Osteoporosis diagnosis in men: the T-score controversy revisited

Preoperative Osteoporosis Is Associated with Increased Healthcare Utilization and Compromised Pain and Function Improvement after Primary Total Hip Arthroplasty: A Prospective Cohort Analysis

BACKGROUND

Osteoporosis (OP) has been linked to complications after total hip arthroplasty (THA), but its impact on healthcare utilization and patient-reported outcomes remains unclear. This study aimed to evaluate the association between: 1) pre-THA OP and healthcare utilization as well as patient-reported pain and function outcome measures; and 2) Dual Energy X-ray Absorptiometry (DEXA) scan-based T-scores and the aforementioned outcomes.

METHODS

A retrospective analysis of prospectively collected data of primary THA (2015 to 2018) was performed (n = 5,321) from a validated academic institutional database of a large North American tertiary health care system; of which 4,074 (76.6%) completed one-year follow-up. Outcomes included prolonged length of stay [LOS] > 3 days, discharge disposition, 90-day readmission, and one-year reoperation, as well as Hip Disability and Osteoarthritis Outcome Score (HOOS]) Pain, HOOS-function (PS), and minimal clinically important difference thresholds (MCID), and satisfaction.

RESULTS

The prevalence of OP pre-THA was 56.9%, of which 39.8% were not prescribed OP medications and 15.3% had a DEXA scan. Compared to those who did not have OP, those who had OP were independently associated with higher odds of prolonged LOS, non-home discharge, 90-day readmission, and 1-year reoperation (P < 0.005). Furthermore, they had significantly higher odds of failing to achieve MCID (odds ratio (OR): 1.41 (95% confidence interval (CI): 1.06 to 1.89)) for HOOS-PS and satisfaction (OR: 1.5 (95% CI: 1.16 to 1.93)) at 1-year. Higher T-scores were associated with lower odds of prolonged LOS, non-home discharge, failure to achieve MCID in HOOS-Pain, and HOOS-PS.

CONCLUSION

Over half of patients had OP, however, only 15.3% of patients had a DEXA scan prior to THA. Patients who had OP were at higher risk of prolonged LOS, non-home discharge, 90-day readmission, and one-year reoperation in addition to poor pain/function improvement and dissatisfaction one year after THA.

[Osteoporosis-Definition, risk assessment, diagnosis, prevention and treatment (update 2024) : Guidelines of the Austrian Society for Bone and Mineral Research]

BACKGROUND

Austria is among the countries with the highest incidence and prevalence of osteoporotic fractures worldwide. Guidelines for the prevention and management of osteoporosis were first published in 2010 under the auspices of the then Federation of Austrian Social Security Institutions and updated in 2017. The present comprehensively updated guidelines of the Austrian Society for Bone and Mineral Research are aimed at physicians of all specialties as well as decision makers and institutions in the Austrian healthcare system. The aim of these guidelines is to strengthen and improve the quality of medical care of patients with osteoporosis and osteoporotic fractures in Austria.

METHODS

These evidence-based recommendations were compiled taking randomized controlled trials, systematic reviews and meta-analyses as well as European and international reference guidelines published before 1 June 2023 into consideration. The grading of recommendations used ("conditional" and "strong") are based on the strength of the evidence. The evidence levels used mutual conversions of SIGN (1++ to 3) to NOGG criteria (Ia to IV).

RESULTS

The guidelines include all aspects associated with osteoporosis and osteoporotic fractures, such as secondary causes, prevention, diagnosis, estimation of the 10-year fracture risk using FRAX®, determination of Austria-specific FRAX®-based intervention thresholds, drug-based and non-drug-based treatment options and treatment monitoring. Recommendations for the office-based setting and decision makers and institutions in the Austrian healthcare system consider structured care models and options for osteoporosis-specific screening.

CONCLUSION

The guidelines present comprehensive, evidence-based information and instructions for the treatment of osteoporosis. It is expected that the quality of medical care for patients with this clinical picture will be substantially improved at all levels of the Austrian healthcare system.

Opportunistic use of chest low-dose computed tomography (LDCT) imaging for low bone mineral density and osteoporosis screening: cutoff thresholds for the attenuation values of the lower thoracic and upper lumbar vertebrae

Background

Osteoporosis remains substantially underdiagnosed and undertreated worldwide. Chest low-dose computed tomography (LDCT) may provide a valuable and popular opportunity for osteoporosis screening. This study sought to evaluate the feasibility of the screening of low bone mineral density (BMD) and osteoporosis with mean attenuation values of the lower thoracic compared to upper lumbar vertebrae. The cutoff thresholds of the mean attenuation values in Hounsfield units (HU) were derived to facilitate implementation of opportunistic screening using chest LDCT.

Methods

The participants aged 30 years or older who underwent chest LDCT and quantitative computed tomography (QCT) examinations from August 2018 to October 2020 in our hospital were consecutively included in this retrospective study. A region of interest (ROI) was placed in the trabecular bone of each vertebral body to measure the HU values. The correlations of mean HU values of lower thoracic (T11-T12) and upper lumbar (L1-L2) vertebrae with age and lumbar BMD obtained with QCT were performed using the Pearson correlation coefficient, respectively. The area under the curve (AUC) of the receiver operator characteristic (ROC) curve was generated to determine the cutoff thresholds for distinguishing low BMD from normal and osteoporosis from non-osteoporosis.

Results

A total of 1,112 participants were included in the final study cohort (743 men and 369 women, mean age 58.2±8.9 years; range, 32-88 years). The mean HU values of T11-T12 and L1-L2 were significantly different among 3 QCT-defined BMD categories of osteoporosis, osteopenia, and normal (P<0.001). The differences in HU values between T11-T12 and L1-L2 in each category of bone status were statistically significant (P<0.001). The mean HU values of T11-T12 (r=-0.453, P<0.001) and L1-L2 (r=-0.498, P<0.001) had negative correlations with age. Positive correlations were observed between the mean HU values of T11-T12 (r=0.872, P<0.001) and L1-L2 (r=0.899, P<0.001) with BMD. The optimal cutoff thresholds for distinguishing low BMD from normal were average T11-T12 ≤157 HU [AUC =0.941, 95% confidence interval (CI): 0.925-0.954, P<0.001] and L1-L2 ≤138 HU (AUC =0.950, 95% CI: 0.935-0.962, P<0.001), as well as distinguishing osteoporosis from non-osteoporosis were average T11-T12 ≤125 HU (AUC =0.960, 95% CI: 0.947-0.971, P<0.001) and L1-L2 ≤107 HU (AUC =0.961, 95% CI: 0.948-0.972, P<0.001). There was no significant difference between the AUC values of T11-T12 and L1-L2 for low BMD (P=0.07) and osteoporosis (P=0.92) screening.

