Develop a bone mineral density T-score distribution nomograms based on osteoporosis risk factors for middle-aged and older adults.

PURPOSE: This study aimed to understand how age, health status, and lifestyle impact bone mineral density (BMD) in middle-aged and older adults, focusing on predicting osteoporosis risk. METHODS: This study included 2836 participants aged 50-88 from the Health Improvement Program of Bone (HOPE) conducted from 2021 to 2023. We used logistic regression to make a prediction tool. Then checked its accuracy and reliability using receiver operating characteristic (ROC) and calibration curves. RESULTS: Factors like age, body weight, prior fractures, and smoking were independently found to affect BMD T-score distribution in men. In women, age and body weight were identified as independent factors influencing BMD T-score distribution. A nomogram was created to visually illustrate these predictive relationships. CONCLUSIONS: The nomogram proved highly accurate in identifying men aged 50 and above and postmenopausal women based on their BMD T-score distribution, improving clinical decision-making and patient care in osteoporosis evaluation and treatment.

Economic evaluation of four treatment strategies for postmenopausal patients with osteoporosis and a recent fracture in mainland China: a cost-effectiveness analysis.

Postmenopausal patients with osteoporosis who have a recent fracture are at very high risk of fracture, and this study finds that stratified treatment based on fracture risk would be a cost-effective treatment option for this population. PURPOSE: To evaluate the cost-effectiveness of four anti-osteoporosis medications (denosumab, zoledronate, teriparatide, and alendronate) for postmenopausal osteoporotic women in mainland China, using a stratified treatment strategy recommended by the American Association of Clinical Endocrinologists and the American College of Endocrinology (AACE/ACE). METHODS: A microsimulation Markov model was used to compare the cost-effectiveness of the four treatments in postmenopausal osteoporotic patients of different ages (65, 70, 75, and 80 years), with a recent fracture from the Chinese healthcare perspective. The primary outcome was the incremental cost-effectiveness ratio (ICER), which represent the incremental cost per quality-adjusted life-year (QALY) obtained. One-way deterministic sensitivity analysis (DSA) and probabilistic sensitivity analysis (PSA) were performed to assess the robustness of model findings. RESULTS: Alendronate was dominated by denosumab-to-alendronate and zoledronate at all ages examined, indicating that the costs of the two drugs were lower, but QALYs was greater. However, teriparatide-to-alendronate yielded an ICER of $76,432.07/ QALY, compared with alendronate at age 65, which exceeded the pre-determined willingness-to-pay threshold of $37,653/ QALY. The results were similar at other ages. The DSA showed that the most sensitive parameters were drug efficacy for vertebral and wrist fractures, the relative risk of vertebral fractures, and the persistence of the drugs. The PSA showed that zoledronate had a 100% probability of being the most cost-effective treatment, with a willingness-to-pay threshold of $37,653/ QALY. CONCLUSION: Stratified treatment based on very high fracture risk is more cost-effective than conventional pills in mainland China. Among the stratified treatments, zoledronate is the optimal option.

Development of a Nomogram for Predicting Very Low Bone Mineral Density (T-Scores <-3) in the Chinese Population.

PURPOSE: Fragility fractures, the most serious complication of osteoporosis, affect life quality and increase medical expenses and economic burden. Strategies to identify populations with very low bone mineral density (T-scores <-3), indicating very high fracture risk according to the American Association of Clinical Endocrinologists/American College of Endocrinology (AACE/ACE), are necessary to achieve acceptable fracture risk levels. In this study, the characteristics of persons with T-scores <-3 were analyzed in the Chinese population to identify risk factors and develop a nomogram for very low bone mineral density (T-scores <-3) identification. MATERIALS AND METHODS: We conducted a cross-sectional study using the datasets of the Health Improvement Program of Bone (HOPE), with 602 men aged ≥50 years and 482 postmenopausal women. Bone mineral density (BMD) was measured using dual energy X-ray absorptiometry (DXA). Data on clinical risk factors, including age, sex, weight, height, previous fracture, parental hip fracture history, smoking, alcohol intake >3 units/day, glucocorticoid use, rheumatoid arthritis, and secondary osteoporosis were collected. A multivariate logistic regression to evaluate the relationship between the clinical risk factors and very low BMD (T-scores <-3) was conducted. Parameter estimates of the final model were then used to construct a nomogram. RESULTS: Sixty-three of 1084 participants (5.8%) had BMD T-score <-3. In multivariable regression analysis, age (odds ratio [OR] = 1.068, 95% confidence interval [CI]: 1.037-1.099) and weight (OR = 0.863, 95% CI: 0.830-0.897) were significant factors that were associated with very low BMD (T-scores <-3). These variables were the factors considered in developing the nomogram. The area under the receiver operating characteristic (ROC) curve for the model was 0.861. The cut-off value of the ROC curve was 0.080. CONCLUSION: The nomogram can effectively assist clinicians to identify persons with very low BMD (T-scores <-3) and very high fracture risk in the Chinese population.

