Sex‐Dependent,Osteoblast Stage‐Specific Effects of Progesterone Receptor on Bone Acquisition

The role of the progesterone receptor (PR) in the regulation of sexual dimorphism in bone has yet to be determined. Here we utilized genetic fate mapping and Western blotting to demonstrate age‐dependent PR expression in the mouse femoral metaphysis and diaphysis. To define sex‐dependent and osteoblast stage–specific effects of PR on bone acquisition, we selectively deleted PR at different stages of osteoblast differentiation. We found that when Prx1‐Cre mice were crossed with PR floxed mice to generate a mesenchymal stem cell (MSC) conditional KO model (Prx1; PRcKO), the mutant mice developed greater trabecular bone volume with higher mineral apposition rate and bone formation. This may be explained by increased number of MSCs and greater osteogenic potential, particularly in males. Age‐related trabecular bone loss was similar between the Prx1; PRcKO mice and their WT littermates in both sexes. Hormone deficiency during the period of rapid bone growth induced rapid trabecular bone loss in both the WT and the Prx1; PRcKO mice in both sexes. No differences in trabecular bone mass was observed when PR was deleted in mature osteoblasts using osteocalcin‐Cre (Bglap‐Cre). Also, there were no differences in cortical bone mass in all three PRcKO mice. In conclusion, PR inactivation in early osteoprogenitor cells but not in mature osteoblasts influenced trabecular bone accrual in a sex‐dependent manner. PR deletion in osteoblast lineage cells did not affect cortical bone mass. © 2017 American Society for Bone and Mineral Research.     

IGF‐1 Receptor Expression on Circulating Osteoblast Progenitor Cells Predicts Tissue‐Based Bone Formation Rate and Response to Teriparatide in Premenopausal Women With Idiopathic Osteoporosis

We have previously reported that premenopausal women with idiopathic osteoporosis (IOP) have profound microarchitectural deficiencies and heterogeneous bone remodeling. Those with the lowest bone formation rate have higher baseline serum insulin‐like growth factor‐1 (IGF‐1) levels and less robust response to teriparatide. Because IGF‐1 stimulates bone formation and is critical for teriparatide action on osteoblasts, these findings suggest a state of IGF‐1 resistance in some IOP women. To further investigate the hypothesis that osteoblast and IGF‐1‐related mechanisms mediate differential responsiveness to teriparatide in IOP, we studied circulating osteoblast progenitor (COP) cells and their IGF‐1 receptor (IGF‐1R) expression. In premenopausal women with IOP, peripheral blood mononuclear cells (PBMCs) were obtained at baseline (n = 25) and over 24 months of teriparatide treatment (n = 11). Flow cytometry was used to identify and quantify COPs (non‐hematopoetic lineage cells expressing osteocalcin and RUNX2) and to quantify IGF‐1R expression levels. At baseline, both the percent of PBMCs that were COPs (%COP) and COP cell‐surface IGF‐1R expression correlated directly with several histomorphometric indices of bone formation in tetracycline‐labeled transiliac biopsies. In treated subjects, both %COP and IGF‐1R expression increased promptly after teriparatide, returning toward baseline by 18 months. Although neither baseline %COP nor increase in %COP after 3 months predicted the bone mineral density (BMD) response to teriparatide, the percent increase in IGF‐1R expression on COPs at 3 months correlated directly with the BMD response to teriparatide. Additionally, lower IGF‐1R expression after teriparatide was associated with higher body fat, suggesting links between teriparatide resistance, body composition, and the GH/IGF‐1 axis. In conclusion, these assays may be useful to characterize bone remodeling noninvasively and may serve to predict early response to teriparatide and possibly other bone formation–stimulating medications. These new tools may also have utility in the mechanistic investigation of teriparatide resistance in premenopausal IOP and perhaps in other populations. © 2017 American Society for Bone and Mineral Research.     