Conclusions

We have conducted a study on low BMD and osteoporosis screening using mean attenuation values of lower thoracic and upper lumbar vertebrae. Assessment of mean attenuation values of T11-T12 and L1-L2 can be used interchangeably for low BMD and osteoporosis screening using chest LDCT, and their cutoff thresholds were established.

Opportunistic screening for osteoporosis using routine clinical care computed tomography brain studies

OBJECTIVE

Osteoporosis and falls are both prevalent in the elderly, and CT brain (CTB) is frequently performed post head-strike. We aim to validate the relationship between frontal bone density (Hounsfield unit) from routine CTB and bone mineral density from dual-energy X-ray absorptiometry (DEXA) scan for opportunistic osteoporosis screening.

MATERIALS AND METHODS

Patients who had a non-contrast CTB followed by a DEXA scan in the subsequent year were included in this multi-center retrospective study. The relationship between frontal bone density on CT and femoral neck T-score on DEXA was examined using ANOVA, Pearson's correlation, and receiver operating curve (ROC) analysis. Sensitivity, specificity, negative and positive predictive values, and area under the curve (AUC) were calculated.

RESULTS

Three hundred twenty-six patients (205 females and 121 males) were analyzed. ANOVA analysis showed that frontal bone density was lower in patients with DEXA-defined osteoporosis (p < 0.001), while Pearson's correlation analysis demonstrated a fair correlation with femoral neck T-score (r = 0.3, p < 0.001). On subgroup analysis, these were true in females but not in males. On ROC analysis, frontal bone density weakly predicted osteoporosis (AUC 0.6, 95% CI 0.5-0.7) with no optimal threshold identified. HU < 610 was highly specific (87.5%) but poorly sensitive (18.9%). HU > 1200 in females had a strong negative predictive value for osteoporosis (92.6%, 95% CI 87.1-98.1%).

CONCLUSION

Frontal bone density from routine CTB is significantly different between females with and without osteoporosis, but not between males. However, frontal bone density was a weak predictor for DEXA-defined osteoporosis. Further research is required to determine the role of CTB in opportunistic osteoporosis screening.

QbD-driven development and characterization of superparamagnetic iron oxide nanoparticles (SPIONS) of a bone-targeting peptide for early detection of osteoporosis

Osteoporosis is a metabolic disorder that leads to deterioration of bones. The major challenges confronting osteoporosis therapy include early-stage detection and regular disease monitoring. The present studies employed D-aspartic acid octapeptide (-D-Asp-)8 as bone-targeting peptide for evaluating osteoporosis manifestation, and superparamagnetic iron oxide nanoparticles (SPIONs) as nanocarriers for MRI-aided diagnosis. Thermal decomposition technique was employed to synthesize SPIONs, followed by surface-functionalization with hydrophilic ligands. Failure mode effect analysis and factor screening studies were performed to identify concentrations of SPIONs and ligand as critical material attributes, and systematic optimization was subsequently conducted employing face-centered cubic design. The optimum formulation was delineated using desirability function, and design space demarcated with 178.70 nm as hydrodynamic particle size, -24.40 mV as zeta potential, and 99.89 % as hydrophilic iron content as critical quality attributes. XRD patterns ratified lattice structure and SQUID studies corroborated superparamagnetic properties of hydrophilic SPIONs. Bioconjugation of (-D-Asp-)8 with SPIONs (1:1) was confirmed using UV spectroscopy, FTIR and NMR studies. Cell line studies indicated successful targeting of SPIONs to MG-63 human osteoblasts, ratifying enormous bone-targeting and safety potential of peptide-tethered SPIONs as MRI probes. In vivo MRI imaging studies in rats showcased promising contrast ability and safety of peptide-conjugated SPIONs.

Structural differences contributing to sex-specific associations between FN BMD and whole-bone strength for adult White women and men

Hip areal BMD (aBMD) is widely used to identify individuals with increased fracture risk. Low aBMD indicates low strength, but this association differs by sex with men showing greater strength for a given aBMD than women. To better understand the structural basis giving rise to this sex-specific discrepancy, cadaveric proximal femurs from White female and male donors were imaged using nano-CT and loaded in a sideways fall configuration to assess strength. FN pseudoDXA images were generated to identify associations among structure, aBMD, and strength that differ by sex. Strength correlated significantly with pseudoDXA aBMD for females (R2 = 0.468, P < .001) and males (R2 = 0.393, P < .001), but the elevations (y-intercepts) of the linear regressions differed between sexes (P < .001). Male proximal femurs were 1045 N stronger than females for a given pseudoDXA aBMD. However, strength correlated with pseudoDXA BMC for females (R2 = 0.433, P < .001) and males (R2 = 0.443, P < .001) but without significant slope (P = .431) or elevation (P = .058) differences. Dividing pseudoDXA BMC by FN-width, total cross-sectional area, or FN-volume led to significantly different associations between strength and the size-adjusted BMC measures for women and men. Three structural differences were identified that differentially affected aBMD and strength for women and men: First, men had more bone mass per unit volume than women; second, different cross-sectional shapes resulted in larger proportions of bone mass orthogonal to the DXA image for men than women; and third, men and women had different proportions of cortical and trabecular bone relative to BMC. Thus, the proximal femurs of women were not smaller versions of men but were constructed in fundamentally different manners. Dividing BMC by a bone size measure was responsible for the sex-specific associations between hip aBMD and strength. Thus, a new approach for adjusting measures of bone mass for bone size and stature is warranted.

Reference-Class Problems Are Real: Health-Adjusted Reference Classes and Low Bone Mineral Density

Elselijn Kingma argues that Christopher Boorse's biostatistical theory (the BST) does not show how the reference classes it uses are objective and naturalistic. Recently, philosophers of medicine have attempted to rebut Kingma's concerns. I argue that these rebuttals are theoretically unconvincing, and that there are clear examples of physicians adjusting their reference classes according to their prior knowledge of health and disease. I focus on the use of age-adjusted reference classes to diagnose low bone mineral density in children. In addition to using the BST's age, sex, and species, physicians also choose to use other factors to define reference classes, such as pubertal status, bone age, body size, and muscle mass. I show that physicians calibrate the reference classes they use according to their prior knowledge of health and disease. Reference classes are also chosen for pragmatic reasons, such as to predict fragility fractures.