Epidemiology and management of osteoporosis in the People's Republic of China: current perspectives.

With the progressive aging of the population, osteoporosis has gradually grown into a global health problem for men and women aged 50 years and older because of its consequences in terms of disabilities and fragility fractures. This is especially true in the People's Republic of China, which has the largest population and an increasing proportion of elderly people, as osteoporosis has become a serious challenge to the Chinese government, society, and family. Apart from the fact that all osteoporotic fractures can increase the patient's morbidity, they can also result in fractures of the hip and vertebrae, which are associated with a significantly higher mortality. The cost of osteoporotic fractures, moreover, is a heavy burden on families, society, and even the country, which is likely to increase in the future due, in part, to the improvement in average life expectancy. Therefore, understanding the epidemiology of osteoporosis is essential and is significant for developing strategies to help reduce this problem. In this review, we will summarize the epidemiology of osteoporosis in the People's Republic of China, including the epidemiology of osteoporotic fractures, focusing on preventive methods and the management of osteoporosis, which consist of basic measures and pharmacological treatments.

[Relationship of age-related levels of serum sex hormones with bone mineral density decreasing rate in women].

OBJECTIVE: To explore the relationship between the changes of estrogen, follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels and bone mineral density (BMD) decreasing rate (BDR) at different skeletal regions and examine the effects of hormones levels on BDR. METHODS: An age cross-sectional study was conducted in 694 healthy adult women excluded from diseases and drugs affecting bone metabolism. Their age range was 20-80 years. The serum concentrations of FSH, LH and estradiol (E2) were measured with radioimmunoassay. And BDR was measured with a DXA fan-beam bone densitometer at various skeletal regions including lumbar spine, left hip and left forearm. RESULTS: The serum levels of FSH (r = -0.597 to -0.479, all P < 0.01) and LH r = -0.452 to -0.283, all P < 0.01) were significantly negatively correlated with BDR at various skeletal regions. Meanwhile, the serum level of E2 only had slightly positive correlation with hip and distal forearm (r = 0.077 to 0.122, all P < 0.05). After adjusting age and body mass index (BMI), serum FSH still had markedly negative correlation with BDR at various skeletal regions. However, the correlation coefficients became weak. Multiple line regression stepwise analysis revealed that serum FSH was a negative determinant factor of BDR at various skeletal regions: 20%-32% changes in BDR of various skeletal regions were determined by FSH, while LH only produced very small negative effects (0.6%-0.8%) on BDR of lumbar spine. Serum E2 seemed to be a positive determinant factor of skeletal regions and 2.5%-5.4% changes in BDR were determined by E2. The effects of serum FSH on BDR were approximately 3.8-12.8 folds than those of serum E2. CONCLUSIONS: BDR is correlated with increased FSH in women. The most critical factor for aging-related BDR is FSH in women while a decreased level of estrogen may be secondary.

Early bone mineral density decrease is associated with FSH and LH, not estrogen.

BACKGROUND: It remains unclear whether gonadotropins or estrogen is responsible for early bone mineral density (BMD) decrease in Chinese women. METHODS: A cross-sectional study was conducted on 368 healthy adult women, aged 35-60 years. We measured BMD, calculated BMD decrease rates (BDRs) and assessed serum follicle-stimulating hormone (FSH), luteinizing hormone (LH) and estradiol (E(2)) levels. RESULTS: BDR was significantly negatively correlated with serum FSH (r=-0.429 to -0.622, all p=0.000) and LH (r=-0.359 to -0.526, all p=0.000). After adjustment for age and body mass index, the negative correlations of serum FSH and LH with BDR persisted, but there was no overall correlation between serum E(2) and BDR. Multiple linear stepwise regression analysis suggested that serum FSH is a negative determinant of BDR. Serum E(2) seems to be a positive determinant of BDR in a few parts of the skeleton. CONCLUSIONS: The decrease of BMD during the menopause is associated with FSH and LH levels, rather than E(2) in Chinese women.

Taurine suppresses osteoblastic differentiation of aortic valve interstitial cells induced by beta-glycerophosphate disodium, dexamethasone and ascorbic acid via the ERK pathway.

