Deteriorated bone microarchitecture caused by sympathetic overstimulation in pheochromocytoma and paraganglioma

PURPOSE

Despite the potentially destructive effect of sympathetic activity on bone metabolism, its impact on bone microarchitecture, a key determinant of bone quality, has not been thoroughly investigated. This study aims to evaluate the impact of sympathetic activity on bone microarchitecture and bone strength in patients with pheochromocytoma and paraganglioma (PPGL).

METHODS

A cross-sectional study was conducted in 38 PPGL patients (15 males and 23 females). Bone turnover markers serum procollagen type 1 N-terminal propeptide (P1NP) and β-carboxy-terminal crosslinked telopeptide of type 1 collagen (β-CTX) were measured. 24-h urinary adrenaline (24hUE) and 24-h urinary norepinephrine levels (24hUNE) were measured to indicate sympathetic activity. High-resolution peripheral quantitative computed tomography (HR-pQCT) was conducted to evaluate bone microarchitecture in PPGL patients and 76 age-, sex-matched healthy controls (30 males and 46 females). Areal bone mineral density (aBMD) was measured by dual-energy X-ray absorptiometry (DXA) simultaneously.

RESULTS

PPGL patients had a higher level of β-CTX. HR-pQCT assessment revealed that PPGL patients had notably thinner and more sparse trabecular bone (decreased trabecular number and thickness with increased trabecular separation), significantly decreased volume BMD (vBMD), and bone strength at both the radius and tibia compared with healthy controls. The deterioration of Tt.vBMD, Tb.Sp, and Tb.1/N.SD was more pronounced in postmenopausal patients compared with the premenopausal subjects. Moreover, subjects in the highest 24hUNE quartile (Q4) showed markedly lower Tb.N and higher Tb.Sp and Tb.1/N.SD at the tibia than those in the lowest quartile (Q1). Age-related bone loss was also exacerbated in PPGL patients to a certain extent.

CONCLUSIONS

PPGL patients had significantly deteriorated bone microarchitecture and strength, especially in the trabecular bone, with an increased bone resorption rate. Our findings provide clinical evidence that sympathetic overstimulation may serve as a secondary cause of osteoporosis, especially in subjects with increased sympathetic activity.

Cysteine and homocysteine can be exploited by GPX4 in ferroptosis inhibition independent of GSH synthesis

Ferroptosis is inhibited by glutathione peroxidase 4 (GPX4), an antioxidant enzyme that uses reduced glutathione (GSH) as a cofactor to detoxify lipid hydroperoxides. As a selenoprotein, the core function of GPX4 is the thiol-dependent redox reaction. In addition to GSH, other small molecules such as cysteine and homocysteine also contain thiols; yet, whether GPX4 can exploit cysteine and homocysteine to directly detoxify lipid hydroperoxides and inhibit ferroptosis has not been addressed. In this study, we found that cysteine and homocysteine inhibit ferroptosis in a GPX4-dependent manner. However, cysteine inhibits ferroptosis independent of GSH synthesis, and homocysteine inhibits ferroptosis through non-cysteine and non-GSH pathway. Furthermore, we used molecular docking and GPX4 activity analysis to study the binding patterns and affinity between GPX4 and GSH, cysteine, and homocysteine. We found that besides GSH, cysteine and homocysteine are also able to serve as substrates for GPX4 though the affinities of GPX4 with cysteine and homocysteine are lower than that with GSH. Importantly, GPX family and the GSH synthetase pathway might be asynchronously evolved. When GSH synthetase is absent, for example in Flexibacter, the fGPX exhibits higher affinity with cysteine and homocysteine than GSH. Taken together, the present study provided the understanding of the role of thiol-dependent redox systems in protecting cells from ferroptosis and propose that GSH might be a substitute for cysteine or homocysteine to be used as a cofactor for GPX4 during the evolution of aerobic metabolism.

Genotype-phenotype relationship and comparison between eastern and western patients with osteogenesis imperfecta

PURPOSE

To evaluate the genotypic and phenotypic relationship in a large cohort of OI patients and to compare the differences between eastern and western OI cohorts.

METHODS

A total of 671 OI patients were included. Pathogenic mutations were identified, phenotypic information was collected, and relationships between genotypes and phenotypes were analyzed. Literature about western OI cohorts was searched, and differences were compared between eastern and western OI cohorts.

RESULTS

A total of 560 OI patients were identified as carrying OI pathogenic mutations, and the positive detection rate of disease-causing gene mutations was 83.5%. Mutations in 15 OI candidate genes were identified, with COL1A1 (n = 308, 55%) and COL1A2 (n = 164, 29%) being the most common mutations, and SERPINF1 and WNT1 being the most common biallelic variants. Of the 414 probands, 48.8, 16.9, 29.2 and 5.1% had OI types I, III, IV and V, respectively. Peripheral fracture was the most common phenotype (96.6%), and femurs (34.7%) were most commonly affected. Vertebral compression fracture was observed in 43.5% of OI patients. Biallelic or COL1A2 mutation led to more bone deformities and poorer mobility than COL1A1 mutation (all P < 0.05). Glycine substitution of COL1A1 or COL1A2 or biallelic variants led to more severe phenotypes than haploinsufficiency of collagen type I α chains, which induced the mildest phenotypes. Although the gene mutation spectrum varied among countries, the fracture incidence was similar between eastern and western OI cohorts.

CONCLUSION

The findings are valuable for accurate diagnosis and treatment of OI, mechanism exploration and prognosis judgment. Genetic profiles of OI may vary among races, but the mechanism needs to be explored.

The global burden of lymphoma: estimates from the Global Burden of Disease 2019 study

OBJECTIVES

The aim of this study was to describe the global trends in the burden of lymphoma from 1990 to 2019.

STUDY DESIGN

The data used in this study were from the Global Burden of Disease 2019 study.

METHODS

This study described the age-standardised rates of incidence, prevalence, mortality, years of life lost (YLLs), years lived with disability (YLDs), and disability-adjusted life years (DALYs) of lymphoma (non-Hodgkin and Hodgkin's lymphoma, NHL and HL, respectively) annually from 1990 to 2019, stratified by sociodemographic index (SDI) and 21 world regions. The estimated annual percentage changes in these indexes were calculated.

RESULTS

In 2019, the age-standardised rates of HL per 100,000 population were lower than those of NHL in terms of incidence (1.1 vs 6.7 per 100,000 person-years, respectively) and prevalence (0.3 vs 5.7 per 100,000 person-years, respectively) but not mortality (21.6 vs 3.2 per 100,000 person-years, respectively). From 1999 to 2019, the global incidence of HL decreased and the incidence of NHL increased, and the prevalence of both HL and NHL increased, but the mortality rates decreased. When stratified by SDI, the incidence of HL decreased in all but middle-SDI regions, the mortality rate of HL decreased in all regions, and both the incidence and mortality rate of NHL increased in all but high-SDI regions. The prevalence of HL and NHL increased in all SDI regions, especially in middle-SDI regions. YLLs and DALYs of HL in all SDI regions and those of NHL in high-SDI regions decreased. YLDs slightly increased in middle- to high-SDI regions.