East Asians' T-scores for the diagnosis of osteoporosis should be calculated using ethnicity- and gender-specific BMD reference ranges: justifications

The 2013 ISCD consensus recommended a Caucasian female reference database for T-score calculation in men, which says "A uniform Caucasian (non-race adjusted) female reference database should be used to calculate T-scores for men of all ethnic groups." However, this statement was recommended for the US population, and no position was taken with respect to BMD reference data or ethnicity matching outside of the USA. In East Asia, currently, a Japanese BMD reference database is universally adopted in Japan for clinical DXA diagnosis, while both local BMD and Caucasian BMD reference databases are in use in Mainland China, South Korea, Taiwan, and Singapore. In this article, we argue that an ethnicity- and gender-specific BMD database should be used for T-score calculations for East Asians, and we list the justifications why we advocate so. Use of a Caucasian BMD reference database leads to systematically lower T-scores for East Asians and an overestimation of the prevalence of osteoporosis. Using a female BMD reference database to calculate T-scores for male patients leads to higher T-score values and an underestimation of the prevalence of osteoporosis. Epidemiological evidence does not support using a female BMD reference database to calculate T-scores for men. We also note that BMD reference databases collected in Asia should be critically evaluated for their quality.

Which Bone Mineral Density Measure Offers a More Reliable Prediction of Mechanical Complications in Adult Spinal Deformity Surgery: Hounsfield Units or DEXA Scan?

OBJECTIVE

In patients undergoing adult spinal deformity (ASD) surgery, we sought to: (1) determine the relationship between dual-energy x-ray absorptiometry (DEXA)-measured bone mineral density (BMD), T-scores, and Hounsfield units (HU), and (2) compare the ability of DEXA-measured BMD, T-scores, and HU to predict mechanical complications and reoperations.

METHODS

A single-institution retrospective cohort study was undertaken for cases from 2013 to 2017.

INCLUSION CRITERIA

≥5-level-fusion, sagittal/coronal deformity, and 2-year follow-up. Multivariable regression controlled for age, body mass index, receiving anabolic medications, and postoperative sagittal vertical axis and pelvic-incidence lumbar-lordosis mismatch. A subanalysis was performed for osteopenic patients (-1 < T-score < -2).

RESULTS

Of 145 patients undergoing ASD surgery, 72 (49.6%) had both preoperative DEXA and computed tomography scans. Mean DEXA-measured BMD was 0.91 ± 0.52 g/cm2, mean T-score was -1.61 ± 1.03, and mean HU was 153.5 ± 52.8. While no correlation was found between DEXA-measured BMD and HU (r = 0.17, P = 0.144), T-score and HU had a weakly positive correlation (r = 0.31, P = 0.007). Mechanical complications occurred in 48 (66.7%) patients, including 27 (37.5%) proximal junctional kyphosis (PJK), 1 (1.4%) distal junctional kyphosis, 5 (6.9%) implant failure, 30 (41.7%) rod fracture/pseudarthrosis, 42 (58.3%) reoperations, and 16 (22.2%) reoperations due to PJK. No association was found between DEXA-measured BMD or T-scores with mechanical complications or reoperations. While univariate regression showed a significant association between lower HU and PJK (OR 0.98, 95%CI 0.97-0.99, P = 0.011), the significance was lost after multivariable analysis. When considering osteopenic patients (n = 37), only DEXA-measured BMD was an independent risk factor for PJK (OR 0.01, 95%CI 0.00-0.09, P = 0.017), with a threshold of 0.82 g/cm2 (AUC 0.70, 95%CI 0.53-0.84, P = 0.019).

CONCLUSIONS

Poor correlation was found between the 3 BMD modalities. DEXA-measured BMD may be superior to T-scores and HU in predicting PJK among patients with osteopenia with a threshold of BMD <0.82 g/cm2.

Identification of mouse soleus muscle proteins altered in response to changes in gravity loading

Gravity-dependent physical processes strongly affect the ability of elderly people to maintain musculoskeletal health by reducing muscle atrophy and increasing bone mineral density, thereby increasing quality of life. A need therefore exists to identify molecules in the musculoskeletal system that are responsive to gravitational loading and to establish an objective indicator for the maintenance of healthy musculoskeletal systems. Here, we performed an integrated assessment of the results of soleus muscle proteomic analyses in three model mouse experiments under different gravity environments (hypergravity, hindlimb unloading, and spaceflight). Myl6b, Gpd1, Fbp2, Pvalb, and Actn3 were shown to be gravity-responsive muscle proteins, and alterations in the levels of these proteins indicated changes in muscle fiber type to slow-twitch type due to gravity loading. In addition, immunoblotting and enzyme-linked immunosorbent assays revealed that Pvalb levels in the sera of hindlimb-unloaded mice and osteoporosis patients were higher than in control subjects, suggesting that Pvalb levels might be useful to objectively evaluate soleus muscle atrophy and bone loss.

The relation between dietary quality and healthy eating index with bone mineral density in osteoporosis: a case-control study

BACKGROUND

In this study, we aimed to illustrate the association between the Healthy Eating Index (HEI) and Dietary Quality Index (DQI) with bone mineral density (BMD) among postmenopausal Iranian women with osteoporosis compared to the healthy control.

METHODS

In the current case-control study, 131 postmenopausal women with osteoporosis and 131 healthy postmenopausal women participated. Dual-energy X-ray absorptiometry was used to assess the lumbar vertebrae and femoral neck BMD. The subjects completed a validated food frequency questionnaire (FFQ), and then HEI and DQI were calculated based on the FFQ data. Crude and adjusted multivariable logistic regression was used to assess the relation between HEI and DQI with the odds of the femoral and lumbar BMD.

RESULTS

According to the results, participants in the last tertile of HEI were more likely to have higher femoral and lumbar BMD in the crude model (odds ratio (OR) = 0.38; 95% confidence interval (CI): 0.20-0.71 and OR = 0.20; 95% CI: 0.10-0.40, respectively) and also in the adjusted model (OR = 0.40; 95% CI: 0.20-0.78 and OR = 0.20; 95% CI: 0.10-0.41, respectively). Also, in terms of DQI-I, participants in the last tertile were more likely to have higher femoral and lumbar BMD in the crude model (OR = 0.23; 95% CI: 0.12-0.45 and OR = 0.29; 95% CI: 0.15-0.55, respectively) and also in the adjusted model (OR = 0.29; 95% CI: 0.14-0.58 and OR = 0.34; 95% CI: 0.17-0.67, respectively).

CONCLUSIONS

The results of the current study supported the hypothesis that high-quality diets with healthy patterns can be clinically effective in maintaining bone health. Thus, recommendations regarding the consumption of nutrient-rich food groups in a healthy diet can serve as a practical non-pharmacological strategy against osteoporosis.