Bone Health in Patients With Hematopoietic Disorders of Bone Marrow Origin: Systematic Review and Meta‐ Analysis

Blood cell production and bone homeostasis are physically interlinked systems that exhibit active cross‐talk. We examined how bone health is affected in patients with hematopoietic disorders due to abnormal proliferation of bone marrow cells. The electronic databases Medline, Embase, PubMed, BIOSIS Previews, Web of Science, and Cochrane were searched for studies presenting numerical values for trabecular bone volume or bone mineral density in control and patients with hematopoietic disorders. We identified 5 studies for beta‐thalassemia, 6 for sickle cell anemia, 2 for polycythemia vera and essential thrombocythemia, 3 for chronic myelogenous leukemia, 6 for myelofibrosis, 5 for multiple myeloma, and 4 studies each for systemic mastocytosis, lymphocytic leukemia, and hemochromatosis. The effect of the disease state on bone density was significant and negative for beta‐thalassemia (r = –2.00; 95% confidence interval [CI] –3.41, –0.58; p < 0.005), sickle cell anemia (–0.91; –1.36, –0.47; p < 0.00005), chronic myelogenous leukemia (–0.55; –0.88, –0.22; p < 0005), mastocytosis (–0.99; –1.16, –0.82; p < 0.00001), lymphoblastic leukemia (–0.69; –0.98, –0.40; p < 0.00001), multiple myeloma (–0.67; –0.99, –0.35; p < 0.00005), and hemochromatosis (–1.15; –1.64, –0.66; p < 0.00001). The changes were negative but not significant for polycythemia vera (–0.16; –0.38, 0.05; p = 0.069) and essential thrombocythemia (–0.33; –0.92, 0.26; p = 0.14). In myelofibrosis, disease state was associated with increased bone density (0.74; 0.12, 1.36; p < 0.05). Bone density change significantly and negatively correlated with the level of ferritin and bone marrow cellularity but not with hemoglobin or erythropoietin. Thus, independent of hematopoietic lineage, abnormal proliferation of bone marrow cells appears to be associated with bone loss. Iron metabolism may independently contribute to bone homeostasis. © 2016 American Society for Bone and Mineral Research.     

Immediate Initiation of Antiretroviral Therapy for HIV Infection Accelerates Bone Loss Relative to Deferring Therapy: Findings from the START Bone Mineral Density Substudy,a Randomized Trial

Both HIV infection and antiretroviral therapy (ART) are associated with lower bone mineral density (BMD) and increased fracture risk. Because the relative contributions of ART and untreated HIV to BMD loss are unclear, it is important to quantify the effect of ART on bone. We compared the effect of early ART initiation (CD4 >500 cells/μL) with deferred ART on change in BMD in the START Bone Mineral Density substudy, a randomized trial evaluating the effect of immediate ART initiation versus deferring ART (to CD4 <350 cells/μL). BMD was measured annually at the lumbar spine and hip by dual‐energy X‐ray absorptiometry (DXA). Percent change in BMD by treatment assignment (intent‐to‐treat analysis) was estimated using longitudinal mixed models and linear regression. Baseline and follow‐up DXA scans were available for 399 (195 immediate, 204 deferred) participants (median age 32 years, 80% non‐white, 26% women, median CD4 count 642 cells/μL). ART (most commonly including tenofovir and efavirenz) was used for 95% and 18% of follow‐up in the immediate and deferred ART groups, respectively. Through 2.2 years mean follow‐up, immediate ART resulted in greater BMD declines than deferred ART at the hip (–2.5% versus –1.0%; difference –1.5%, 95% confidence interval [CI] –2.2 to –0.8, p < 0.001) and spine (–1.9% versus –0.4%; difference –1.6%, 95% CI –2.2 to –1.0, p < 0.001). BMD declines were greatest in the first year of ART. In the immediate ART group, spine BMD stabilized after year 1, whereas hip BMD declined progressively over 2 years. After year 1, BMD changes were similar in the immediate and deferred groups. No clinical, HIV‐related, or ART characteristic predicted greater BMD loss in either group. All HIV treatment guidelines now recommend ART initiation at HIV diagnosis because of the reduced risk of serious clinical outcomes. Better understanding of the longer‐term consequences of the observed reductions in BMD is needed. Clinical Trials Registration: NCT00867048. © 2017 American Society for Bone and Mineral Research.     

