Abdominal aortic calcification and the risk of bone fractures: a meta-analysis of prospective cohort studies

Arterial stiffness and risk of new-onset fragility fracture in Chinese men and women: The Kailuan cohort study

BACKGROUND

Previous studies have shown an association between increased arterial stiffness and reduced bone mineral density. However, the relationship between arterial stiffness and fragility fracture remains unclear. In this study, we explored the impact of arterial stiffness on the risk of new-onset fragility fracture.

METHODS

The study included 53,107 participants in the Kailuan Study in whom brachial-ankle pulse wave velocity (baPWV) measurements were obtained between 2010 and 2021. All participants were free of fragility fractures at baseline. A Cox proportional hazard regression model was used to estimate the hazard ratio (HR) and 95 % confidence interval (CI) for incident fragility fracture on the baseline baPWV groups: <1400 cm/s (reference), 1400 ≤ baPWV < 1800 cm/s, and ≥1800 cm/s.

RESULTS

In total, 327 incident fragility fractures were recorded during an average follow-up of 4.99 ± 3.02 years. After adjustment for potential confounders, the HR for the risk of new-onset fragility fracture was 1.66 (95 % CI 1.14-2.42) for the arterial stiffness group in comparison with the normal baPWV group. The risk of fragility fracture was higher in men (HR 1.64, 95 % CI 1.05-2.57). There was a linear association between higher baPWV and fragility fracture.

CONCLUSIONS

Arterial stiffness as measured by baPWV was associated with the risk of fragility fracture.

A Novel Quantitative Computer-Assisted Score Can Improve Repeatability in the Estimate of Vascular Calcifications at the Abdominal Aorta

In CKD and in the elderly, Vascular Calcifications (VC) are associated to cardiovascular events and bone fractures. VC scores at the abdominal aorta (AA) from lateral spine radiographs are widely applied (the 0-24 semiquantitative discrete visual score (SV) being the most used). We hypothesised that a novel continuum score based on quantitative computer-assisted tracking of calcifications (QC score) can improve the precision of the SV score. This study tested the repeatability and reproducibility of QC score and SV score. In forty-four patients with VC from an earlier study, five experts from four specialties evaluated the data twice using a dedicated software. Test-retest was performed on eight subjects. QC results were reported in a 0-24 scale to readily compare with SV. The QC score showed higher intra-operator repeatability: the 95% CI of Bland-Altman differences was almost halved in QC; intra-operator R2 improved from 0.67 for SV to 0.79 for QC. Inter-observer repeatability was higher for QC score in the first (Intraclass Correlation Coefficient 0.78 vs. 0.64), but not in the second evaluation (0.84 vs. 0.82), indicating a possible heavier learning artefact for SV. The Minimum Detectable Difference (MDD) was smaller for QC (2.98 vs. 4 for SV, in the 0-24 range). Both scores were insensitive to test-retest procedure. Notably, QC and SV scores were discordant: SV showed generally higher values, and an increasing trend of differences with VC severity. In summary, the new QC score improved the precision of lateral spine radiograph scores in estimating VC. We reported for the first time an estimate of MDD in VC assessment that was 25% lower for the new QC score with respect to the usual SV score. An ongoing study will determine whether this lower MDD may reduce follow-up times to check for VC progression.

Abdominal aortic calcification, bone mineral density and fractures: a systematic review and meta-analysis of observational studies

BACKGROUND

Abdominal aortic calcification (AAC) has been inconsistently associated with skeletal health. We aimed to investigate the association of AAC with bone mineral density (BMD) and fracture risk by pooling the findings of observational studies.

METHODS

Medline, EMBASE, Web of Science and Google Scholar were searched (August 2021). All clinical studies that assessed the association between AAC and BMD or fracture were included. AAC was categorized into any/advanced (all higher reported groups) vs no/less advanced (lowest reported group). Pooled standardized mean differences (SMDs) and risk ratios (RRs) with 95% confidence intervals (CI) were determined for BMD and fracture, respectively, using random-effects models.