Quantitative ultrasound of the calcaneus (QUS): A valuable tool in the identification of patients with non-metastatic prostate cancer requiring screening for osteoporosis

Non-metastatic prostate cancer (PCa) patients are at increased risk for osteoporosis and fractures mainly due to androgen deprivation therapy (ADT)-associated hypogonadism, but this remains largely underdiagnosed and untreated. In this study, we examine the value of pre-screening calcaneal QUS in identifying patients who should be referred for screening for osteoporosis using dual-energy X-Ray absorptiometry (DXA). In a single-center retrospective cross-sectional cohort study, we analysed data on DXA and calcaneal QUS measurements systematically collected between 2011 and 2013 in all non-metastatic PCa patients attending our Uro-Oncological Clinic at the Leiden University Medical Center. Receiver operating characteristic curves were used to assess the positive (PPV) and negative (NPV) predictive values of QUS T-scores of 0, -1.0, and - 1.8 in identifying DXA-diagnosed osteoporosis (T-scores ≤ - 2.5 and ≤ -2) at lumbar spine and/or femoral neck. Complete sets of data were available in 256 patients, median age 70.9 (53.6-89.5) years; 93.0 % had received local treatment, 84.4 % with additional ADT. Prevalence of osteoporosis and osteopenia was respectively 10.5 % and 53 %. Mean QUS T-score was -0.54 ± 1.58. Whereas PPV at any QUS T-score was <25 %, precluding the use of QUS as surrogate for DXA in screening for osteoporosis, QUS T-scores of -1.0 to 0.0 had a NPV of ≥94.5 % for DXA T-scores ≤ 2.5 and ≤ -2 at any site, confidently identifying patients least likely to have osteoporosis, thereby significantly reducing the number of patients requiring DXA screening for diagnosing osteoporosis by up to two-third. Osteoporosis screening is a significant unmet need in non-metastatic prostate cancer patients treated with ADT, and QUS may represent a valuable alternative pre-screening strategy to overcome logistics, time demands, and economic barriers encountered with current strategies for osteoporosis screening in these patients.

Summary

Osteoporosis and associated increased fracture risk are common in non-metastatic prostate carcinoma, mainly due to androgen deprivation therapy, but these often remain underdiagnosed and untreated. We demonstrate that QUS is a safe, less costly pre-screen tool that reduces by up to two-third the number of patients requiring referral for DXA for osteoporosis screening.

Fracture risk and assessment in adults with cancer

Individuals with cancer face unique risk factors for osteoporosis and fractures. Clinicians must consider the additive effects of cancer-specific factors, including treatment-induced bone loss, and premorbid fracture risk, utilizing FRAX score and bone mineral densitometry when available. Pharmacologic therapy should be offered as per cancer-specific guidelines, when available, or local general osteoporosis guidelines informed by clinical judgment and patient preferences. Our objective was to review and summarize the epidemiologic burden of osteoporotic fracture risk and fracture risk assessment in adults with cancer, and recommended treatment thresholds for cancer treatment-induced bone loss, with specific focus on breast, prostate, thyroid, gynecological, multiple myeloma, and hematopoietic stem cell transplant. This narrative review was informed by PubMed searches to July 25, 2022, that combined terms for cancer, stem cell transplantation, fracture, bone mineral density (BMD), trabecular bone score, FRAX, Garvan nomogram or fracture risk calculator, QFracture, prediction, and risk factors. The literature informs that cancer can impact bone health in numerous ways, leading to both systemic and localized decreases in BMD. Many cancer treatments can have detrimental effects on bone health. In particular, hormone deprivation therapies for hormone-responsive cancers such as breast cancer and prostate cancer, and hematopoietic stem cell transplant for hematologic malignancies, adversely affect bone turnover, resulting in osteoporosis and fractures. Surgical treatments such as hysterectomy with bilateral salpingo-oophorectomy for gynecological cancers can also lead to deleterious effects on bone health. Radiation therapy is well documented to cause localized bone loss and fractures. Few studies have validated the use of fracture risk prediction tools in the cancer population. Guidelines on cancer-specific treatment thresholds are limited, and major knowledge gaps still exist in fracture risk and fracture risk assessment in patients with cancer. Despite the limitations of current knowledge on fracture risk assessment and treatment thresholds in patients with cancer, clinicians must consider the additive effects of bone damaging factors to which these patients are exposed and their premorbid fracture risk profile. Pharmacologic treatment should be offered as per cancer-specific guidelines when available, or per local general osteoporosis guidelines, in accordance with clinical judgment and patient preferences.

Risk of osteoporosis in testicular germ cell tumour survivors: A systematic review of the literature

Context

Testicular germ cell tumour (TGCT) survivors are potentially at risk of developing osteoporosis, because of increased risk for disturbed bone remodelling associated with hypogonadism and anti-cancer treatment. A number of studies show bone loss and increased fracture risk in TGCT survivors, but data are scarce. There are no clinical guidelines or recommendations issued to address skeletal health in this group of patients potentially at high risk for osteoporosis.

Objective

To conduct a systematic review of available literature addressing bone health in TGCT patients. Subgroup analysis was performed to identify risk factors for bone loss and increased fracture risk.

Evidence Acquisition

Relevant databases, including MEDLINE, Embase and the Cochrane Library, including all English written comparative studies addressing bone health in TGCT patients, were searched up to December 2021 and a narrative synthesis was undertaken. Risk of bias (RoB) was assessed using Cochrane ROBINS-I tool.

Evidence Synthesis

Ten studies (eight cross-sectional and two longitudinal), recruiting a total of 1997 unique TGCT patients, were identified and included in the analysis. Bone health was reported in various ways in different studies, and subgroups were defined heterogeneously, resulting in a widely varying prevalence of osteoporosis of up to 73.2% of patients. Six studies reported low BMD associated with higher luteinizing hormone levels and one study showed a correlation between follow up duration and bone loss.

Conclusions

TGCT survivors are at risk of developing osteoporosis and sustaining fragility fractures. Chemotherapy, pituitary-gonadal axis dysfunction and ageing are key risk factors, although available data are scarce. With increasing survival of TGCT patients, a clear unmet need has been identified to systematically evaluate and monitor skeletal health in larger numbers of survivors in order to develop best clinical practice guidelines to manage the insidious but potentially preventable and treatable skeletal complications of TGCT.

Osteoporosis and risk of fracture: reference class problems are real

Elselijn Kingma argues that Christopher Boorse's biostatistical theory does not show how the reference classes it uses-namely, age groups of a sex of a species-are objective and naturalistic. Boorse has replied that this objection is of no concern, because there are no examples of clinicians' choosing to use reference classes other than the ones he suggests. Boorse argues that clinicians use the reference classes they do because these reflect the natural classes of organisms to which their patients belong. Drawing on a thorough exploration of how the disease osteoporosis is defined in adults, I argue that clinicians do indeed make choices about which reference classes to use in diagnosis. Clinicians use young adult reference classes to diagnose osteoporosis in elderly patients. They also use young female reference classes to diagnose osteoporosis in elderly males. Clinicians adjust their reference classes so that the diagnosis of osteoporosis reflects a person's risk of sustaining a fragility fracture. The ethical intuition that people with the same risk of fracture should receive the same diagnosis overwhelms the naturalistic intuition that reference classes should reflect natural classes of organisms of uniform functional design. Clinicians construct a variety of reference class types, including pathological reference classes and epidemiological population-specific reference classes, to serve this ethical intuition. I show how clinicians use several reference classes at once so that they can more accurately predict risk of fracture. Ultimately, the reference classes chosen and used in medical practice are quite different from those proposed in naturalistic philosophy of medicine.

