bone- and fall-related risk factors for incident fractures, and the possibilities of fracture prevention, as well as gender differences in the perception of osteoporosis.

METHODS

We reviewed recent English-language publications on sex and gender differences in the context of osteoporosis and fracture risk. We refer to several reviews that provide extensive reference lists on the topics discussed.

RESULTS

The incidence of fractures is higher in boys than in girls. The burden of fractures in adults increases with age, and it starts earlier and is higher in adult women than in adult men. With life expectancy increasing, the annual number of fractures is likely to increase substantially. Fractures in adults contribute to increased mortality (more in men than in women), increased morbidity (equal in men and women), and high costs (greater for women than for men). Adult men experience fewer fractures than women do. Men build larger bones with better microarchitecture while they are growing and thereafter have less increase in bone remodeling. Furthermore, they develop bone loss at a later age. Compared with their female counterparts, fewer older men are hypogonadic, and life expectancy is shorter for men than for women. There are multiple reasons for the differences in the incidences of fractures between men and women, related to the many factors associated with both bone and falls that influence fracture risk from the molecular and cellular level to the organ level. Sex hormones play a central and essential role in the physiology of bone by direct and indirect mechanisms (eg, by interfering with the growth hormone and insulin-like growth factor-1 axis). Case-finding strategies to identify patients at highest risk for fractures, including bone densitometry and clinical risk factors, are much better documented at the population level in women than in men. Drug therapies that reduce the risk of a broad spectrum of fractures, even in the short term, are more clearly demonstrated in randomized controlled studies in women than in men. Drug therapy is more widely available for women with osteoporosis,but it is rarely given to men with osteoporosis. Differences in the perception of osteoporosis between men and women are even less well documented.

CONCLUSIONS

In general, osteoporosis is underdiagnosed and undertreated in women but even more so in men, and is related to limits in the patient's and the physician's awareness at all clinical stages, from case finding to compliance with and persistence of therapy. Furthermore, the lay perception of a healthy lifestyle, the level of social isolation, networking within the health care system, and opportunities for screening appear to contribute to gender differences in participating in osteoporosis prevention and therapy. These aspects of health care deserve further attention and research.

Alendronate for the treatment of osteoporosis in men

BACKGROUND

Men have higher rates of osteoporosis and suffer fragility fractures more often than previously believed. Fracture-related morbidity and mortality in men is substantially higher than in women.

OBJECTIVE

To investigate alendronate for treating osteoporosis in men.

METHODS

Search limited to 'men' and 'English'; keywords were 'osteoporosis' or 'bone density' or 'fracture' and 'alendronate'.

RESULTS/CONCLUSIONS

Alendronate is an amino-bisphosphonate with proved efficacy for increasing bone mineral density in men with idiopathic or secondary osteoporosis and has demonstrated an ability to prevent vertebral fractures in men with low bone mass. There are trends for alendronate to decrease the risk of non-vertebral fracture, but larger trials are needed to conclusively establish this benefit. Alendronate is a well-tolerated and comparatively safe drug with an attractive once-a-week dosing regimen.

Osteoporosis in men: are we referring enough for DXA and how?

The aim of the study is to determine the pattern of male referrals to an osteodensitometry unit in a tertiary hospital in UAE. In this study, we reviewed the records of male patients referred for dual X-ray absorptiometry over 9 months since the establishment of the unit. Indications for scanning were categorized into high and medium risk and infrequent causes of osteopenia/osteoporosis. They were ranked according to frequency. The outcome was documented by category and patients were considered normal when they have bone mineral densities (BMD) over 0.82 g/cm(2), osteopenia between 0.60 and 0.82 g/cm(2), and osteoporosis below 0.60 g/cm(2) for hips and lumbar spine. The site with the lowest value was taken as representative of the patient's BMD status. The ages of the patients ranged from 16 to 91 years (mean of 55.2 years). Male referrals made up 8.8% (71/805) over the 9-month period. The number of indications was 83 accounting for 1.16 per patient. Most common reasons were patients on corticosteroid therapy (20.5%), bone rarefaction on radiographs (13%), and fragility fractures (12%). Others included back pain, general aches and pains, querying osteoporosis, and miscellaneous causes that made up 8.5% each. These were followed by immobilization, (6%) arthropathies (6%), excess alcohol intake (3.5%), aging, (2.5%), and hepatorenal disorders (2.5%). A positive family history of osteoporosis, treatment for neoplasia, smoking, and chronic obstructive airway disease (1% each) were the least common reasons for referral. Thirty-five patients (49%) had osteopenia, 16 (22.5%) had osteoporosis, and 20 (28%) were normal. The low referral rate and relatively high normal outcome among men suggest that osteoporosis is still viewed as a disease of females. This aberrant referral pattern, when viewing the majority of indications, reflects an inability to prioritize the reasons for referral. It is prudent, therefore, to instill an awareness of the increasing importance of osteoporosis in men in the minds of the referring clinicians.