Decreased Quantity and Quality of the Periarticular and Nonperiarticular Bone in Patients With Rheumatoid Arthritis: A Cross‐Sectional HR‐pQCT Study

Rheumatoid arthritis (RA) is a highly bone destructive disease. Although it is well established that RA leads to bone loss and increased fracture risk, current knowledge on the microstructural changes of bone in RA is still limited. The purpose of this study was to assess the microstructure of periarticular and nonperiarticular bone in female and male RA patients and compare it with respective healthy controls. We performed two high‐resolution peripheral quantitative computed tomography (HR‐pQCT; Xtreme‐CT) scans, one of the distal radius and one of the ultradistal radius in 90 patients with RA (60 females, 30 males) and 70 healthy controls (40 females, 30 males) matched for sex, age, and body mass index. Volumetric bone mineral density (vBMD), bone geometry, and bone microstructure including trabecular bone volume fraction (BV/TV), trabecular number (Tb.N), trabecular thickness (Tb.Th), cortical thickness (Ct.Th) and cortical porosity (Ct.Po) were assessed. At the distal and ultradistal radius, trabecular (p = 0.005 and p < 0.001) and cortical BMD (p < 0.001 and p < 0.001) were significantly decreased in male and female patients with RA, respectively. BV/TV was also decreased at both sites, based on lower Tb.N in female RA (p < 0.001 for both sites) and lower Tb.Th (p = 0.034 and p = 0.005) in male RA patients compared with respective healthy controls. Cortical thinning (p = 0.018 and p = 0.002) but not Ct.Po (p = 0.070 and p = 0.275) was pronounced in male and female RA patients at the distal radius. Cortical perimeter was increased in male and female RA patients at both sites. Multiple regression models showed that bone geometry (cortical perimeter) is predominantly influenced by age of the RA patient, cortical thickness by both age and disease duration, and trabecular microstructure predominantly by the disease duration. In summary, these data show profound deterioration of bone microstructure in the appendicular skeleton of RA patients at both periarticular and nonperiarticular sites. © 2014 American Society for Bone and Mineral Research.     

Regulation of Sclerostin Expression in Multiple Myeloma by Dkk‐1: A Potential Therapeutic Strategy for Myeloma Bone Disease

Sclerostin is a potent inhibitor of osteoblastogenesis. Interestingly, newly diagnosed multiple myeloma (MM) patients have high levels of circulating sclerostin that correlate with disease stage and fractures. However, the source and impact of sclerostin in MM remains to be defined. Our goal was to determine the role of sclerostin in the biology of MM and its bone microenvironment as well as investigate the effect of targeting sclerostin with a neutralizing antibody (scl‐Ab) in MM bone disease. Here we confirm increased sclerostin levels in MM compared with precursor disease states like monoclonal gammopathy of undetermined significance (MGUS) and smoldering MM. Furthermore, we found that a humanized MM xenograft mouse model bearing human MM cells (NOD‐SCID.CB17 male mice injected intravenously with 2.5 million of MM1.S‐Luc‐GFP cells) demonstrated significantly higher concentrations of mouse‐derived sclerostin, suggesting a microenvironmental source of sclerostin. Associated with the increased sclerostin levels, activated β‐catenin expression levels were lower than normal in MM mouse bone marrow. Importantly, a high‐affinity grade scl‐Ab reversed osteolytic bone disease in this animal model. Because scl‐Ab did not demonstrate significant in vitro anti‐MM activity, we combined it with the proteasome inhibitor carfilzomib. Our data demonstrated that this combination therapy significantly inhibited tumor burden and improved bone disease in our in vivo MM mouse model. In agreement with our in vivo data, sclerostin expression was noted in marrow stromal cells and osteoblasts of MM patient bone marrow samples. Moreover, MM cells stimulated sclerostin expression in immature osteoblasts while inhibiting osteoblast differentiation in vitro. This was in part regulated by Dkk‐1 secreted by MM cells and is a potential mechanism contributing to the osteoblast dysfunction noted in MM. Our data confirm the role of sclerostin as a potential therapeutic target in MM bone disease and provides the rationale for studying scl‐Ab combined with proteasome inhibitors in MM. © 2016 American Society for Bone and Mineral Research.     