Bone health in ageing men

Osteoporosis does not only affect postmenopausal women, but also ageing men. The burden of disease is projected to increase with higher life expectancy both in females and males. Importantly, osteoporotic men remain more often undiagnosed and untreated compared to women. Sex steroid deficiency is associated with bone loss and increased fracture risk, and circulating sex steroid levels have been shown to be associated both with bone mineral density and fracture risk in elderly men. However, in contrast to postmenopausal osteoporosis, the contribution of relatively small decrease of circulating sex steroid concentrations in the ageing male to the development of osteoporosis and related fractures, is probably only minor. In this review we provide several clinical and preclinical arguments in favor of a 'bone threshold' for occurrence of hypogonadal osteoporosis, corresponding to a grade of sex steroid deficiency that in general will not occur in many elderly men. Testosterone replacement therapy has been shown to increase bone mineral density in men, however data in osteoporotic ageing males are scarce, and evidence on fracture risk reduction is lacking. We conclude that testosterone replacement therapy should not be used as a sole bone-specific treatment in osteoporotic elderly men.

Activation of farnesoid X receptor signaling by geniposidic acid promotes osteogenesis

BACKGROUND

New targets and strategies are urgently needed for the identification and development of anabolic drugs for osteoporosis. Farnesoid X receptor (FXR) is a promising novel therapeutic target for bone metabolism diseases. Although used clinically, FXR agonists have obvious side effects; therefore, the development of new FXR agonists for the treatment of osteoporosis would be welcomed. Geniposidic acid (GPA) is a bioactive compound extracted from Eucommiae cortex, which is used for treating arthritis, osteoporotic fractures, and hypertension. However, the therapeutic effects of GPA against osteoporosis remain underexplored.

PURPOSE

This study aims to reveal the potential osteogenic effects of FXR and to explore the effect of GPA on bone formation, osteoporosis treatment, and FXR signaling.

STUDY DESIGN & METHODS

The role of FXR in promoting bone formation was evaluated in Fxr knockout (Fxr^-/-) mice and cell models. GPA activation of FXR was evaluated by molecular docking and luciferase reporter gene assays. Thirty female C57BL/6J mice were randomly assigned into a sham operation group (Sham) and four ovariectomized (OVX) groups (n=6 each) and were treated with vehicle or different doses of GPA (25, 50, and 100 mg/kg/day). The therapeutic effect of GPA on osteoporosis was systematically analyzed by performing bone histomorphometry and measuring serum biochemical parameters, and the molecular mechanism was also evaluated. Furthermore, the action of GPA in Fxr^-/- mice was evaluated to investigate its dependency on FXR in promoting bone formation and treating osteoporosis.

RESULTS

We found that FXR was highly expressed in bone tissues and enriched in osteoblasts. Notably, deletion of FXR significantly reduced the bone formation rate and bone mass of the Fxr^-/- mice compared with wild-type mice. Furthermore, using a high throughput drug screening strategy based on fluorescent reporter genes, we found that GPA functions as a natural agonist of FXR. We confirmed the activities of GPA on FXR activation and osteogenesis in both osteoblast differentiation models and OVX-induced osteoporosis models. We revealed that GPA strongly promotes bone formation by activating FXR/RUNX2 signaling. Moreover, the osteoporotic therapeutic effect of GPA was abolished in Fxr^-/- mice.

CONCLUSION

This study demonstrated that FXR is a promising target for treating osteoporosis and that GPA promotes bone formation in OVX-induced osteoporosis by activating FXR signaling. These findings provide novel insight into the mechanism by which GPA promotes bone formation and more evidence for its application in the treatment of osteoporosis.

Screening for osteoporosis using L1 vertebral density on abdominal CT in an Australian population

AIM

To assess the utility of osteoporosis screening using abdominal computed tomography (CT) versus dual-energy X-ray absorptiometry (DXA) T-scores as the reference.

MATERIALS AND METHODS

Patients ≥30 years undergoing abdominal CT and DXA within 12 months were assessed retrospectively. Bone mineral density (BMD) was measured using axial CT attenuation at L1, correlating with DXA T-scores. Sensitivity, specificity, area under the curve (AUC), and odds ratio (OR) were calculated.

RESULTS

The study cohort comprised 407 CT-DXA pairs (58.2% women). The prevalence of osteoporosis was 11.8%. L1 density and T-score were significantly correlated in both women (r=0.35, p<0.001) and men (r=0.15, p=0.04). The AUC to distinguish osteoporosis from osteopenia and normal BMD was 0.64 (95% CI: 0.56-0.71). In women, a threshold of 190 HU detected T-scores ≤ -2.5 with a negative predictive value (NPV) of 94.4% (OR=4.4, p<0.01). In the entire cohort, a threshold of 180 HU detected T-scores ≤ -2.5 with a NPV of 96.2% (OR=4.7, p<0.01).

CONCLUSIONS

CT L1 attenuation correlates with L1 DXA T-scores. Density values < 190 and 180 HU increased the probability of an osteoporosis diagnosis in Australian women and the overall cohort, respectively. Opportunistic screening for osteoporosis using abdominal CT is feasible, enabling identification of at-risk subjects for formal DXA imaging, thereby improving treatment initiation and reducing fracture risk.

UK clinical guideline for the prevention and treatment of osteoporosis

The National Osteoporosis Guideline Group (NOGG) has revised the UK guideline for the assessment and management of osteoporosis and the prevention of fragility fractures in postmenopausal women, and men age 50 years and older. Accredited by NICE, this guideline is relevant for all healthcare professionals involved in osteoporosis management.

INTRODUCTION

The UK National Osteoporosis Guideline Group (NOGG) first produced a guideline on the prevention and treatment of osteoporosis in 2008, with updates in 2013 and 2017. This paper presents a major update of the guideline, the scope of which is to review the assessment and management of osteoporosis and the prevention of fragility fractures in postmenopausal women, and men age 50 years and older.

METHODS

Where available, systematic reviews, meta-analyses and randomised controlled trials were used to provide the evidence base. Conclusions and recommendations were systematically graded according to the strength of the available evidence.

RESULTS

Review of the evidence and recommendations are provided for the diagnosis of osteoporosis, fracture-risk assessment and intervention thresholds, management of vertebral fractures, non-pharmacological and pharmacological treatments, including duration and monitoring of anti-resorptive therapy, glucocorticoid-induced osteoporosis, and models of care for fracture prevention. Recommendations are made for training; service leads and commissioners of healthcare; and for review criteria for audit and quality improvement.