CONCLUSIONS

Lymphoma remains a major public health issue, and better prevention, precise identification, and promising treatments are vitally important.

PTH level might be associated with impaired quality of life in patients with nonsurgical hypoparathyroidism

OBJECTIVE

Nonsurgical hypoparathyroidism (ns-HP) is a rare disease. There are few studies on Quality of Life (QoL) among patients with ns-HP. This study aimed to investigate the QoL among ns-HP patients with regular conventional treatment, and explore the influence factors affecting QoL among these Chinese ns-HP patients.

METHODS

This is a cross-sectional study comparing 101 patients identified as ns-HP and 101 healthy controls. The questionnaires of Short Form 36 Health Survey questionnaire version 2(SF-36v2) were used to evaluate QoL.

RESULTS

Scores of all eight subdomains of SF-36v2 and physical component scores (PCS), mental component scores (MCS) were significantly lower in the ns-HP group compared with the healthy controls. The indices of all subdomains of SF-36v2 between Q1 (the lowest quartile) and Q4 (the highest quartile) groups were compared, suggesting higher percentages of detectable parathyroid hormone (PTH) before treatment in Q4 group among all QoL indices except two subdomains (physical function and body pain).

CONCLUSION

Both mental and physical QoL were impaired in the ns-HP patients even with regular conventional treatment for hypocalcemia, which were more severe in cases with lower baseline PTH levels.

High prevalence of vertebral deformity in tumor-induced osteomalacia associated with impaired bone microstructure

PURPOSE

Patients with tumor-induced osteomalacia (TIO) often suffer from irreversible height loss due to vertebral deformity. However, the prevalence of vertebral deformity in TIO patients varies among limited studies. In addition, the distribution and type of vertebral deformity, as well as its risk factors, remain unknown. This study aimed to identify the prevalence, distribution, type and risk factors for vertebral deformity in a large cohort of TIO patients.

METHODS

A total of 164 TIO patients were enrolled in this retrospective study. Deformity in vertebrae T4-L4 by lateral thoracolumbar spine radiographs was evaluated according to the semiquantitative method of Genant. Bone microstructure was evaluated by trabecular bone score (TBS) and high-resolution peripheral QCT (HR-pQCT).

RESULTS

Ninety-nine (99/164, 60.4%) patients had 517 deformed vertebrae with a bimodal pattern of distribution (T7-9 and T11-L1), and biconcave deformity was the most common type (267/517, 51.6%). Compared with patients without vertebral deformity, those with vertebral deformity had a higher male/female ratio, longer disease duration, more height loss, lower serum phosphate, higher bone turnover markers, lower TBS, lower areal bone mineral density (aBMD), lower peripheral volumetric BMD (vBMD) and worse microstructure. Lower trabecular vBMD and worse trabecular microstructure in the peripheral bone and lower spine TBS were associated with an increased risk of vertebral deformity independently of aBMD. After adjusting for the number of deformed vertebrae, we found little difference in clinical indexes among the patients with different types of vertebral deformity. However, we found significant correlations of clinical indexes with the number of deformed vertebrae and the spinal deformity index.

CONCLUSION

We reported a high prevalence of vertebral deformity in the largest cohort of TIO patients and described the vertebral deformity in detail for the first time. Risk factors for vertebral deformity included male sex, long disease duration, height loss, abnormal biochemical indexes and bone impairment. Clinical manifestation, biochemical indexes and bone impairment were correlated with the number of deformed vertebrae and degree of deformity, but not the type of deformity.

Scoping review on the role of social media in oral health promotion

OBJECTIVE

This review was conducted to assess the role of social media in oral health promotion by reviewing the perspectives and evaluation methods of previous related studies.

MATERIALS AND METHODS

The preferred reporting items PRISMA checklist was used to structure this review. Key search terms were identified to examine databases including PubMed, Web of Science and Embase. Manual searches in relevant journals and materials were also conducted in the meantime.

RESULTS

A total of 640 articles were identified after multi-source screening and duplicates removing, and finally 19 original studies published before April 2020 met the inclusion criteria. These studies mainly cover the fields of dentistry education and research, clinical treatment, and preventive dentistry. Both traditional and new-type social media have advantages and focuses, as well as biased information. Detailed assessment methods and indicators are classified into several groups, which could be selected to use in future research.

CONCLUSIONS

The application of social media in oral health promotion is becoming popular with the development of information technology. The broader use in the future, covering dentistry, mass health education, both long-term and short-term treatments of additional clinical content, requires further evaluation and supervision in online information sharing process. The reasonable selection of methods and indicators according to different topics and preference is of great importance.

[Chaihu Guizhi Decoction plus or minus formula combined with capecitabine inhibits IL-6/STAT3 signaling to suppress triple-negative breast cancer xenografts in nude mice]

OBJECTIVE

To investigate the effect of Chaihu Guizhi Decoction (CHGZD) combined with capecitabine on growth and apoptosis of subcutaneous triple-negative breast cancer xenografts in nude mice and explore the possible mechanism.

METHODS

Nude mouse models bearing subcutaneous triple-negative breast cancer xenografts were randomized into 6 groups (n=10) for treatment with distilled water (model group), low (10.62 g/kg), medium (21.23 g/kg) and high (42.46 g/kg) doses of CHGZD, capecitabine (0.2 mg/kg), or the combination of CHGZD (42.46 g/kg) and capecitabine (0.2 mg/k) once daily for 21 consecutive days. The general condition of mice was observed, and after 21-day treatments, the tumors were dissected for measurement of tumor volume and weight and histopathological examination with HE staining. Serum IL-6 levels of the mice were determined with enzyme-linked immunosorbent assay (ELISA), and the expression levels of IL-6, STAT3, p-STAT3, Bax, Bcl-2 and cyclin D1 in the tumor tissues were detected using real-time PCR and Western blotting.

RESULTS

Compared with those in the model group, the tumor-bearing mice receiving treatments with CHGZD showed significantly increased food intake with good general condition, sensitive responses, increased body weight, and lower tumor mass (P < 0.01). Compared with capecitabine treatment alone, treatment with CHGZD alone at the medium and high doses and the combined treatment all resulted in significantly higher tumor inhibition rates (P < 0.01), induced obvious tumor tissue degeneration and reduced the tumor cell density. Treatments with CHGZD, both alone and in combination with capecitabine, significantly decreased serum IL-6 level, lowered the mRNA expression levels of IL-6 and STAT3, the protein expressions of IL-6, STAT3 and P-STAT3 (P < 0.05), and the mRNA and protein expressions of Bcl-2 and cyclin D1 (P < 0.05), and increased the mRNA and protein expressions of Bax in the tumor tissues (P < 0.05).