Alterations of Bone Density,Microstructure, and Strength of the Distal Radius in Male Patients With Rheumatoid Arthritis: A Case‐Control Study With HR‐pQCT

In this cross‐sectional study, we investigated volumetric bone mineral density (vBMD), bone microstructure, and biomechanical competence of the distal radius in male patients with rheumatoid arthritis (RA). The study cohort comprised 50 male RA patients of average age of 61.1 years and 50 age‐matched healthy males. Areal BMD (aBMD) of the hip, lumbar spine, and distal radius was measured by dual‐energy X‐ray absorptiometry. High‐resolution peripheral quantitative computed tomography (HR‐pQCT) of the distal radius provided measures of cortical and trabecular vBMD, microstructure, and biomechanical indices. aBMD of the hip but not the lumbar spine or ultradistal radius was significantly lower in RA patients than controls after adjustment for body weight. Total, cortical, and trabecular vBMD at the distal radius were, on average, –3.9% to –23.2% significantly lower in RA patients, and these differences were not affected by adjustment for body weight, testosterone level, or aBMD at the ultradistal radius. Trabecular microstructure indices were, on average, –8.1% (trabecular number) to 28.7% (trabecular network inhomogeneity) significantly inferior, whereas cortical pore volume and cortical porosity index were, on average, 80.3% and 63.9%, respectively, significantly higher in RA patients. RA patients also had significantly lower whole‐bone stiffness, modulus, and failure load, with lower and more unevenly distributed cortical and trabecular stress. Density and microstructure indices significantly correlated with disease activity, severity, and levels of pro‐inflammatory cytokines (interleukin [IL] 12p70, tumor necrosis factor, IL‐6 and IL‐1β). Ten RA patients had focal periosteal bone apposition most prominent at the ulnovolar aspect of the distal radius. These patients had shorter disease duration and significantly higher cortical porosity. In conclusion, HR‐pQCT reveals significant alterations of bone density, microstructure, and strength of the distal radius in male RA patients and provides new insight into the microstructural basis of bone fragility accompanying chronic inflammation. © 2014 American Society for Bone and Mineral Research.     

Type 2 Diabetes Mellitus Is Associated With Better Bone Microarchitecture But Lower Bone Material Strength and Poorer Physical Function in Elderly Women: A Population‐Based Study

Type 2 diabetes mellitus (T2DM) is associated with an increased risk of fractures according to several studies. The underlying mechanisms remain unclear, although small case‐control studies indicate poor quality of the cortical bone. We have studied a population‐based sample of women aged 75 to 80 years in Gothenburg, randomly invited from the population register. Areal bone mineral density (aBMD) was measured by dual‐energy X‐ray absorptiometry (Hologic Discovery A), bone microarchitecture by high‐resolution peripheral quantitative computed tomography (HR‐pQCT; ExtremeCT from Scanco Medical AG), and reference point indentation was performed with Osteoprobe (Active Life Scientific). Women with T2DM (n = 99) had higher aBMD compared to controls (n = 954). Ultradistal tibial and radial trabecular bone volume fraction (+11% and +15%, respectively), distal cortical volumetric BMD (+1.6% and +1.7%), cortical area (+11.5% and +9.3%), and failure load (+7.7% and +12.9%) were higher in diabetics than in controls. Cortical porosity was lower (mean ± SD: 1.5% ± 1.1% versus 2.0% ± 1.7%, p = 0.001) in T2DM in the distal radius but not in the ultradistal radius or the tibia. Adjustment for covariates (age, body mass index, glucocorticoid treatment, smoking, physical activity, calcium intake, bone‐active drugs) eliminated the differences in aBMD but not in HR‐pQCT bone variables. However, bone material strength index (BMSi) by reference point indentation was lower in T2DM (74.6 ± 7.6 versus 78.2 ± 7.5, p < 0.01), also after adjustment, and women with T2DM performed clearly worse in measures of physical function (one leg standing: –26%, 30‐s chair‐stand test: –7%, timed up and go: +12%, walking speed: +8%; p < 0.05‐0.001) compared to controls. In conclusion, we observed a more favorable bone microarchitecture but no difference in adjusted aBMD in elderly women with T2DM in the population compared to nondiabetics. Reduced BMSi and impaired physical function may explain the increased fracture risk in T2DM. © 2016 American Society for Bone and Mineral Research.     