RESULTS

Of 2,192 articles screened, 86 (61,553 participants) were included in the review, while 42 provided data for meta-analysis. AAC was associated with lower BMD at the total hip [SMD=-1.05 (95%CI: -1.47 to -0.63); 16 studies], femoral neck [-0.25 (-0.46 to - 0.04); 10] and lumbar spine [-0.67 (-1.21 to -0.12); 20]. AAC was associated with a greater risk of any fracture [RR= 1.73 (95%CI: 1.48 to 2.02); 27]. AAC was also associated with vertebral, non-vertebral and hip fractures. In dose-response analysis, the highest AAC group had greater risks of any, vertebral and non-vertebral fractures.

CONCLUSIONS

AAC is associated with lower BMD and increased fracture risk at multiple sites, underscoring the potential importance of vascular disease on skeletal health. Detection of AAC at the time of BMD testing may provide clinicians with prognostic information about bone health to enhance osteoporosis screening programs and fracture risk prediction.

Skeletal and extraskeletal disorders of biomineralization

The physiological process of biomineralization is complex and deviation from it leads to a variety of diseases. Progress in the past 10 years has enhanced understanding of the genetic, molecular and cellular pathophysiology underlying these disorders; sometimes, this knowledge has both facilitated restoration of health and clarified the very nature of biomineralization as it occurs in humans. In this Review, we consider the principal regulators of mineralization and crystallization, and how dysregulation of these processes can lead to human disease. The knowledge acquired to date and gaps still to be filled are highlighted. The disorders of mineralization discussed comprise a broad spectrum of conditions that encompass bone disorders associated with alterations of mineral quantity and quality, as well as disorders of extraskeletal mineralization (hyperphosphataemic familial tumoural calcinosis). Included are disorders of alkaline phosphatase (hypophosphatasia) and phosphate homeostasis (X-linked hypophosphataemic rickets, fluorosis, rickets and osteomalacia). Furthermore, crystallopathies are covered as well as arterial and renal calcification. This Review discusses the current knowledge of biomineralization derived from basic and clinical research and points to future studies that will lead to new therapeutic approaches for biomineralization disorders.

Relationship between blood cadmium and abdominal aortic calcification: NHANES 2013-2014

BACKGROUND

Cadmium is a common toxic heavy metal in the environment and can cause irreversible damage to the human body. It is well established that cadmium has direct cardiovascular toxicity, but the relationship between cadmium exposure and abdominal aortic calcification (AAC) is not clear.

METHODS

This was a cross-sectional study that aimed to assess the relationship between blood cadmium (B-Cd) and AAC in U.S. adults ≥ 40 years old. We obtained data from the 2013-2014 National Health and Nutrition Examination Survey. The AAC score was quantified by the Kauppila score system, whereas severe AAC was defined as an AAC score ≥ 6. We performed multivariate regressions, correlated subgroup analyses, and interaction terms to evaluate the relationship between B-Cd and AAC score and severe AAC.

RESULTS

For 1530 enrolled participants, the mean AAC score was 1.52 ± 3.32, and the prevalence of severe AAC was 8.95%. Participants with higher B-Cd levels showed higher AAC scores (β = 0.36, 95% CI: 0.03, 0.70, P = 0.0323) and an increased risk of severe AAC (OR=1.61, 95% CI: 1.01, 2.56, P = 0.0432). However, these associations were weakened after adjusting for serum cotinine to define smoking exposure. Subgroup analyses and correlated interaction terms indicated that the relationship between B-Cd and AAC was generally similar in different population settings, except for males, nonsmokers, and participants with a normal body mass index (BMI). The interaction terms indicated that smoking exposure status defined by serum cotinine interacted with the relationship between B-Cd and AAC condition (P for interaction=0.0413).

CONCLUSIONS

There might be positive associations between B-Cd levels and AAC scores and the risk of severe AAC, while these associations were partially explained by smoking exposure. However, more well-designed studies are still needed to validate this relationship.

Machine learning for automated abdominal aortic calcification scoring of DXA vertebral fracture assessment images: A pilot study

BACKGROUND

Abdominal aortic calcification (AAC) identified on dual-energy x-ray absorptiometry (DXA) vertebral fracture assessment (VFA) lateral spine images is predictive of cardiovascular outcomes, but is time-consuming to perform manually. Whether this procedure can be automated using convolutional neural networks (CNNs), a class of machine learning algorithms used for image processing, has not been widely investigated.