CONCLUSION

CHGZD combined with capecitabine can significantly inhibit tumor growth in nude mice bearing triple-negative breast cancer xenografts, the mechanism of which may involve the inhibition of IL-6/STAT3 signaling pathway and regulation of Bax, Bcl-2 and cyclin D1 expressions to suppress tumor cell proliferation and differentiation and induce cell apoptosis.

The efficacy and safety of different doses of calcitriol combined with neutral phosphate in X-linked hypophosphatemia: a prospective study

The present study was the first prospective cohort evaluated the efficacy and safety of different doses of calcitriol in XLH children. The results suggested that a dose of 40 ng/kg/day calcitriol, compared with 20 ng/kg/day, was more effective in relieving the rickets, with similar safety outcomes. Further investigations were expected to set more dose groups.

INTRODUCTION

Dose recommended for calcitriol in X-linked hypophosphatemia (XLH) varies in different studies. Therefore, we aimed to compare the efficacy as well as the safety of 20 ng/kg/d and 40 ng/kg/d calcitriol in Chinese XLH pediatrics population.

METHODS

A 2-year, randomized, open-label, prospective study recruited 68 XLH children, which were randomized to receive either 40 ng/kg/day or 20 ng/kg/day calcitriol. Efficacy endpoints were the total Thacher ricket severity score (RSS) change from baseline to month 12 and 24, the difference in serum TALP level, fasting serum phosphate level, body height Z-score, and frequency of dental abscess. Safety assessments were done using renal ultrasound nephrocalcinosis grades (0-4), fasting serum and 24 h urine calcium level, and the occurrence of hyperparathyroidism.

RESULTS

The decrease in the total RSS from baseline was more significant in the high-dose group at 12 (difference 0.87, p = 0.049) and 24 month (difference 1.23, p = 0.011). The serum TALP level was significantly lower in the high-dose group at 6 months. Pi level, height Z-score change, frequency of dental abscess and ratio of de novo nephrocalcinosis were comparable. A lower incidence of secondary hyperparathyroidism was seen in the high-dose group (p < 0.0001).

CONCLUSION

For the first time in this prospective cohort, 40 ng/kg/d calcitriol was shown to be the more effective therapy in XLH children than the 20 ng/kg/d. Moreover, 40 ng/kg/d calcitriol was not associated with increasing adverse events.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT 03,820,518.

BMSC-Derived ApoEVs Promote Craniofacial Bone Repair via ROS/JNK Signaling

Bone defect caused by trauma, neoplasia, congenital defects, or periodontal disease is a major cause of disability and physical limitation. The transplantation of bone marrow mesenchymal stem cells (BMSCs) promotes bone repair and regeneration. However, it has been shown that most BMSCs die within a short period after transplantation. During apoptosis, BMSCs generate a large number of apoptotic cell-derived extracellular vesicles (ApoEVs). This study aims to understand the potential role of ApoEVs in craniofacial bone defect repair and regeneration. First, we confirmed that BMSCs undergo apoptosis within 2 d after transplantation into the defect of the cranium. Abundant ApoEVs were generated from apoptotic BMSCs. Uptake of ApoEVs efficiently promoted the proliferation, migration, and osteogenic differentiation of recipient BMSCs in vitro. ApoEVs from cells in the middle stage of apoptosis were the most efficient to enhance the regenerative capacity of BMSCs. Moreover, a critical size bone defect model in rats was used to evaluate the osteogenic property of ApoEVs in vivo. Local transplantation of ApoEVs promoted bone regeneration in the calvarial defect. Mechanistically, ApoEVs promoted new bone formation by increasing intracellular reactive oxygen species to activate JNK signaling. This study reveals a previously unknown role of the dying transplanted BMSCs in promoting the viability of endogenous BMSCs and repairing the calvarial defects. Since it could avoid several adverse effects and limits of BMSC cytotherapy, treatment of ApoEVs might be a promising strategy in craniofacial bone repair and regeneration.

Safety and efficacy of common vitamin D supplementation in primary hyperparathyroidism and coexistent vitamin D deficiency and insufficiency: a systematic review and meta-analysis

PURPOSE

Primary hyperparathyroidism (PHPT) is characterized by excessive secretion of parathyroid hormone (PTH). Vitamin D deficiency can stimulate parathyroid secretion. However, whether to correct vitamin D deficiency in patients with PHPT is controversial. We aimed to evaluate the safety and efficacy of vitamin D replacement in patients with PHPT.

METHODS

We searched PubMed, Cochrane Library, and Embase. The relevant data were extracted from the included documents. The methodological items for non-randomized studies score entries were used for evaluation of quality. Review Manager 5.3 and Stata 12.0 were used for statistical analysis.

RESULTS

A total of 11 articles were included with a total of 388 patients. The serum calcium mean difference (MD) was - 0.06 mg/dL [95% confidence interval (95% CI) - 0.16, 0.04]. Subgroup analysis showed that serum calcium levels did not change if the intervention time exceeded 1 month. The 24-h urinary calcium MD was 36.78 mg/day (95% CI - 37.15, 110.71), which indicated that there was no significant effect of vitamin D supplementation on 24-h urinary calcium levels. The MD of PTH was - 16.01 pg/mL (95% CI - 28.79, - 3.24). Subgroup analysis according to the intervention time showed that vitamin D intervention for more than 1 month significantly reduced PTH levels. The ALP MD was - 10.81 U/L (95% CI - 13.98, - 7.63), which indicated Vitamin D supplementation reduced its level. The MD of 25-hydroxyvitamin D was 22.09 μg/L (95% CI 15.01, 29.17), and no source of heterogeneity was found.

CONCLUSION

Vitamin D supplementation in patients with PHPT and vitamin D deficiency significantly reduces PTH and ALP levels without causing hypercalcemia and hypercalciuria.

MiR-22-3p regulates the proliferation and invasion of Wilms' tumor cells by targeting AKT3

OBJECTIVE

In this study, the regulatory mechanism of miR-22-3p/AKT3 in the development of Wilms' tumor (WT) was investigated.

PATIENTS AND METHODS

Twenty-seven pairs of surgical tumor specimens and adjacent normal tissues were obtained from Jining No. 1 People's Hospital. The expression level of miR-22-3p in WT tissues and cell lines was measured by quantitative RT-PCR. MTT and transwell assays were performed to analyze cell proliferation and invasion in WT. The relationship between miR-22-3p and AKT3 was verified by a Dual-Luciferase assay. The protein expression of AKT3 was evaluated by Western blotting analysis.