Adverse Effects of Osteocytic Constitutive Activation of ß‐Catenin on Bone Strength and Bone Growth

The activation of the canonical Wnt/β‐catenin signaling pathway in both mesenchymal stem cells and osteoblasts has been demonstrated to increase bone mass, showing promise for the treatment of low bone volume conditions such as osteoporosis. However, the possible side effects of manipulating this pathway have not been fully addressed. Previously, we reported that the constitutive activation of ß‐catenin in osteoblasts impaired vertebral linear growth. In the present study, β‐catenin was constitutively activated in osteocytes by crossing Catnb+/lox(exon 3) mice with dentin matrix protein 1(DMP1)‐Cre transgenic mice, and the effects of this activation on bone mass, bone growth and bone strength were then observed. DMP1‐Cre was found to be predominantly expressed in osteocytes, with weak expression in a small portion of osteoblasts and growth plate chondrocytes. After the activation, the cancellous bone mass was dramatically increased, almost filling the entire bone marrow cavity in long bones. However, bone strength decreased significantly. Thinner and more porous cortical bone along with impaired mineralization were responsible for the decrease in bone strength. Furthermore, the mice showed shorter stature with impaired linear growth of the long bones. Moreover, the concentration of serum phosphate decreased significantly after the activation of ß‐catenin, and a high inorganic phosphate (Pi) diet could partially rescue the phenotype of decreased mineralization level and impaired linear growth. Taken together, the constitutive activation of β‐catenin in osteocytes may increase cancellous bone mass; however, the activation also had adverse effects on bone strength and bone growth. These adverse effects should be addressed before the adoption of any therapeutic clinical application involving adjustment of the Wnt/β‐catenin signaling pathway. © 2015 American Society for Bone and Mineral Research.     

Effect of Two‐Year Caloric Restriction on Bone Metabolism and Bone Mineral Density in Non‐Obese Younger Adults: A Randomized Clinical Trial