Aortic valve calcification (AVC) is an active process characterized by osteoblastic differentiation of the aortic valve interstitial cells (AVICs). Taurine is a free ß-amino acid and plays important physiological roles including protective effect of cardiovascular events. To evaluate the possible role of taurine in AVC, we isolated human AVICs from patients with type A dissection without leaflet disease. We demonstrated that the cultured AVICs express SM α-actin, vimentin and taurine transporter (TAUT), but not CD31, SM-myosin or desmin. We also established the osteoblastic differentiation model of the AVICs induced by pro-calcific medium (PCM) containing ß-glycerophosphate disodium, dexamethasone and ascorbic acid in vitro. The results showed that taurine attenuated the PCM-induced osteoblastic differentiation of AVICs by decreasing the alkaline phosphate (ALP) activity/expression and the expression of the core binding factor α1 (Cbfα1) in a dose-dependent manner (reaching the maximum protective effect at 10 mM), and taurine (10 mM) inhibited the mineralization level of AVICs in the form of calcium content significantly. Furthermore, taurine activated the extracellular signal-regulated protein kinase (ERK) pathway via TAUT, and the inhibitor of ERK (PD98059) abolished the effect of taurine on both ALP activity/expression and Cbfα1 expression. These results suggested that taurine could inhibit osteoblastic differentiation of AVIC via the ERK pathway.

RANKL is a downstream mediator for insulin-induced osteoblastic differentiation of vascular smooth muscle cells.

Several reports have shown that circulating insulin level is positively correlated with arterial calcification; however, the relationship between insulin and arterial calcification remains controversial and the mechanism involved is still unclear. We used calcifying vascular smooth muscle cells (CVSMCs), a specific subpopulation of vascular smooth muscle cells that could spontaneously express osteoblastic phenotype genes and form calcification nodules, to investigate the effect of insulin on osteoblastic differentiation of CVSMCs and the cell signals involved. Our experiments demonstrated that insulin could promote alkaline phosphatase (ALP) activity, osteocalcin expression and the formation of mineralized nodules in CVSMCs. Suppression of receptor activator of nuclear factor κB ligand (RANKL) with small interfering RNA (siRNA) abolished the insulin-induced ALP activity. Insulin induced the activation of extracellular signal-regulated kinase (ERK)1/2, mitogen-activated protein kinase (MAPK) and RAC-alpha serine/threonine-protein kinase (Akt). Furthermore, pretreatment of human osteoblasts with the ERK1/2 inhibitor PD98059, but not the phosphoinositide 3-kinase (PI3K) inhibitor, LY294002, or the Akt inhibitor, 1L-6-hydroxymethyl-chiro-inositol 2-(R)-2-O-methyl-3-O-octadecylcarbonate (HIMO), abolished the insulin-induced RANKL secretion and blocked the promoting effect of insulin on ALP activities of CVSMCs. Recombinant RANKL protein recovered the ALP activities decreased by RANKL siRNA in insulin-stimulated CVSMCs. These data demonstrated that insulin could promote osteoblastic differentiation of CVSMCs by increased RANKL expression through ERK1/2 activation, but not PI3K/Akt activation.

Omentin-1 attenuates arterial calcification and bone loss in osteoprotegerin-deficient mice by inhibition of RANKL expression.

AIMS: Omentin-1 (also known as intelectin-1) is a recently identified visceral adipose tissue-derived cytokine that is inversely related to obesity. Our previous study showed that omentin-1 inhibits osteoblastic differentiation of calcifying vascular smooth muscle cells (CVSMCs) in vitro. This study was undertaken to investigate the effects of omentin-1 on arterial calcification and bone metabolism in vivo. METHODS AND RESULTS: In vitro, omentin-1 stimulated production of osteoprotegerin (OPG) and inhibited production of receptor activator for nuclear factor κB ligand (RANKL) in both CVSMCs and osteoblasts. In vivo, adenovirus-mediated over-expression of omentin-1 attenuated arterial calcification and bone loss in OPG(-/-) mice. All these in vitro and in vivo actions were abrogated by blockade of the PI3K-Akt signalling pathway. Furthermore, omentin-1 reduced serum levels of RANKL, tartarate-resistant acid phosphatase-5b and osteocalcin, all of which are increased dramatically in OPG(-/-) mice. CONCLUSION: These data suggest that omentin-1 ameliorates arterial calcification and bone loss in vivo through the regulation of the RANK signalling pathway.

Estrogen receptor α36 mediates a bone-sparing effect of 17ß-estrodiol in postmenopausal women.