RESULTS

MiR-22-3p was downregulated and AKT3 was upregulated in WT. Functionally, overexpression of miR-22-3p inhibited cell proliferation and invasion in WT. Moreover, miR-22-3p directly targets AKT3. The knockdown of AKT3 suppressed cell proliferation and invasion in WT. In addition, upregulation of AKT3 restored the tumor suppressive effect of miR-22-3p in WT.

CONCLUSIONS

MiR-22-3p inhibits the proliferation and invasion of WT cells by downregulating AKT3, indicating that miR-22-3p may be developed as a new biomarker for the diagnosis of WT.

Iron deficiency plays essential roles in the trigger, treatment, and prognosis of autosomal dominant hypophosphatemic rickets

By analyzing iron status of 14 ADHR patients, we found that iron deficiency was an important trigger of ADHR. Correcting iron deficiency significantly improved patients' symptoms. Meanwhile, patients' serum phosphate showed positive correlations with iron metabolism parameters and hemoglobin-related parameters, suggesting the necessity of monitoring and correcting the iron status in ADHR.

INTRODUCTION

Autosomal dominant hypophosphatemic rickets (ADHR) is unique for its incomplete penetrance, variety of disease onsets, and waxing and waning phenotypes. Iron deficiency is a trigger of ADHR. This study aimed to clarify the role of iron deficiency in ADHR.

METHODS

Data of clinical manifestations and laboratory examinations were collected from patients among eight kindreds with ADHR. Multiple regression and Pearson's correlation tests were performed to test the relationships of serum phosphate levels and other laboratory variables during the patients' follow-ups.

RESULTS

Among 23 ADHR patients with fibroblast growth factor 23 (FGF23) mutations, 14 patients presented with obvious symptoms. Ten patients had iron deficiency at the onset of ADHR, coinciding with menarche, menorrhagia, pregnancy, and chronic gastrointestinal bleeding. Two patients who did not have their iron status tested presented with symptoms after abortion and pregnancy in one patient each, which suggested that they also had iron deficiency at onset. Patients were treated with ferrous succinate tablets, vitamin C, and neutral phosphate and calcitriol. With correction of the iron status, the patients' symptoms showed notable improvement, with increased serum phosphate levels. Two patients' FGF23 levels also declined to the normal range. There were strong correlations between serum phosphate and serum iron levels (r = 0.7689, p < 0.0001), serum ferritin levels (r = 0.5312, p = 0.002), iron saturation (r = 0.7907, p < 0.0001), and transferrin saturation (r = 0.7875, p < 0.001). We also examined the relationships between serum phosphate levels and hemoglobin-related indices, which were significant (hemoglobin: r = 0.71, p < 0.0001; MCV: r = 0.7589, p < 0.0001; MCH: r = 0.8218, p < 0.0001; and MCHC: r = 0.7751, p < 0.0001). Longitudinal data of six patients' follow-up also showed synchronous changes in serum phosphate with serum iron levels.

CONCLUSIONS

Iron deficiency plays an important role in triggering ADHR. Monitoring and correcting the iron status are helpful for diagnosing and treating ADHR. Iron metabolism parameters and hemoglobin-related parameters are positively correlated with serum phosphate levels in patients with ADHR and iron deficiency, and these might serve as good indicators of prognosis of ADHR.

[Effects of neuromuscular exercise therapy on the joint stability of patients with knee osteoarthritis]

Objective: To evaluate the effects of neuromuscular exercise therapy on joint stability of knee osteoarthritis (OA) patients. Methods: One hundred and ten patients with knee OA were enrolled in this ongoing prospective cohort study at Arthritis Clinic and Research Center, Peking University People's Hospital from September 2017 to October 2018. The treatment consisted of six-week neuromuscular exercise therapy. The participants were followed up at 6 weeks and 3 months after the therapy. The stability of the joint was evaluated by the index of knee joint stability (IKJS), which was extracted by a novel knee-aiming task combined with the multiscale entropy (MSE) analysis of the complexity of the light spot trajectories. The secondary outcomes were pain on the visual analogue scale (VAS, 0-100), the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), quality of life on the Euro-quality of life-5 Dimensional (EQ-5D) VAS form, 30-second chair stand test and 40-meter walk test. One-way repeated measures ANOVA analysis was applied to compare the outcomes at baseline and 6 weeks and 3 months. Pearson partial analysis was used to investigate the correlation between the IKJS and the Kellgren-Lawrence (K/L) rate, pain and knee function. Results: Ninety-six participants ((65±8) years, 21 males, 75 females) completed 3-month follow-up. There was a significant improvement in IKJS at the 6-week visit compared with that at baseline (0.369, 95% confidence interval (CI) 0.241-0.496, P<0.001). The IKJS dropped at 3-month visit compared with 6-week visit, but was still better than that at baseline (0.178, 95%CI: 0.042-0.314, P=0.008). The correlation between IKJS and K/L rate, severity of pain, WOMAC or knee function was not significant (r=-0.131, -0.059, -0.231, 0.124, all P>0.05). There was improvement in pain VAS, WOMAC, EQ-5D-VAS, 30-second chair stand test and 40-meter walk test at 6 weeks and 3 months (all P<0.05). Conclusion: The neuromuscular exercise therapy is effective in improving the joint stability of the knee OA patients. However, the effect gradually diminished over time. In addition, neuromuscular exercise can help relieve pain, improve the function and quality of life in patients with knee OA.

Bone microstructure of adult patients with non-surgical hypoparathyroidism assessed by high-resolution peripheral quantitative computed tomography

There is limited evidence regarding changes in bone microstructure in patients with hypoparathyroidism. In the current study, we used a non-invasive technique to assess bone structure in hypoparathyroidism patients and discovered site-specific changes which were mainly influenced by age and menstrual status. Such changes were more prominent in the trabeculae as well as in non-surgical as opposed to post-surgical patients.

INTRODUCTION

Hypoparathyroidism (hypoPT) is a rare disease characterized by the lack of parathyroid hormone. There is limited evidence regarding changes in bone microstructure in patients with non-surgical hypoPT. We investigated bone microstructure of patients with non-surgical hypoPT using a non-invasive technique.

METHODS

Patients with hypoPT were assessed using high-resolution peripheral quantitative computed tomography (HR-pQCT) and compared to age- and sex-matched healthy controls randomly selected from a pre-existing HR-pQCT database in a cross-sectional study. Preliminary comparison between patients with different etiologies of hypoPT was performed. Associations between bone microstructure and clinical parameters were investigated using correlation and regression analyses.