The male neck of femur

Fractured neck of femur in elderly is associated with mortality which is reported in literature to vary between 20 and 40%. One of the factors which is suggested to be a risk factor is male sex. We reviewed 83 male necks of femur patients admitted over a period of a year to assess the patient's physical status, influence of co-morbidities, postoperative course and mortality. The in-hospital mortality was 26.5% and 1-year mortality was 44.6%. The in-hospital mortality for female neck of femur patients during the same period was 18%. Increasing age, high ASA category and post-operative chest infections were associated with high peri-operative mortality, and fall sustained in an acute hospital ward was associated with high 1-year mortality in addition to ASA grade and chest infection. Patients who had a chest infection in the post-operative period had in-hospital mortality of 46.2% (P value 0.006) and a 1-year mortality of 73.1% (P value 0.001). Patients who fell in the ward as inpatients under geriatric care had 60% mortality.

Comparison of the effect of alendronate on lumbar bone mineral density and bone turnover in men and postmenopausal women with osteoporosis

The purpose of the present study was to compare the effect of alendronate treatment on lumbar bone mineral density (BMD) and bone turnover in men and postmenopausal women with osteoporosis. Sixty men with primary or secondary osteoporosis and 318 women with postmenopausal osteoporosis were treated with alendronate. The primary end points were lumbar BMD and urinary cross-linked N-terminal telopeptides of type I collagen (NTX) and serum alkaline phosphatase (ALP) levels. The secondary end point was the incidence of vertebral and nonvertebral fractures. Forty-seven (78.3%) men and 254 (79.9%) women who could complete the 12-month trial were analyzed. The mean ages of men and postmenopausal women were 69.1 and 70.4 years, respectively. Both men and postmenopausal women showed higher levels of urinary NTX as compared with normal range of premenopausal women. Alendronate treatment decreased urinary NTX level by 39.2% in men and 45.4% in postmenopausal women at 3 months and serum ALP level by 17.8 and 21.0%, respectively, at 12 months. Following reduction in bone turnover markers, lumbar BMD increased 5.8 and 7.6% in men and postmenopausal women, respectively, at 12 months. Reduction in urinary NTX level and increase in lumbar BMD were smaller in men than in postmenopausal women. The incidence of vertebral and nonvertebral fractures was 10.6 and 8.5%, respectively, in men and 8.3 and 7.5%, respectively, in postmenopausal women, with no significant difference in these incidences between them. These results suggested that alendronate treatment effectively increased lumbar BMD from baseline in men with primary or secondary osteoporosis following reduction in bone turnover, although its efficacy did not appear to be greater than in postmenopausal women with osteoporosis.

Association of quantitative heel ultrasound with history of osteoporotic fractures in elderly men: the ESOPO study

In order to evaluate the usefulness of calcaneal quantitative ultrasound (QUS) in the assessment of male osteoporosis, a cross-sectional, population-based study was performed. A cohort of 4,832 men, randomly selected, community-dwelling, aged 60-80 years and representative of the general older male Italian population was recruited. QUS measurements were assessed in 83 centers distributed all over Italy and equipped with an Achilles device (GE-Lunar, Madison, Wisconsin, USA). All participants were administered a questionnaire covering lifestyle variables and medical history. Low-energy fractures that had occurred since age 50 were recorded. Overall, 43 subjects reported a previous hip fracture and 455 subjects reported other non-spinal fractures. Univariate analysis showed that fractured subjects were older, with a lower level of outdoor physical activity and a more frequent history of prolonged bedridden periods in comparison with unfractured subjects. Men reporting non-spinal fractures showed a higher prevalence of smoking, while no difference was found among groups in anthropometric measures and calcium intake. QUS measurements showed that all QUS parameters were significantly lower in both fracture groups (p<0.001). Multiple logistic regression analysis demonstrated that each SD reduction in QUS measures was associated with an approximate doubling of the risk for hip fracture, independent of age and other clinical variables (broadband ultrasound attenuation [BUA]: odds ratio [OR]=2.24; 95% confidence interval [CI] 1.61-3.08; stiffness index: OR=2.19; CI 1.56-3.11; speed of sound [SOS]: OR=1.71; CI 1.18-3.24) and with an increase of the risk of other non-spinal fractures (BUA: 1.38; CI 1.22-1.59; stiffness index: OR=1.27; CI 1.17-1.38; SOS: OR=1.14; CI 0.96-1.40). It can be concluded that calcaneal QUS measurement is associated with the risk for hip fracture and any non-spinal fractures among a community-dwelling cohort of elderly men. The strength of the association between QUS measurement and fracture is similar to that observed in elderly women.