CONCLUSION

The guideline, which has received accreditation from the National Institute of Health and Care Excellence (NICE), provides a comprehensive overview of the assessment and management of osteoporosis for all healthcare professionals involved in its management. This position paper has been endorsed by the International Osteoporosis Foundation and by the European Society for the Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases.

Bibliometric analysis of global research trends on male osteoporosis: a neglected field deserves more attention

We analyzed the knowledge structure, current status, and future directions of 3243 publications on male osteoporosis by employing bibliometric analysis. Our results indicated that Osteoporosis International was the most influential journal in this field. And the study of epidemiology and risk factors has been recognized as a hot research topic in recent years. This study also calls for more attention to be given on male osteoporosis research.

INTRODUCTION

Male osteoporosis is increasing as a serious health problem worldwide with the aging of population. However, a comprehensive understanding of the current status and future trends in this field is lacking to date. The goal of the present study was to summarize and visualize the knowledge framework, research hotspots, and emerging trends of male osteoporosis research based on the bibliometric method.

METHODS

Scientific publications regarding male osteoporosis from 1998 to 2020 were downloaded from the SCIE database. VOSviewer, CiteSpace, and online bibliometric website were used for this study. The main analyses include cooperative relationships between countries/institutions/authors, co-citation analysis of authors/journals, and co-occurrence analysis of keywords/subject categories, as well as analyses on keyword/reference bursts.

RESULTS

A total of 3243 publications with 128,751 citations were identified. Despite experiencing a period of increase in the number of publications, incentives for conducting male osteoporosis research seem to have decreased during recent years. The USA has the most prominent contributions, as reflected by most publications and the highest H-index value. Oregon Health and Science University was the most prolific institution within this domain. The most influential academic journal was Osteoporosis International. Keywords were categorized into four clusters: basic research, epidemiology and risk factors, diagnostic studies, treatment and fracture prevention. Burst keyword detection suggested that the following research directions including "obesity," "zoledronic acid," "DXA," "inflammation," "fall," "microarchitecture," and "sarcopenia" remain research hotspots in the near future and deserve our further attention.

CONCLUSIONS

This is the first bibliometric analysis that provides a comprehensive overview of male osteoporosis research, which may provide helpful references for investigators to further explore hot issues in this field.

Description of Normative Spine TBS Data for Men and Women in Mexican Population

Trabecular Bone Score (TBS) has proven its usefulness to improve areal Bone Mineral Density in diagnosing fracture risk and bone status evaluation. For it to be better interpreted, local reference values are recommended to account for population differences and, if possible, both in women and men, the former being scarcer. Using TBS, we reanalyzed data obtained from the Mexican population included in the Latin American Vertebral Osteoporosis Study and the Mexican Vertebral Study in men that included a random probability sample of 408 women and 414 men aged 50 and older without fractures. Data was used to obtain reference curves in such a population. Mean TBS in women ranged from an average of 1.359 ± 0.118 standard deviation (SD) 50 to 59 and decreased down to 1.211 ± 0.128 SD in women 80 and above. In men ranged from 1.382 ± 0.116 SD in the first group down to 1.315 ± 0.118 SD in the latter with little differences in age groups. Mean values in women are lower than previously suggested cutoff points to establish microarchitecture status using TBS: 1.350 and above normal, 1.200 to 1.349 partially degraded and 1.199 and below, degraded. Our TBS data have the strength of being a random sample drawn from the population, although limited in its extent to one city in Mexico. The means and curves may be used to diagnose bone status with better sensibility and specificity, although these values are yet to be evaluated.

Comparison of Vertebral and Femoral Strength Between White and Asian Adults Using Finite Element Analysis of Computed Tomography Scans

Given non-optimal testing rates for dual-energy X-ray absorptiometry (DXA) and the high use of computed tomography (CT) in some Asian countries, biomechanical computed tomography analysis (BCT)-based bone strength testing, which utilizes previously taken clinical CT scans, may improve osteoporosis testing rates. However, an understanding of ethnic differences in such bone strength measurements between Whites and Asians is lacking, which is an obstacle to clinical interpretation. Using previously taken CT and DXA scans, we analyzed bone strength and bone mineral density (BMD) at the hip and spine in two sex- and age-matched community-based cohorts, aged 40 to 80 years: Whites (Rochester, MN, USA) and Koreans (Seoul, South Korea). For both the spine and femur, the age dependence of bone strength was similar for both groups, White (n = 371; women n = 202, 54.5%) and Korean (n = 396; women n = 199, 50.3%). For both sexes, mean spine strength did not differ between groups, but femur strength was 9% to 14% higher in Whites (p ≤ 0.001), an effect that became non-significant after weight adjustment (p = 0.375). For Koreans of both sexes, the fragile bone strength thresholds for classifying osteoporosis, when derived from regional DXA BMD T-score references, equaled the clinically validated thresholds for Whites (in women and men, femoral strength, 3000 N and 3500 N; vertebral strength 4500 N and 6500 N, respectively). Using these thresholds, classifications for osteoporosis for Koreans based on bone strength versus based on DXA BMD T-scores were consistent (89.1% to 94.4% agreement) at both the hip and spine and for both sexes. The BCT-based, clinically validated bone strength thresholds for Whites also applied to Koreans, which may facilitate clinical interpretation of CT-based bone strength measurements for Koreans. © 2020 American Society for Bone and Mineral Research (ASBMR).

Primary osteoporosis in men: an unmet medical need

Osteoporosis is a skeletal disease characterized by loss of bone strength and increased risk of fractures. Even though fracture prevalence is higher in women, fractures also constitute a significant public health issue in older men. Men are screened less and more frequently undertreated than female patients. It is the goal of this review, to summarize updated information about the current understanding of pathophysiology and clinical aspects of diagnosis and treatment of osteoporosis in men.

A New 1,25 Dihydroxy Vitamin D Analog with Strong Bone Anabolic Activity in OVX Rats with Little or no Bone Resorptive Activity

A new 1α,25-dihydroxy vitamin D₃ analog (2-methylene-22(E)-(24R)-22-dehydro-1α,24,25-trihydroxy-19-norvitamin D₃ or WT-51) has been tested as a possible therapeutic for osteoporosis. It is 1/10th as active as 1,25(OH)₂ D₃ in binding affinity for the vitamin D receptor but is at least 200 times more active than 1,25(OH)₂ D₃ and equal to that of 2MD (2-methylene-19-nor-(20S)-1α,25(OH)₂ D₃ , an analog previously tested in postmenopausal women), in supporting bone formation by isolated osteoblasts in culture. However, in contrast to 2MD, it is virtually inactive on bone resorption in vivo. WT-51 markedly increased bone mass (lumbar and femur) in ovariectomized (OVX) female rats. Further, bone strength tested by the three-point bending system is significantly increased by WT-51. Thus, WT-51 is an attractive candidate for the treatment of postmenopausal osteoporosis. © 2019 American Society for Bone and Mineral Research.