RESULTS

A total of 94 patients with non-surgical hypoPT were recruited. Patients displayed an increase in trabecular volumetric BMD of the tibia (170.57 ± 34.32 vs. 156.48 ± 40.55 mg HA/cm³, p = 0.011) and increase in trabecular number of both the radius (1.48 ± 0.29 vs. 1.36 ± 0.22 mm^-1, p = 0.003) and tibia (1.42 ± 0.23 vs. 1.24 ± 0.22 mm^-1, p < 0.001) compared to healthy controls. Trabecular number was higher for non-surgical hypoPT compared to post-surgical hypoPT (1.37 ± 0.25 and 1.17 ± 0.13 mm^-1, p = 0.022). Trends towards increase in cortical volumetric BMD were only present for post-menopausal female and male patients above the age of 50. For female patients, cortical volumetric BMD and area increased with age and decreased after menopause. For males, age had little influence on bone microstructure, but cortical porosity increased with longer treatment durations.

CONCLUSIONS

Results from this pilot study suggested that both cortical and trabecular bone were altered in this group of patients with hypoPT. Etiology for hypoPT might influence bone microstructure, mainly on trabeculae. Age, menstrual status, and treatment duration were likely to influence bone microstructure in hypoPT.

Classification and treatment strategies for condylar fractures in children

In this study, we aimed to describe a classification method (position and displacement (PD) classification) and the corresponding treatment strategies for condylar fractures in children, based on the anatomical position and displacement of the fractures. Moreover, we aimed to explore the effect of the treatment strategies for condylar fractures in children. Such fractures were classified into the following three types by PD classification: condylar head fracture (type A), mildly displaced condylar neck and base fracture (type B), and severely displaced condylar neck and base fracture (type C). According to this classification, we proposed the corresponding treatment strategy of closed treatment for types A and B fractures and open treatment for type C fractures. Eighty-four patients who had 123 condylar fractures (type A = 97, type B = 16, type C = 10) were included in this study. Type A fractures showed the restoration of normal function with favourable remodelling in the condyles. Types B and C fractures had good function and symmetry in the condylar angle and height of the condylar neck. The PD classification and corresponding treatment strategies may serve as a better option for the clinical treatment of condylar fractures in children.

Predicting the intervention threshold for initiating osteoporosis treatment among postmenopausal women in China: a cost-effectiveness analysis based on real-world data

This study built a micro-simulation Markov model to determine the treatment threshold of osteoporosis in postmenopausal women in Mainland China. Treatment with zoledronate is cost-effective when FRAX-based (Fracture risk assessment tool) fracture probability is over 7%.

INTRODUCTION

The purpose of this study is to estimate FRAX-based fracture probabilities in Mainland China using real-world data, at which intervention could be cost-effective.

METHODS

We developed a micro-simulation Markov model to capture osteoporosis states and relevant morbidities including hip fracture, vertebral fracture, and wrist fracture. Baseline characteristics including incidences of osteoporosis and distribution of risk factors were derived from the Peking Vertebral Fracture study, the largest prospective cohort study of postmenopausal women in Mainland China. We projected incidences of fractures and deaths by age groups under two treatment scenarios: 1) no treatment, and 2) zoledronate. We also projected total quality-adjusted life-years (QALY) and total costs including fracture management and osteoporosis drugs for cost-effectiveness analysis. Cost-effective intervention thresholds were calculated based on the Chinese FRAX model.

RESULTS

Treatment with zoledronate was cost-effective when the 10-year probability of major osteoporotic fracture based on FRAX was above 7%. The FRAX threshold increased by age from 51 to 65 years old, and decreased in elder age groups, ranging from 4% to 9%.

CONCLUSIONS

Using real-world data, our model indicated that widespread use of zoledronate was of both clinical and economic benefit among Chinese postmenopausal women. Using a FRAX-based intervention threshold of 7% with zoledronate should permit cost-effective access to therapy to patients and contribute to reducing the disease burden of osteoporosis in Mainland China.

Impaired geometry, volumetric density, and microstructure of cortical and trabecular bone assessed by HR-pQCT in both sporadic and MEN1-related primary hyperparathyroidism

This study evaluated bone features of PHPT using HR-pQCT. The results showed both cortical and trabecular bones were significantly impaired in PHPT patients. Male and female PHPT patients suffered similar damages in bone. HR-pQCT indices were not observed to differ in MEN1 and sporadic PHPT patients.

INTRODUCTION

High-resolution peripheral quantitative CT is a novel imaging technique used to separately assess trabecular and cortical bone status of the radius and tibia in vivo. Using HR-pQCT, we aimed to evaluate bone features of primary hyperparathyroidism patients in a Chinese population and reveal similarities and differences in bone features in multiple endocrine neoplasia type 1-related PHPT and sporadic PHPT patients in the Chinese population.

METHODS

A case-control study was designed. In 58 PHPT patients and 58 sex- and age-matched healthy controls, the distal radius and tibia were scanned using HR-pQCT. Areal bone mineral density (aBMD) was also determined in PHPT patients using dual-energy X-ray absorptiometry (DXA).

RESULTS

In comparison with controls, PHPT patients were observed to exhibit reduced volumetric BMD at the cortical and trabecular compartments, thinner cortices, and more widely spaced trabeculae. Significant differences were still observed when comparing data of female and male patients with age-matched controls separately. MHPT patients (n = 11) were found to have lower aBMD Z-scores in the lumbar spine, trochanteric region, and total hip compared with sporadic PHPT patients (n = 47), while no differences were observed in HR-pQCT indices between the two groups. In multiple linear regression models, no significant correlations were identified between PTH and HR-pQCT indices. However, height was found to positively correlate with HR-pQCT-derived trabecular indices at both the radius and tibia.

CONCLUSIONS

PHPT affects geometry, volumetric density, and microstructure in both the cortical and trabecular bones in both male and female Chinese patients. MHPT patients were observed to have reduced aBMD as determined by DXA in the lumbar spine and hip in comparison with sporadic PHPT patients. However, HR-pQCT indices were not observed to differ.

Impaired bone microarchitecture in distal interphalangeal joints in patients with primary hypertrophic osteoarthropathy assessed by high-resolution peripheral quantitative computed tomography

This study aimed to investigate the bone impairment in finger joints in PHO patients by HR-pQCT. Results showed distinguished differences in bone architecture and biomechanics parameters at DIPs between PHO patients and healthy controls using HR-pQCT assessment. Besides, serum PGE2, hsCRP and ESR levels were found negatively correlated with total vBMD.

INTRODUCTION

This study aimed to investigate the bone impairment in finger joints in primary hypertrophic osteoarthropathy (PHO) patients firstly by high-resolution peripheral quantitative computed tomography (HR-pQCT).

METHODS

Fifteen PHO patients and 15 healthy controls were enrolled in this study. Bone erosions in hands at distal interphalangeal joints (DIPs) in both PHO patients and controls were evaluated by X-ray. Bone geometry, vBMD, microstructure parameters, and size of individual bone erosion were also measured at the 3rd DIP by HR-pQCT as well. Blood biochemistry levels between the two groups were also compared.