Although caloric restriction (CR) could delay biologic aging in humans, it is unclear if this would occur at the cost of significant bone loss. We evaluated the effect of prolonged CR on bone metabolism and bone mineral density (BMD) in healthy younger adults. Two‐hundred eighteen non‐obese (body mass index [BMI] 25.1 ± 1.7 kg/m²), younger (age 37.9 ± 7.2 years) adults were randomly assigned to 25% CR (CR group, n = 143) or ad libitum (AL group, n = 75) for 2 years. Main outcomes were BMD and markers of bone turnover. Other outcomes included body composition, bone‐active hormones, nutrient intake, and physical activity. Body weight (–7.5 ± 0.4 versus 0.1 ± 0.5 kg), fat mass (–5.3 ± 0.3 versus 0.4 ± 0.4 kg), and fat‐free mass (–2.2 ± 0.2 versus –0.2 ± 0.2 kg) decreased in the CR group compared with AL (all between group p < 0.001). Compared with AL, the CR group had greater changes in BMD at 24 months: lumbar spine (–0.013 ± 0.003 versus 0.007 ± 0.004 g/cm²; p < 0.001), total hip (–0.017 ± 0.002 versus 0.001 ± 0.003 g/cm²; p < 0.001), and femoral neck (–0.015 ± 0.003 versus –0.005 ± 0.004 g/cm²; p = 0.03). Changes in bone markers were greater at 12 months for C‐telopeptide (0.098 ± 0.012 versus 0.025 ± 0.015 μg/L; p < 0.001), tartrate‐resistant acid phosphatase (0.4 ± 0.1 versus 0.2 ± 0.1 U/L; p = 0.004), and bone‐specific alkaline phosphatase (BSAP) (–1.4 ± 0.4 versus –0.3 ± 0.5 U/L; p = 0.047) but not procollagen type 1 N‐propeptide; at 24 months, only BSAP differed between groups (–1.5 ± 0.4 versus 0.9 ± 0.6 U/L; p = 0.001). The CR group had larger increases in 25‐hydroxyvitamin D, cortisol, and adiponectin and decreases in leptin and insulin compared with AL. However, parathyroid hormone and IGF‐1 levels did not differ between groups. The CR group also had lower levels of physical activity. Multiple regression analyses revealed that body composition, hormones, nutrients, and physical activity changes explained ～31% of the variance in BMD and bone marker changes in the CR group. Therefore, bone loss at clinically important sites of osteoporotic fractures represents a potential limitation of prolonged CR for extending life span. Further long‐term studies are needed to determine if CR‐induced bone loss in healthy adults contributes to fracture risk and if bone loss can be prevented with exercise. © 2015 American Society for Bone and Mineral Research.     

Relationship Between Pretreatment Rate of Bone Loss and Bone Density Response to Once‐Yearly ZOL: HORIZON‐PFT Extension Study

Several studies have shown that high bone turnover is associated with greater rates of bone loss and greater bone mineral density (BMD) response to antiresorptive therapy in postmenopausal osteoporosis. However, it is not known whether greater rates of bone loss before therapy are associated with greater BMD response to antiresorptive therapy. In the HORIZON‐PFT study and its extension, one group of women who were randomized to receive placebo for 3 years (years 1, 2, and 3) were then switched to zoledronic acid (ZOL) 5 mg annually for up to three injections (years 4, 5, and 6, P3Z3 arm) (n = 1223). We measured total hip BMD at baseline, 1, 2, and 3 years on placebo and at 4.5 and 6 years on ZOL. The procollagen type I N‐terminal propeptide (PINP) was measured at 3, 4.5, and 6 years. By design, not all subjects were followed for as long as 6 years, so this analysis focused on the results at 4.5 years. Those with the largest loss in total hip BMD on placebo in years 0 to 3 had the largest gain during ZOL (years 3 to 4.5): (r = –0.39, p < 0.0001). The change in total hip BMD in years 0 to 3 on placebo was related to the serum PINP at the end of the 3‐year period (r = –0.24, p < 0.0001). The change in total hip BMD on ZOL from year 3 to 4.5 was related to the serum PINP at the end of the 3‐year period (r = 0.26, p < 0.0001). We conclude that BMD response to ZOL is greater in postmenopausal women who had larger loss before treatment. This association may result from higher bone turnover being associated with both greater bone loss on placebo and greater BMD response to ZOL. © 2014 American Society for Bone and Mineral Research.     