[Primary and secondary osteoporosis. The important role of internal medicine in its differential diagnosis]

Bone metabolism as an important part of internal medicine is covered by endocrinologists, rheumatologists and nephrologists. Primary osteoporosis is an inheritable metabolic bone disease, which can be strongly modified by lifestyle, ageing and underlying diseases. Chronic inflammatory diseases, disorders of metabolism and nutritional deficits enhance the risk. Secondary osteoporosis is caused by endocrinological disorders and drugs such as glucocorticoids. It is the task of internists to clinically recognise and diagnose prominent individual risk factors for primary osteoporosis and underlying diseases for secondary osteoporosis. The key competence of internal medicine in metabolism, hormone-related disorders, malignant diseases and in handling complex medical treatment modalities represents an indispensable segment of an interdisciplinary network approach in patient care, research and teaching. This network includes orthopaedic surgery, paediatrics and gynaecology in addition to other specialties.

Osteoporosis assessment strategies for male nursing home residents

OBJECTIVES

Twenty-five to thirty percent of hip fractures occur in men, and nursing home residents have a 5-10-fold greater fracture risk than community-dwellers. Osteoporosis prevalence in men in long-term care, however, is poorly defined. Our objectives were to determine the prevalence of osteoporosis, as assessed by peripheral bone mineral density (BMD), in a group of institutionalized veterans, and to determine how many men with low BMD had received a prior diagnosis of osteoporosis.

METHODS

Subjects were residents in a 740-bed skilled nursing facility (78% men). Male residents (n = 103) competent to give informed consent underwent bilateral calcaneal and forearm BMD by dual-energy X-ray absorptiometry (DXA). Prior osteoporosis documentation was sought in medical records.

RESULTS

Twenty percent of veterans (95% confidence interval (CI) 12-28%) exhibited calcaneal osteoporosis (T-score < -2.5), and 62% (CI 52-72%) were osteoporotic at the forearm. Forearm and calcaneal BMD were correlated (r = 0.678, P < 0.001). BMD of the left and right forearm, and of left and right calcaneus, were highly correlated (r = 0.880, P < 0.001 and r = 0.931, P < 0.001, respectively). Documentation of osteoporosis existed for one of 20 men with calcaneal osteoporosis and four of 59 men with forearm osteoporosis.

CONCLUSIONS

Osteoporosis was prevalent but poorly documented in institutionalized veterans. Discordance in T-scores between forearm and heel was similar to that reported in other studies. The broad range of T-scores among subjects suggests that peripheral BMD measurement may be useful for clinical fracture risk stratification. Correlation among skeletal sites indicates that measuring a single site may be practical.

First inventory of resorption lacunae on rods and plates of trabecular bone as observed by scanning electron microscopy

In the present study a novel systematic distribution scheme of resorption lacunae (RL) was applied using scanning electron microscopy. RL, classified as either reticulate patch resorption lacunae (RPR) or as longitudinally extended resorption lacunae (LER) [11, were analyzed and quantified according to their localizations on rods (middle, nodes or both) and plates (central or peripheral) in standardized segments from the femoral head of 24 Caucasian subjects without bone disease. Age and gender variations were explored. No clear gender-related distribution pattern could be detected on plates. On rods of males, however, the distribution of RL tended to be higher at the nodes, but seemed to be more prevalent in the middle or extended from the middle to the nodes of rods in females. Certain other non-conclusive tendencies in relation to age, gender, type of RL and localization were observed.

Analyses of hind leg skeletons in human growth hormone transgenic rats

Growth hormone (GH) is essential in the development and growth of the skeleton and for the maintenance of bone mass and density, and its secretion is known to decline with aging. We have previously produced transgenic rats with low circulating GH that represent several age-associated phenotypes such as obesity, insulin-resistance and leptin-resistance. In the present study, the cross-sectional area, bone mineral density, and strength indexes of the hind leg skeletons of the transgenic rats were examined by an X-ray computed tomography scanning. The mean cross-sectional area of the transgenic rats showed no increase after 2 months old up to 8 months old and the strength indexes were significantly lower than their non-transgenic siblings at all ages examined. The trabecular bone mineral density in the transgenic rats drastically decreased at 8 months old, while the cortical bone mineral density was comparable to the non-transgenic rats, suggesting the onset of osteoporosis at this period. The results obtained in this study indicate that the transgenic rats could be useful model to gain insight into the complex mechanism leading to osteoporosis with aging.