RESULTS

Compared to X-ray, HR-pQCT assessment were more sensitive for detection of bone erosions, with 14 PHO patients by HR-pQCT versus ten PHO patients by X-ray judged at the 3rd DIP. The average depth, width, and volume of erosions size in PHO patients were 1.38 ± 0.80 mm, 0.79 ± 0.27 mm, and 1.71 ± 0.52 mm³, respectively. The bone cross-areas including total area (+ 25.3%, p ≤ 0.05), trabecular area (+ 56.2%, p ≤ 0.05), and cortical perimeter (+ 10.7%, p ≤ 0.05) at the defined region of interest of 3rd DIP was significantly larger than controls. Total vBMD was 11.9% lower in PHO patients compared with the controls (p ≤ 0.05). Biochemical test results showed the increased levels of inflammatory cytokines, bone resorption markers, and joint degeneration markers in PHO patients. Serum prostaglandin PGE2, high-sensitive C-reactive protein (hsCRP) and erythrocyte sedimentation rate (ESR) levels were found negatively correlated with total vBMD.

CONCLUSIONS

This study demonstrated higher sensitivity of the HR-pQCT measurement at DIPs by showing the differences in architecture and biomechanics parameters at DIPs between the PHO patients and healthy controls, which would be of interest clinically to investigate bone deterioration in PHO patients.

P1689Nighttime blood pressure and dipping patterns relate to sodium sensitivity of blood pressure

Background

Attenuated nighttime blood pressure (BP) fall during a high-sodium diet is associated with higher sodium sensitivity of BP. However, the prognostic value for sodium sensitivity of nighttime BP profile during a habitual diet is not fully understood.

Purpose

To elucidate the usefulness of nighttime BP and dipping patterns under a habitual diet in assessing sodium sensitivity.

Methods

We conducted a dietary intervention study among 250 resident aged 18–60 years with high-normal or stage I hypertension in rural areas of northern China. The 24-hour ambulatory BP monitoring and baseline survey were performed for each participant under a habitual diet during the first 3 days. Then participants underwent a 7-day low-sodium intervention (51.3mmol sodium per day), followed by a 7-day high-sodium intervention (307.8mmol sodium per day). Three clinic BP measurements were obtained in every morning of the 3-day baseline observation and days 5, 6, and 7 of each intervention period.

Results

Among 250 participants, 86 (34.4%) had daytime hypertension (DH) and 149 (59.6%) had nighttime hypertension (NH). The systolic BP (SBP) responses to low-sodium and high-sodium intervention were significantly higher in those with NH than those without irrespective of DH status [−8.1 (−9.3, −7.0) vs. −5.5 (−7.0, −4.1) mmHg, P=0.001; and 13.0 (11.6, 14.3) vs. 11.0 (9.3, 12.7) mmHg, P=0.038, respectively]. Compared with dippers, extreme dippers had significantly higher SBP responses to low-sodium and high sodium intervention independently of 24-hour SBP. Moreover, the quadratic curve between nighttime SBP fall and SBP responses to low-sodium (β=−105.5 for quadratic term, P=0.015) and high-sodium (β=108.9 for quadratic term, P=0.035) intervention suggested both non-dipping and extreme dipping might indicate higher sodium sensitivity.

Conclusions

NH as well as non-dipping and extreme dipping determined during a habitual diet might indicate higher sodium sensitivity, which highlights the potential usefulness of nighttime BP profile in assessing sodium sensitivity.

Acknowledgement/Funding

This study is supported by the National Natural Science Foundation of China (grant no. 81570386)

[Mechanism of angiotensin II (Ang II) on the proliferation of human hepatoma cell line HepG2 cells]

Objective: To study the effect and mechanism of angiotensin (Ang II) on the proliferation of human hepatocellular carcinoma HepG2 cells. Methods: The effects of different concentrations of Ang II's (10(-8)-10(-4) mol/L) on proliferated hepatocellular carcinoma HepG2 cells were detected by CCK-8 assay. The expression of angiotensin II type 1 receptor (AT1) protein and activation of ERK1/2 protein in hepatocellular carcinoma HepG2 cells after processing with Ang II were assayed by Western blot. The cells were pretreated with candesartan (AT1 receptor antagonist), sorafenib (Raf kinase inhibitor) and PD98059 (ERK1/2 inhibitor) for 1.5 h and then Ang II (10(-6) mol/L) was added. CCK-8 assay was used to determine whether it could reverse the proliferation of Ang II, and ERK phosphorylation levels were detected by Western blot. The changes in Bcl-2 and c-myc gene expression before and after Ang II processing were detected by Rt-PCR. According to different data, t-test, one-way analysis of variance or SNK method were used for statistical analysis. Results: HepG2 cells treated with different concentrations of Ang II promoted cell proliferation after 24h and 48h. After 24 h, cell vitality was strongest with Ang II concentration 10(-5) mol/L and the absorbance value was 0.990 8±0.097 8; and again after 48 h, the cell viability was strongest with Ang II concentration 10(-6) mol/L and the absorbance value was 1.302 7 ± 0.030 9. Moreover, the pro-proliferation effect of Ang II on HepG2 cells blocked candesartan, sorafenib and ERK1/2 isolated inhibitors. After treatment with 10(-6) mol/L Ang II, Western blot showed that Ang II significantly promoted AT1 receptor expression and phosphorylation of ERK1/2 protein confirmed that Ang II activated the AT1/RAF/ERK1/2 signaling pathway. In addition, Rt-PCR detection showed that the downstream of Bcl-2 and c-myc genes expressions rose significantly when the concentration of Ang II ranged from 10(-8) to 10(-6) mol/L. Conclusion: Ang II can promote the proliferation of HepG2 cells by activating AT1/Raf /ERK1/2 signaling pathway and enhance the downstream of Bcl-2 and c-myc gene expression.

Health-related quality of life in children with osteogenesis imperfecta: a large-sample study

In this large-sample study, we demonstrated that osteogenesis imperfecta (OI) significantly impaired the quality of life (QoL) in children. Moderate/severe OI patients had worse QoL scores than patients with mild OI. Furthermore, the QoL for OI patients was correlated with the presence of pathogenic gene mutations.

INTRODUCTION

Osteogenesis imperfecta (OI) is a hereditary disease characterized by multiple fragility fractures and progressive skeletal deformities. No detailed investigations about the quality of life (QoL) have been carried out in a large sample of patients with OI. We evaluated the QoL and its influencing factors in a large and well-characterized OI cohort.