Parathyroid Hormone 1‐84 Targets Bone Vascular Structure and Perfusion in Mice: Impacts of Its Administration Regimen and of Ovariectomy

Bone vessel functions during bone remodeling are poorly understood. They depend on both vessel network structure and vasomotor regulation. Parathyroid hormone (PTH) is a systemic vasodilator that may modulate microvascularization. Moreover, although intermittent PTH is anti‐osteoporotic, continuous PTH administration can be catabolic for bone. Finally, ovariectomy (OVX) reduces bone perfusion and vessel density in mice. We reasoned that the effects of PTH on bone vascularization might depend on its administration regimen and be impacted by ovariectomy. A 100‐µg/kg PTH 1‐84 daily dose was administered for 15 days to 4‐month‐old female C57BL/6 mice, either as daily sc injection (iPTH) or continuously (cPTH; ALZET minipump). Blood pressure (BP) and tibia bone perfusion were measured in vivo with a laser Doppler device. Histomorphometry of bone and barium‐contrasted vascular network were performed on the same tibia. Compared with untreated controls, both iPTH and cPTH increased bone formation but had opposite effects on resorption. Both iPTH and cPTH were slightly angiogenic. Intermittent PTH increased microvessel size (+48%, p < 0.001), whereas cPTH decreased it (–29%, p = 0.009). iPTH increased bone perfusion (27%, p < 0.001) with no change in BP, whereas cPTH did not. The vascular effects of a 15‐day iPTH treatment were analyzed in OVX mice and compared with sham‐operated and OVX untreated controls. Two other anti‐osteoporotic drugs, zoledronate (one injection, 70 µg/kg) and propranolol, (5 mg/kg/d) were tested in OVX mice. Although no change in bone mass was observed, iPTH stimulated bone formation and prevented the OVX‐induced reduction in bone perfusion and vessel density. Both zoledronate and propranolol strongly lowered bone turnover, but surprisingly, zoledronate prevented OVX‐induced reduction in bone perfusion but propranolol did not. Our integrative approach thus demonstrates that the effects of PTH on bone vessel structure and function depend on its mode of administration as well as on the HPG‐axis hormonal status, and that OVX‐induced vascular changes are prevented by iPTH. © 2014 American Society for Bone and Mineral Research.     

Relationship Between Low Bone Mineral Density and Fractures With Incident Cardiovascular Disease: A Systematic Review and Meta‐Analysis

An increasing evidence base suggests that low bone mineral density (BMD) and fractures are associated with cardiovascular disease (CVD). We conducted a systematic review and meta‐analysis summarizing the evidence of low BMD and fractures as risk factors for future CVD. Two independent authors searched major databases from inception to August 1, 2016, for longitudinal studies reporting data on CVD incidence (overall and specific CVD) and BMD status and fractures. The association between low BMD, fractures, and CVD across longitudinal studies was explored by calculating pooled adjusted hazard ratios (HRs) ±95% confidence intervals (CIs) with a random‐effects meta‐analysis. Twenty‐eight studies (18 regarding BMD and 10 fractures) followed a total of 1,107,885 participants for a median of 5 years. Taking those with higher BMD as the reference, people with low BMD were at increased risk of developing CVD during follow‐up (11 studies; HR = 1.33; 95%CI, 1.27 to 1.38; I² = 53%), after adjusting for a median of eight confounders. This finding was confirmed using a decrease in one standard deviation of baseline BMD (9 studies; HR = 1.16; 95% CI, 1.09 to 1.24; I² = 69%). The presence of fractures at baseline was associated with an increased risk of developing CVD (HR = 1.20; 95% CI, 1.06 to 1.37; I² = 91%). Regarding specific CVDs, low BMD was associated with an increased risk of developing coronary artery disease, cerebrovascular conditions, and CVD‐associated death. Fractures at baseline was associated with an increased risk of cerebrovascular conditions and death due to CVD. In conclusion, low BMD and fractures are associated with a small, but significant increased risk of CVD risk and possibly death. © 2017 American Society for Bone and Mineral Research.     