Recently, a membrane-based estrogen receptor (ER), ER-α36, was identified and cloned that transduces membrane-initiated estrogen signaling such as activation of the mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) signaling pathway. Here we show that the postmenopausal level of estradiol (E2) induces mitogenic, antiapoptotic, and antiosteogenic effects and proapoptotic effects in postmenopausal osteoblasts and osteoclasts with high levels of ER-α36 expression, respectively. We also found that ER-α36 mediated the effects of postmenopausal-level E(2) on proliferation, apoptosis, and differentiation of osteoblasts through transient activation of the MAPK/ERK pathway, whereas ER-α36-mediated postmenopausal-level E(2) induces apoptosis of osteoclasts through prolonged activation of the MAPK/ERK pathway with the involvement of reactive oxygen species. We also show that the levels of ER-α36 expression in bone are positively associated with bone mineral density but negatively associated with bone biochemical markers in postmenopausal women. Thus the higher levels of ER-α36 expression are required for preserving bone mass in postmenopausal and menopausal women who become osteoporotic if ER-α36-mediated activities are dysregulated.

OPG knockout mouse teeth display reduced alveolar bone mass and hypermineralization in enamel and dentin.

Recent studies showed that local injection or upregulation of OPG gene would result in early temporal retardation of tooth development. It was assumed that this retardation might cause defective tooth mineralization and pulp formation as the long-term effects. However, since those OPG treatments were transient, any possible long-term effects of OPG addition could not be assessed previously. In the present study, a high-resolution microCT was used to evaluate the long-term effect of OPG gene deprivation on the mineralization and morphology of mouse tooth. Our results showed that the mineralization of alveolar bone in OPG(-/-) mouse tooth was decreased while those of enamel and dentin were increased, compared with the wild-type (WT) group. The labial and lingual dentin thicknesses of OPG(-/-) group were significantly higher and with larger area in enamel and dentin than those of WT group. The size of pulp chamber was also substantially decreased in OPG(-/-) mouse incisor. Different responses in mineralization and morphogenesis to OPG gene deprivation were found between bone and tooth. These effects may be independent of the early odontogenesis, and further studies are warranted to investigate the molecular mechanism of the effect of OPG gene expression on bone formation and later tooth development.

A novel microRNA targeting HDAC5 regulates osteoblast differentiation in mice and contributes to primary osteoporosis in humans.

MicroRNAs (miRNAs) interfere with translation of specific target mRNAs and are thought to thereby regulate many cellular processes. Recent studies have suggested that miRNAs might play a role in osteoblast differentiation and bone formation. Here, we identify a new miRNA (miR-2861) in primary mouse osteoblasts that promotes osteoblast differentiation by repressing histone deacetylase 5 (HDAC5) expression at the post-transcriptional level. miR-2861 was found to be transcribed in ST2 stromal cells during bone morphogenetic protein 2-induced (BMP2-induced) osteogenesis, and overexpression of miR-2861 enhanced BMP2-induced osteoblastogenesis, whereas inhibition of miR-2861 expression attenuated it. HDAC5, an enhancer of runt-related transcription factor 2 (Runx2) degradation, was confirmed to be a target of miR-2861. In vivo silencing of miR-2861 in mice reduced Runx2 protein expression, inhibited bone formation, and decreased bone mass. Importantly, miR-2861 was found to be conserved in humans, and a homozygous mutation in pre-miR-2861 that blocked expression of miR-2861 was shown to cause primary osteoporosis in 2 related adolescents. Consistent with the mouse data, HDAC5 levels were increased and Runx2 levels decreased in bone samples from the 2 affected individuals. Thus, our studies show that miR-2861 plays an important physiological role in osteoblast differentiation and contributes to osteoporosis via its effect on osteoblasts.

Quantitative associations between osteocyte density and biomechanics, microcrack and microstructure in OVX rats vertebral trabeculae.

Osteocytes actively regulate bone modeling and remodeling, direct skeletal mineralization, and regulate calcium/phosphate homeostasis and extracellular matrix metabolism; yet the specific role of osteocytes in maintaining bone structural integrity and strength is unknown. Studies have shown that the density of osteocytes decreases with age and estrogen deficiency, as seen in postmenopausal women. Here, we examined the relationships between osteocyte density and the related variables, including biomechanics, bone mineral density, microcrack and microstructure of vertebral trabeculae, in ovariectomized rats. We found that osteocyte density correlated with some of the parameters that determine the biomechanical quality of bone. Our findings suggest that osteocytes could play a crucial role in maintaining the mechanical quality of bone, and osteocyte density could be considered as an alternative index in assessing bone quality.