Osteoporosis screening using computed tomography for men with prostate cancer: results of a prospective study

We performed a prospective study using both FRAX and computed tomography to screen for osteoporosis in men undergoing radiation for prostate cancer. We found that implementing routine computed tomography (CT)-based screening was feasible in the setting of a prospective study, but the yield of osteoporosis identification was low in this population.

PURPOSE

Men with prostate cancer (PCa) are at increased risk of hip fracture for multiple reasons. Estimation of hip fracture risk with the FRAX tool is currently recommended, but FRAX alone may not identify a portion of men with osteoporosis. We hypothesized that adding bone mineral density (BMD) screening using CT to FRAX is feasible and would identify more men with osteoporosis.

METHODS

Men with PCa scheduled to undergo CT simulation for radiation treatment were enrolled in a single-arm prospective study. The mean attenuation of the mid-L5 vertebral body trabecular bone (L5_CT) was calculated on a single slice using the radiation simulation CT scan. The 10-year risk of hip fracture was calculated using the FRAX tool. Dual energy X-ray absorptiometry (DXA) was performed for men whose L5_CT measurement was less than 130 Hounsfield units (HU).

RESULTS

A total of 98 eligible men were enrolled and underwent FRAX and CT screening. The median 10-year risk of hip fracture was 1.1% and exceeded 3% in 16 cases; the median L5_CT was 162.28 HU (range 55.6-526.1 HU). DXA scan was completed in 15 men who had L5_CT < 130 HU but 10-year calculated hip fracture risk < 3%, 1 of whom was found to have osteoporosis (T-score ≤ -2.5).

CONCLUSIONS

Implementing CT-based BMD screening was feasible in the setting of a prospective study for men receiving radiation for PCa, but fewer cases than anticipated of osteoporosis were identified.

Opportunistic Osteoporosis Screening at Routine Abdominal and Thoracic CT: Normative L1 Trabecular Attenuation Values in More than 20 000 Adults

Background Abdominal and thoracic CT provide a valuable opportunity for osteoporosis screening regardless of the clinical indication for imaging. Purpose To establish reference normative ranges for first lumbar vertebra (L1) trabecular attenuation values across all adult ages to measure bone mineral density (BMD) at routine CT. Materials and Methods Reference data were constructed from 20 374 abdominal and/or thoracic CT examinations performed at 120 kV. Data were derived from adults (mean age, 60 years ± 12 [standard deviation]; 56.1% [11 428 of 20 374] women). CT examinations were performed with (n = 4263) or without (n = 16 111) intravenous contrast agent administration for a variety of unrelated clinical indications between 2000 and 2018. L1 Hounsfield unit measurement was obtained either with a customized automated tool (n = 11 270) or manually by individual readers (n = 9104). The effects of patient age, sex, contrast agent, and manual region-of-interest versus fully automated L1 Hounsfield unit measurement were assessed using multivariable logistic regression analysis. Results Mean L1 attenuation decreased linearly with age at a rate of 2.5 HU per year, averaging 226 HU ± 44 for patients younger than 30 years and 89 HU ± 38 for patients 90 years or older. Women had a higher mean L1 attenuation compared with men (P < .008) until menopause, after which both groups had similar values. Administration of intravenous contrast agent resulted in negligible differences in mean L1 attenuation values except in patients younger than 40 years. The fully automated method resulted in measurements that were average 21 HU higher compared with manual measurement (P < .004); at intrapatient subanalysis, this difference was related to the level of transverse measurement used (midvertebra vs off-midline level). Conclusion Normative ranges of L1 vertebra trabecular attenuation were established across all adult ages, and these can serve as a quick reference at routine CT to identify adults with low bone mineral density who are at risk for osteoporosis. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Smith in this issue.

CONSENSUS STATEMENT BY THE AMERICAN ASSOCIATION OF CLINICAL ENDOCRINOLOGISTS AND AMERICAN COLLEGE OF ENDOCRINOLOGY ON THE QUALITY OF DXA SCANS AND REPORTS

OBJECTIVE

High-quality dual-energy X-ray absorptiometry (DXA) scans are necessary for accurate diagnosis of osteoporosis and monitoring of therapy; however, DXA scan reports may contain errors that cause confusion about diagnosis and treatment. This American Association of Clinical Endocrinologists/American College of Endocrinology consensus statement was generated to draw attention to many common technical problems affecting DXA report conclusions and provide guidance on how to address them to ensure that patients receive appropriate osteoporosis care.

METHODS

The DXA Writing Committee developed a consensus based on discussion and evaluation of available literature related to osteoporosis and osteodensitometry.

RESULTS

Technical errors may include errors in scan acquisition and/or analysis, leading to incorrect diagnosis and reporting of change over time. Although the International Society for Clinical Densitometry advocates training for technologists and medical interpreters to help eliminate these problems, many lack skill in this technology. Suspicion that reports are wrong arises when clinical history is not compatible with scan interpretation (e.g., dramatic increase/decrease in a short period of time; declines in previously stable bone density after years of treatment), when different scanners are used, or when inconsistent anatomic sites are used for monitoring the response to therapy. Understanding the concept of least significant change will minimize erroneous conclusions about changes in bone density.

CONCLUSION

Clinicians must develop the skills to differentiate technical problems, which confound reports, from real biological changes. We recommend that clinicians review actual scan images and data, instead of relying solely on the impression of the report, to pinpoint errors and accurately interpret DXA scan images.

ABBREVIATIONS

AACE = American Association of Clinical Endocrinologists; BMC = bone mineral content; BMD = bone mineral density; DXA = dual-energy X-ray absorptiometry; ISCD = International Society for Clinical Densitometry; LSC = least significant change; TBS = trabecular bone score; WHO = World Health Organization.

Consensus document on osteoporosis in males

OBJECTIVE

To provide practical recommendations to assess and treat osteoporosis in males.

PARTICIPANTS

Members of the Bone Metabolism Working Group of the Spanish Society of Endocrinology.

METHODS

Recommendations were formulated using the GRADE system (Grading of Recommendations, Assessment, Development, and Evaluation) to describe both the strength of recommendations and the quality of evidence. A systematic search was made in Medline (PubMed) using the following associated terms: «osteoporosis», «men», «fractures», «bone mineral density», «treatment», «hypogonadism», and «prostate cancer». Papers in English and Spanish with publication date before 30 August 2017 were included. Current evidence for each disease was reviewed by 2group members. Finally, recommendations were discussed in a meeting of the working group.

CONCLUSIONS

The document provides evidence-based practical recommendations for diagnosis, assessment, and management of osteoporosis in men and special situations such as hypogonadism and prostate cancer.

UK clinical guideline for the prevention and treatment of osteoporosis

INTRODUCTION

In 2008, the UK National Osteoporosis Guideline Group (NOGG) produced a guideline on the prevention and treatment of osteoporosis, with an update in 2013. This paper presents a major update of the guideline, the scope of which is to review the assessment and management of osteoporosis and the prevention of fragility fractures in postmenopausal women and men age 50 years or over.