METHODS

Using the Province of Manitoba Bone Density Program DXA database, we selected a random sample of 1100 VFA images from individuals qualifying for VFA as part of their osteoporosis assessment. For each scan, AAC was manually scored using the 24-point semi-quantitative scale and categorized as low (score < 2), moderate (score 2 to <6), or high (score ≥ 6). An ensemble consisting of two CNNs was developed, by training and evaluating separately on single-energy and dual-energy images. AAC prediction was performed using the mean AAC score of the two models.

RESULTS

Mean (SD) age of the cohort was 75.5 (6.7) years, 95.5% were female. Training (N = 770, 70%), validation (N = 110, 10%) and test sets (N = 220, 20%) were well-balanced with respect to baseline characteristics and AAC scores. For the test set, the Pearson correlation between the CNN-predicted and human-labelled scores was 0.93 with intraclass correlation coefficient for absolute agreement 0.91 (95% CI 0.89-0.93). Kappa for AAC category agreement (prevalence- and bias-adjusted, ordinal scale) was 0.71 (95% CI 0.65-0.78). There was complete separation of the low and high categories, without any low AAC score scans predicted to be high and vice versa.

CONCLUSIONS

CNNs are capable of detecting AAC in VFA images, with high correlation between the human and predicted scores. These preliminary results suggest CNNs are a promising method for automatically detecting and quantifying AAC.

Ascending Aortic Calcification as a Potential Predictor for Low Bone Mineral Density: A Pilot Study

BACKGROUND

Identifying the factors related to low bone mineral density (BMD) can have significant implications for preventing hip fractures. The correlation between ascending aortic calcification and BMD has never been reported. Therefore, the purpose of the current study is to confirm the hypothesis that ascending aortic calcification can be used as a predictive factor for low BMD and to find a radiographic sign to show it.

METHOD

Plain film and computed tomography (CT) images of the thorax were obtained from 91 patients with hip fractures. Using the images, the calcification line of the ascending aorta adjacent to the aortic arch was evaluated. A prominent calcification line confirmed by both plain film and CT was classified as +2. A line which was ambiguous on plain film but confirmed by CT was classified as +1. Cases with no calcification were categorized as 0 (control). We compared the classified score with the BMD and calculated the kappa coefficient to measure intraobserver reliabilities for this radiographic finding.

RESULTS

Twenty-eight patients showed a +2 line, twenty-four patients showed a +1 line, and thirty-nine patients showed 0 lines. The median BMD of each group was 0.37 for the +2 line, 0.45 for the +1 line, and 0.51 for the 0 line. The BMD for the +2 group was significantly lower than the others. The kappa coefficient was approximately 0.6 (p < 0.01).

CONCLUSION

The imaging finding of calcification of the ascending aorta might be considered as a potential surrogate marker of low BMD. In such subjects, BMD might be ordered for the confirmation of diagnosis of osteoporosis. Mini-Abstract. The Aortic Arch Tail Sign, a calcification line on the ascending aorta, was relevant to low BMD in the current study. BMD can be ordered for the confirmation of diagnosis of osteoporosis in a subject incidentally found to have ascending aorta calcification on X-ray or CT.

Joint Associations of Prevalent Radiographic Vertebral Fracture and Abdominal Aortic Calcification With Incident Hip, Major Osteoporotic, and Clinical Vertebral Fractures