Women's conditions occurring in men: breast cancer, osteoporosis, male menopause, and eating disorders

Each of the four disorders discussed in this article emphasizes its significance in the morbidity and mortality of men. Recent research has improved the ability to identify many of the key risk factors that could predispose men to breast cancer, osteoporosis, male menopause, and eating disorders. There is a significant need for further research into each of these conditions, as most studies have been conducted on women. The myths that these disorders are just a feminist issue can be ignored no longer. Nurses are in a prime position to help men identify and analyze their risks and help them select appropriate prevention and screening strategies to improve their knowledge and quality of life.

Longitudinal association between sex hormone levels, bone loss, and bone turnover in elderly men

Male osteoporosis is an increasingly important health problem. It is known that sex steroid hormones play an important role in regulating bone turnover and bone mass in males as well as in females. However, the exact mechanism of bone loss in men remains unknown. In the present study, 200 elderly men (age range, 55-85 yr) were followed for 4 yr to evaluate the relationships between hormone levels, bone turnover markers, bone mineral density, and rates of bone loss. Femoral and lumbar bone mineral density, bone ultrasound parameters at the os calcis, serum testosterone (T), serum estradiol (E(2)), SHBG levels, and bone turnover markers (urinary crosslaps and bone alkaline phosphatase) were evaluated for each man at enrollment and 4 yr afterward. The free androgen index (FAI) and free estrogen index (FEI) as well as measures of the bioavailable sex hormones [calculated bioavailable E(2) (c-bioE(2)) and T (c-bioT)] were calculated from total hormone levels and SHBG. In the total population, T, c-bioT, c-bioE(2), FAI, and FEI, but not E(2), decreased significantly with age, whereas SHBG increased significantly. Subjects with FEI, c-bioE(2), and E(2) levels below the median showed higher rates of bone loss at the lumbar spine and the femoral neck as well as higher speed-of-sounds decrease at the calcaneus with respect to men with FEI, c-bioE(2), and E(2) levels above the median. Serum bone alkaline phosphatase and urinary crosslaps were significantly higher in men with FEI, c-bioE(2), and E(2) in the lower quartile than in men with FEI, c-bioE(2), and E(2) levels in the higher quartile. No statistically significant differences were observed in relation to T, c-bioT, or FAI levels. Finally, the ratio between E(2) and T, an indirect measure for aromatase activity, increased significantly with age and was higher in normal than in osteoporotic subjects. In conclusion, results from the present study indicate an important role of estrogens, and particularly of the ability to aromatize T to E(2), in the regulation of bone loss and bone metabolism in elderly men.

Standardization of BMD T-Scores in the first five years after the menopause: do femoral neck-equivalent and older normative range T-Scores improve diagnostic agreement?

Calculating T-scores using an older reference population reduces inconsistency between measurement sites when osteoporosis is diagnosed in the elderly. The present analysis in a younger, early postmenopausal cohort examined 5-yr consistency of normalization by local and femoral neck-equivalent T-scores. NHANES (femur) and Hologic (spine and forearm) references were applied to baseline, 1-, 2-, 3-, and 5-yr scans in 925 untreated women in a national cohort study, and alternative local and neck-equivalent scores calculated. The baseline prevalence of osteopenia/osteoporosis was 35.5%/4.1% (spine), 31.0%/1.2% (neck), 31.3%/1.2% (total hip), and 37.2%/2.5% (forearm). It increased to 54.6%/7% by combining sites. The prevalences at 5-yr were 57.2%/12.4% (spine), 51.9%/5.0% (neck), 46.6%/3.7% (total hip), 52.5%/7.4% (forearm), and 77.3%/17.8% (any). A T-score cut-off at the lowest of four sites of -1.65 for osteopenia and -3.37 for osteoporosis was equivalent in patient numbers to T<-1 and T<-2.5 at the femoral neck. The proportion of inconsistently classified subjects decreased from 48% to 42% (p<0.05) with neck-equivalent scores. No improvement remained after 5 yr. Kappa scores did not improve by the use of local or femoral neck scores. In conclusion, adjusted thresholds cannot remove the anatomic discrepancy between T-scores. To overcome this problem, risk-based diagnostic cut-offs must therefore be calculated separately for each measurement site and fracture localization.