METHODS

Where available, systematic reviews, meta-analyses and randomised controlled trials were used to provide the evidence base. Conclusions and recommendations were systematically graded according to the strength of the available evidence.

RESULTS

Review of the evidence and recommendations are provided for the diagnosis of osteoporosis, fracture-risk assessment, lifestyle measures and pharmacological interventions, duration and monitoring of bisphosphonate therapy, glucocorticoid-induced osteoporosis, osteoporosis in men, postfracture care and intervention thresholds.

CONCLUSION

The guideline, which has received accreditation from the National Institute of Health and Care Excellence (NICE), provides a comprehensive overview of the assessment and management of osteoporosis for all healthcare professionals who are involved in its management.

The prevention of fragility fractures in patients with non-metastatic prostate cancer: a position statement by the international osteoporosis foundation

Androgen deprivation therapy is commonly employed for the treatment of non-metastatic prostate cancer as primary or adjuvant treatment. The skeleton is greatly compromised in men with prostate cancer during androgen deprivation therapy because of the lack of androgens and estrogens, which are trophic factors for bone. Men receiving androgen deprivation therapy sustain variable degrees of bone loss with an increased risk of fragility fractures. Several bone antiresorptive agents have been tested in randomized controlled trials in these patients. Oral bisphosphonates, such as alendronate and risedronate, and intravenous bisphosphonates, such as pamidronate and zoledronic acid, have been shown to increase bone density and decrease the risk of fractures in men receiving androgen deprivation therapy. Denosumab, a fully monoclonal antibody that inhibits osteoclastic-mediated bone resorption, is also effective in increasing bone mineral density and reducing fracture rates in these patients. The assessment of fracture risk, T-score and/or the evaluation of prevalent fragility fractures are mandatory for the selection of patients who will benefit from antiresorptive therapy. In the future, new agents modulating bone turnover and skeletal muscle metabolism will be available for testing in these subjects.

Profilin1 is expressed in osteocytes and regulates cell shape and migration

Osteocytes are the most abundant cells in bone and regulate bone metabolism in coordination with osteoblasts and osteoclasts. However, the molecules that control osteocytes are still incompletely understood. Profilin1 is an actin-binding protein that is involved in actin polymerization. Osteocytes possess characteristic dendritic process formed based on actin cytoskeleton. Here, we examined the expression of profilin1 and its function in osteocytes. Profilin1 mRNA was expressed in osteocytic MLO-Y4 cells and its levels were gradually increased along with the time in culture. With regard to functional aspect, knockdown of profilin1 by siRNA enhanced BMP-induced increase in alkaline phosphatase expression levels in MLO-Y4 cells. Profilin1 knockdown suppressed the levels of dendritic processes and migration of MLO-Y4 cells. Since aging causes an increase in ROS in the body, we further examined the effects of hydrogen peroxide on the expression of profilin1. Hydrogen peroxide treatment increased the levels of profilin1 mRNA in MLO-Y4 cells in contrast to the decline in alkaline phosphatase. Profilin1 was expressed not only in MLO-Y4cells but also in the primary cultures of osteocytes. Importantly, profilin1 mRNA levels in primary cultures of osteocytes were higher than those in primary cultures of osteoblasts. To examine in vivo role of profilin1 in osteocytes, profilin1 was conditionally knocked out by using DMP1-cre and profilin1 floxed mice. This conditional deletion of profilin1 specifically in osteocytes resulted in reduction in the levels of bone volume and bone mineral density. These data indicate that profilin1 is expressed in osteocytes and regulates cell shape, migration and bone mass.

SOXC Genes and the Control of Skeletogenesis

The SOXC group of transcription factors, composed of SOX4, SOX11, and SOX12, has evolved to fulfill key functions in cell fate determination. Expressed in many types of progenitor/stem cells, including skeletal progenitors, SOXC proteins potentiate pathways critical for cell survival and differentiation. As skeletogenesis unfolds, SOXC proteins ensure cartilage primordia delineation by amplifying canonical WNT signaling and antagonizing the chondrogenic action of SOX9 in perichondrium and presumptive articular joint cells. They then ensure skeletal elongation by inducing growth plate formation via enabling non-canonical WNT signaling. Human studies have associated SOX4 with bone mineral density and fracture risk in osteoporotic patients, and SOX11 with Coffin-Siris, a syndrome that includes skeletal dysmorphism. Meanwhile, in vitro and mouse studies have suggested important cell-autonomous roles for SOXC proteins in osteoblastogenesis. We here review current knowledge and gaps in understanding of SOXC protein functions, with an emphasis on the skeleton and possible links to osteoporosis.

Osteoporosis and Low Bone Mineral Density in Men with Testosterone Deficiency Syndrome

INTRODUCTION

Testosterone deficiency syndrome (TDS) is a risk factor for low bone mineral density (BMD) and osteoporosis. Knowledge of the relationship between TDS and bone health, as well as the practical aspects of how to diagnose and treat low BMD, is therefore of practical importance to sexual medicine practitioners.

AIM

The aim of this study was to review the physiologic basis and clinical evidence of the relationship between TDS and bone health; and to provide a practical, evidence-based algorithm for the diagnosis and management of low BMD in men with TDS.

METHODS

Method used was a review of relevant publications in PubMed.

MAIN OUTCOME MEASURES

Pathophysiology of low BMD in TDS, morbidity, and mortality of osteoporosis in men, association between TDS and osteoporosis, indications for dual X-ray absorptiometry (DXA) scanning in TDS, evidence for testosterone replacement therapy (TRT) in men with osteoporosis, treatment for osteoporosis in the setting of TDS.

RESULTS

Sex hormones play a pleomorphic role in maintenance of BMD. TDS is associated with increased risk of osteoporosis and osteopenia, both of which contribute to morbidity and mortality in men. DXA scanning is indicated in men older than 50 years with TDS, and in younger men with longstanding TDS. Men with TDS and osteoporosis should be treated with anti-osteoporotic agents and TRT should be highly considered. Men with osteopenia should be stratified by fracture risk. Those at high risk should be treated with anti-osteoporotic agents with strong consideration of TRT; while those at low risk should be strongly considered for TRT, which has a beneficial effect on BMD.

CONCLUSION

Low BMD is a prevalent and treatable cause of morbidity and mortality in men with TDS. Utilization of a practical, evidence-based approach to diagnosis and treatment of low BMD in men with TDS enables sexual medicine practitioners to make a meaningful impact on patient quality of life and longevity. Gaffney CD, Pagano MJ, Kuker AP, Stember DS, and Stahl PJ. Osteoporosis and low bone mineral density in men with testosterone deficiency syndrome.