METHODS

We used a validated questionnaire of PedsQL 4.0 to evaluate the health-related quality of life (HRQoL) of children and adolescents with OI. We compared HRQoL among patients with OI types I, III, and IV. The relationship between HRQoL and pathogenic mutations in candidate OI genes was investigated. We also evaluated the influencing factors of HRQoL in OI patients.

RESULTS

A total of 138 children with OI and 138 healthy controls were enrolled in this study. The HRQoL scores of OI patients were 64.4 ± 30.0, 71.9 ± 22.2, 75.7 ± 24.8, 63.7 ± 24.5, and 68.9 ± 22.0 in physical, emotional, social, school functioning, and total score, respectively, which were significantly lower than those of healthy children (86.5 ± 12.7, 83.3 ± 16.0, 92.1 ± 11.8, 87.5 ± 11.8, and 87.3 ± 10.7, all p < 0.01). Moderate and severe OI (type III/IV) patients had poorer HRQoL scores than patients with mild OI (type I). Gene mutations inducing qualitative defects in type I collagen led to worse HRQoL scores than those with quantitative defects in type I collagen, except in emotional functioning. The total HRQoL score was positively correlated with family income, lumbar, and femoral bone mineral density (BMD) Z-scores and negatively correlated with disease severity and fracture frequency.

CONCLUSION

HRQoL was significantly impaired in OI patients, and patients with more severe OI had poorer HRQoL scores. For the first time, we found that children with qualitative defects in type I collagen had poorer HRQoL scores than those with quantitative defects in type I collagen.

Mutation update and long-term outcome after treatment with active vitamin D3 in Chinese patients with pseudovitamin D-deficiency rickets (PDDR)

Pseudovitamin D-deficiency rickets is a rare disease which is caused by CYP27B1. In this study, we identified 9 mutations in 7 PDDR patients. In addition, we observed the response to long-term treatment of calcitriol in 15 Chinese patients with PDDR, which showed that the biochemical abnormalities had been corrected satisfactorily after 1-year treatment.

INTRODUCTION

Pseudovitamin D-deficiency rickets is a rare autosomal recessive disorder resulting from a defect in 25-hydroxyvitamin D 1α-hydroxylase, which is encoded by CYP27B1. The purpose of this study was to identify the CYP27B1 mutations and investigate the response to long-term treatment of calcitriol in Chinese patients with PDDR.

METHODS

We investigated CYP27B1 mutations in seven individuals from six separate families. To investigate the response to long-term (13 years) treatment with calcitriol in PDDR patients, we additionally collected clinical data of eight families from our previous report and analyzed their biochemical parameter and radiographic changes during the treatment.

RESULTS

Nine different mutations were identified: two novel missense mutations (G194R, R259L), three novel and one reported deletion mutations (c1442delA, c1504delA, c311-321del, and c. 48-60del), two novel nonsense mutations (c.85G>T, c.580G>T), and a reported insertion mutation (c1325-1332insCCCACCC). The statistical analysis revealed that parathyroid hormone (PTH) and ALP significantly decreased after 6-month and 1-year treatment with calcitriol respectively. Urine calcium was measured in all the patients without kidney stones being documented. After 6-year treatment, the radiographic abnormalities had also been improved. Two patients who had reached their final height are both with short stature (height Z-score below - 2.0).

CONCLUSIONS

We identified seven novel mutations of CYP27B1 gene in seven Chinese PDDR families. Our findings revealed after 1-year treatment of active vitamin D₃, PTH and ALP significantly decreased. The correction of the biochemical abnormalities had not improved the final height satisfactorily.

Novel compound heterozygous mutations in SERPINH1 cause rare autosomal recessive osteogenesis imperfecta type X

We identified novel compound heterozygous mutations in SERPINH1 in a Chinese boy suffering from recurrent fractures, femoral deformities, and growth retardation, which resulted in extremely rare autosomal recessive OI type X. Long-term treatment of BPs was effective in increasing BMD Z-score, reducing fracture incidence and reshaping vertebrae compression.

INTRODUCTION

Osteogenesis imperfecta (OI) is a heritable bone disorder characterized by low bone mineral density, recurrent fractures, and progressive bone deformities. Mutation in serpin peptidase inhibitor clade H, member 1 (SERPINH1), which encodes heat shock protein 47 (HSP47), leads to rare autosomal recessive OI type X. We aimed to detect the phenotype and the pathogenic mutation of OI type X in a boy from a non-consanguineous Chinese family.

METHODS

We investigated the pathogenic mutations and analyzed their relationship with the phenotype in the patient using next-generation sequencing (NGS) and Sanger sequencing. Moreover, the efficacy of long-term bisphosphonate treatment in this patient was evaluated.

RESULTS

The patient suffered from multiple fractures, low bone mass, and bone deformities in the femur, without dentinogenesis imperfecta or hearing loss. Compound heterozygous variants were found in SERPINH1 as follows: c.149 T>G in exon 2 and c.1214G>A in exon 5. His parents were heterozygous carriers of each of these mutations, respectively. Bisphosphonates could be helpful in increasing BMD Z-score, reducing bone fracture risk and reshaping the compressed vertebral bodies of this patient.

CONCLUSION

We reported novel compound heterozygous mutations in SERPINH1 in a Chinese OI patient for the first time, which expanded the spectrum of phenotype and genotype of extremely rare OI type X.

Correction to: Gene mutation spectrum and genotype-phenotype correlation in a cohort of Chinese osteogenesis imperfecta patients revealed by targeted next generation sequencing

In Table 2:Family 6 should be c.643-13_662delCTATCTTTTCTAGGGTCCCATGGGTCCCCGAGG instead of c.643-13_662delCTATCTTTTCTAGGGTCCCATGGGTCCCC.Family 33 should be c.271_279dupGCCCTCTCG instead of c.271_279dupGCCCTCT.In the 2nd para. of the Molecular diagnosis, section t(5;8)(q32;q21) should be t(5;7)(q32;q21).

Gene mutation spectrum and genotype-phenotype correlation in a cohort of Chinese osteogenesis imperfecta patients revealed by targeted next generation sequencing

The achievement of more accurate diagnosis would greatly benefit the management of patients with osteogenesis imperfecta (OI). In this study, we present the largest OI sample in China as screened by next generation sequencing. In particular, we successfully identified 81 variants, which included 45 novel variants. We further did a genotype-phenotype analysis, which helps make a better understanding of OI.

INTRODUCTION

This study aims to reveal the gene mutation spectrum and the genotype-phenotype relationship among Chinese OI patients by next generation sequencing (NGS).

METHODS

We developed a NGS-based panel for targeted sequencing of all exons of 14 genes related to OI, and performed diagnostic gene sequencing for a cohort of 103 Chinese OI patients from 101 unrelated families. Mutations identified by NGS were further confirmed by Sanger sequencing and co-segregation analysis.