Examining the effects of HIV self‐testing compared to standard HIV testing services: a systematic review and meta‐analysis

Introduction : HIV self‐testing (HIVST) is a discreet and convenient way to reach people with HIV who do not know their status, including many who may not otherwise test. To inform World Health Organization (WHO) guidance, we assessed the effect of HIVST on uptake and frequency of testing, as well as identification of HIV‐positive persons, linkage to care, social harm, and risk behaviour. Methods : We systematically searched for studies comparing HIVST to standard HIV testing until 1 June 2016. Meta‐analyses of studies reporting comparable outcomes were conducted using a random‐effects model for relative risks (RR) and 95% confidence intervals. The quality of evidence was evaluated using GRADE. Results : After screening 638 citations, we identified five randomized controlled trials (RCTs) comparing HIVST to standard HIV testing services among 4,145 total participants from four countries. All offered free oral‐fluid rapid tests for HIVST and were among men. Meta‐analysis of three RCTs showed HIVST doubled uptake of testing among men (RR = 2.12; 95% CI: 1.51, 2.98). Meta‐analysis of two RCTs among men who have sex with men showed frequency of testing nearly doubled (Rate ratio = 1.88; 95% CI: 1.17; 3.01), resulting in two more tests in a 12–15‐month period (Mean difference = 2.13; 95% CI: 1.59, 2.66). Meta‐analysis of two RCTs showed HIVST also doubled the likelihood of an HIV‐positive diagnosis (RR = 2.02; 95% CI: 0.37, 10.76, 5.32). Across all RCTs, there was no indication of harm attributable to HIVST and potential increases in risk‐taking behaviour appeared to be minimal. Conclusions : HIVST is associated with increased uptake and frequency of testing in RCTs. Such increases, particularly among those at risk who may not otherwise test, will likely identify more HIV‐positive individuals as compared to standard testing services alone. However, further research on how to support linkage to confirmatory testing, prevention, treatment and care services is needed. WHO now recommends HIVST as an additional HIV testing approach.     

Associations of 25‐Hydroxyvitamin D and 1,25‐Dihydroxyvitamin D With Bone Mineral Density,Bone Mineral Density Change,and Incident Nonvertebral Fracture

Relationships between 1,25‐dihydroxyvitamin D (1,25(OH)₂D) and skeletal outcomes are uncertain. We examined the associations of 1,25(OH)₂D with bone mineral density (BMD), BMD change, and incident non‐vertebral fractures in a cohort of older men and compared them with those of 25‐hydroxyvitamin D (25OHD). The study population included 1000 men (aged 74.6 ± 6.2 years) in the Osteoporotic Fractures in Men (MrOS) study, of which 537 men had longitudinal dual‐energy X‐ray absorptiometry (DXA) data (4.5 years of follow‐up). A case‐cohort design and Cox proportional hazards models were used to test the association between vitamin D metabolite levels and incident nonvertebral and hip fractures. Linear regression models were used to estimate the association between vitamin D measures and baseline BMD and BMD change. Interactions between 25OHD and 1,25(OH)₂D were tested for each outcome. Over an average follow‐up of 5.1 years, 432 men experienced incident nonvertebral fractures, including 81 hip fractures. Higher 25OHD was associated with higher baseline BMD, slower BMD loss, and lower hip fracture risk. Conversely, men with higher 1,25(OH)₂D had lower baseline BMD. 1,25(OH)₂D was not associated with BMD loss or nonvertebral fracture. Compared with higher levels of calcitriol, the risk of hip fracture was higher in men with the lowest 1,25(OH)₂D levels (8.70 to 51.60 pg/mL) after adjustment for baseline hip BMD (hazard ratio [HR] = 1.99, 95% confidence interval [CI] 1.19–3.33). Adjustment of 1,25(OH)₂D data for 25OHD (and vice versa) had little effect on the associations observed but did attenuate the hip fracture association of both vitamin D metabolites. In older men, higher 1,25(OH)₂D was associated with lower baseline BMD but was not related to the rate of bone loss or nonvertebral fracture risk. However, with BMD adjustment, a protective association for hip fracture was found with higher 1,25(OH)₂D. The associations of 25OHD with skeletal outcomes were generally stronger than those for 1,25(OH)₂D. These results do not support the hypothesis that measures of 1,25(OH)₂D improve the ability to predict adverse skeletal outcomes when 25OHD measures are available. © 2015 American Society for Bone and Mineral Research.