RESULTS

Of the 103 patients from 101 unrelated OI families, we identified 79 mutations, including 43 novel mutations (11 frameshift, 17 missense, 5 nonsense, 9 splice site, and 1 chromosome translocation) in 90 patients (87.4%). Mutations in genes encoding type I collagen, COL1A1 (n = 37), and COL1A2 (n = 29) accounts for 73.3% of all molecularly diagnosed patients, followed by IFITM5 (n = 9, 10%), SERPINF1 (n = 4, 4.4%), WNT1 (n = 4, 4.4%), FKBP10 (n = 3, 3.3%), TMEM38B (n = 3, 3.3%), and PLOD2 (n = 1, 1.1%). This corresponds to 75 autosomal dominant inherited (AD) OI patients and 15 autosomal recessive (AR) inherited patients. Compared with AD inherited OI patients, AR inherited patients had lower bone mineral density (BMD) at spine (P = 0.05) and less frequent blue sclera (P = 0.001). Patients with type I collagen qualitative defects had lower femoral neck BMD Z-score (P = 0.034) and were shorter compared with patients with type I collagen quantitative defects (P = 0.022).

CONCLUSION

We revealed the gene mutation spectrum in Chinese OI patients, and novel mutations identified here expanded the mutation catalog and genotype and phenotype relationships among OI patients.

A novel large fragment deletion in PLS3 causes rare X-linked early-onset osteoporosis and response to zoledronic acid

We identified a novel large fragment deletion from intron 9 to 3'UTR in PLS3 (E10-E16del) in one Chinese boy with X-linked early-onset osteoporosis and vertebral fractures, which expanded the pathogenic spectrum of X-linked early-onset osteoporosis. Treatment with zoledronic acid was beneficial for increasing BMD and reshaping the vertebral bodies of this patient.

INTRODUCTION

X-linked early-onset osteoporosis is a rare disease, which is characterized by low bone mineral density (BMD), vertebral compression fractures (VCFs), and/or long bone fractures. We aimed to detect the phenotype and the underlying pathogenic mutation of X-linked early-onset osteoporosis in a boy from a nonconsanguineous Chinese family.

METHODS

We investigated the pathogenic mutation of the patient with X-linked early-onset osteoporosis by targeted next-generation sequencing and confirmed it by Sanger sequencing. We also observed the effects of zoledronic acid on fracture frequency and BMD of the patient.

RESULTS

Low BMD and multiple VCFs were the main phenotypes of X-linked early-onset osteoporosis. We identified a total of 12,229 bp deletion in PLS3, involving intron 9 to the 3'UTR (E10-E16 del). This large fragment deletion might be mediated by Alu repeats and microhomology of 26 bp at each breakpoint junction. Zoledronic acid treatment could significantly increase the Z-score of BMD and reshape the compressed vertebral bodies.

CONCLUSION

We identified a large fragment deletion mutation in PLS3 for the first time and elucidated the possible mechanism of the deletion, which led to X-linked early-onset osteoporosis and multiple vertebral fractures. Our findings would enrich the etiology spectrum of this rare disease.

Vertebral fracture in postmenopausal Chinese women: a population-based study

In a random sample of postmenopausal Chinese women, the prevalence of radiographic vertebral fractures increased from 13% between ages 50 and 59 to over 50% after age 80 years. A model with seven clinical risk factors predicted the probability of vertebral fractures as well with as without BMD and better than a model with only three risk factors. More than half an hour of outdoor activity per day might correlate with lower risk of vertebral fracture in this population.

INTRODUCTION

We aimed to describe the prevalence and develop a model for prediction of radiographic vertebral fractures in a large random sample of postmenopausal Chinese women.

METHODS

We enrolled 1760 women from an age-stratified random sample of postmenopausal women in Beijing, China. The presence of vertebral fracture was assessed by semi-quantitative grading of lateral thoracolumbar radiographs, risk factors by interview, bone mineral density (BMD) of the proximal femur and lumbar spine by dual x-ray absorptiometry (DXA), and markers of bone turnover from a fasting blood sample. Associations of these factors were analyzed in logistic models and discrimination by areas of receiver operating characteristics curves (AUC).

RESULTS

The prevalence of vertebral fracture, ranged from 13.4% ages 50 to 59 years old to 58.1% at age 80 years or older. Older age, a history of non-vertebral fracture, lower femoral neck BMD T-score, body mass index (BMI), height loss, housework, and less than half an hour of outdoor activity were significantly associated with increased probability of having a vertebral fracture. A model with those seven factors had a similar AUC with or without BMD and performed better than a simple model with three factors.

CONCLUSION

This study is from a true random sample of postmenopausal women in urban China with high response rate. The prevalence of vertebral fractures in postmenopausal women in Beijing increases from 13% under age 60 to over 50% by age 80 years. A model with seven clinical risk factors with or without BMD is better than simple models and may guide the use of spine x-rays to identify women with vertebral fractures. More than half an hour of outdoor activity might correlate with lower risk of vertebral fracture in this population.

Association between bone mineral density, muscle strength, and vitamin D status in patients with myasthenia gravis: a cross-sectional study

Myasthenia gravis (MG) patients had low proximal hip BMD, which could be explained by reduced muscle strength, elevated bone resorption markers, vitamin D deficiency, and increased PTH levels in those with MG compared to controls.

INTRODUCTION

Muscle strength is closely correlated with bone mineral density (BMD) and vitamin D status. Here, we evaluated muscle strength, BMD, and vitamin D status in a large sample of Chinese patients with MG.

METHODS

In this cross-sectional survey, 86 patients with MG without glucocorticoid treatment and 86 healthy controls were included. Serum levels of 25-hydroxyvitamin D [25OHD], parathyroid hormone (PTH), bone turnover markers (BTMs), and BMD were measured and compared between the two groups. Grip strength and one-leg standing time (OLST) were also assessed in MG patients.

RESULTS

Low grip strength and short OLST were found in 11 (12.8%) and 12 (14.0%) MG patients, respectively. There were 3 (3.5%) MG patients with low bone mass for chronological age. Serum beta C-terminal telopeptide and PTH levels were higher (p < 0.001 and p = 0.001, respectively), and BMD at the femoral neck and trochanter were lower in MG patients (p < 0.001 and p < 0.001, respectively) compared to healthy controls. In patients with MG, grip strength was positively correlated with BMD. Serum 25OHD levels were lower in MG patients than in healthy controls (17.36 ± 6.64 vs. 22.11 ± 7.28 ng/ml, p < 0.001).

CONCLUSION

Grip strength was positively correlated with BMD in Chinese patients with MG. MG patients tended to have low proximal hip BMD, which may partially be explained by reduced muscle strength, vitamin D deficiency, increased PTH levels, and elevated bone resorption markers compared to controls.