Prevalent vertebral fractures (PVFx) and abdominal aortic calcification (AAC) are both associated with incident fractures and can be ascertained on the same lateral spine images, but their joint association with incident fractures is unclear. Our objective was to estimate the individual and joint associations of PVFx and AAC with incident major osteoporotic, hip, and clinical vertebral fractures in 5365 older men enrolled in the Osteoporotic Fractures in Men (MrOS) Study, using Cox proportional hazards and Fine and Gray subdistribution hazards models to account for competing mortality. PVFx (Genant SQ grade 2 or 3) and 24-point AAC score were ascertained on baseline lateral spine radiographs. Self-reports of incident fractures were solicited every 4 months and confirmed by review of clinical radiographic reports. Compared with men without PVFx and AAC-24 score 0 or 1, the subdistribution hazard ratio (SHR) for incident major osteoporotic fracture was 1.38 (95% confidence interval [CI] 1.13-1.69) among men with AAC-24 score ≥2 alone, 1.71 (95% CI 1.37-2.14) for men with PVFx alone, and 2.35 (95% CI 1.75-3.16) for men with both risk factors, after accounting for conventional risk factors and competing mortality. Wald statistics showed improved prediction model performance by including both risk factors compared with including only AAC (chi-square = 17.3, p < .001) or including only PVFx (chi-square = 8.5, p = .036). Older men with both PVFx and a high level of AAC are at higher risk of incident major osteoporotic fracture than men with either risk factor alone. Assessing prevalent radiographic vertebral fracture and AAC on the same lateral spine images may improve prediction of older men who will have an incident major osteoporotic fracture, even after accounting for traditional fracture risk factors and competing mortality. © 2021 American Society for Bone and Mineral Research (ASBMR).

Brachial-ankle pulse wave velocity is associated with the risk of osteoporosis: a cross-sectional evidence from a Chinese community-based cohort

Background

Association of arterial stiffness and osteoporosis has been well documented in elderly population. However, it is not clear whether they co-progress from the early stages through common mechanisms. The object of this study was to evaluate possible associations between arterial stiffness and osteoporosis by measuring brachial-ankle pulse wave velocity (baPWV) and the Osteoporosis Self-Assessment Tool for Asia (OSTA) index among a healthy population of Chinese aged 40 years and older. Whether baPWV can be used as a predictor of osteoporosis on OSTA was further assessed.

Methods

This study was cross-sectional in design. Of 3984 adults aged 40 years and older in the Yunyan district of Guiyang (Guizhou, China) who underwent both OSTA and baPWV measurements within 1 month, 1407 were deemed eligible for inclusion (women, 1088; men, 319).

Results

The mean baPWV was 1475 ± 302 cm/s (range,766–3459 cm/s). baPWV in 110 individuals with high risk of osteoporosis (OSTA index < − 4) was higher than that of individuals with non-high risk (1733 ± 461 cm/s vs. 1447 ± 304 cm/s, P < 0.001). OSTA index was negatively correlated with baPWV(ρ = − 0.296, P < 0.001) after adjusting for age, sex, body mass index, waist circumference, diastolic blood pressure, and creatinine clearance rate. baPWV was an independent predictor for the presence of high risk of osteoporosis (β = − 0.001, P < 0.001) and was consistent across age and sex subgroups, and the optimal baPWV cutoff value for predicting the presence of high risk of osteoporosis and fracture was 1693 cm/s. The AUC was 0.722 (95% confidence interval [CI], 0.667–0.777; P < 0.001, sensitivity of 52.8% and specificity of 83.6%).

Conclusions

We conclude that arterial stiffness measured by baPWV is well correlated with the severity of osteoporosis evaluated by OSTA. baPWV index may be a valuable tool for identifying individuals with risk of developing osteoporosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-020-02125-3.

Relationship of volumetric bone mineral density by quantitative computed tomography with abdominal aortic calcification

OBJECTIVE

This multicenter study aimed to evaluate the association between volumetric bone mineral density (vBMD) and abdominal aortic calcification (AAC) in a Chinese population.

METHODS

Quantitative computed tomography (QCT) and Agatston score (AS) were used to measure vBMD and AAC, respectively, in 3457 participants during 2013-2017. The association between vBMD and AAC was assessed using multivariate regression analysis, adjusted for age, residence, education, body mass index, and other cardiovascular risk factors.

RESULTS

The mean age of women and men was 61.4 and 62.7 years, respectively. In total, 30.4% of women and 37.7% of men were found to have AAC. After full adjustment, higher vBMD was associated with lower AAC score (β, -0.095; 95% confidence interval [CI], -0.167 to -0.024; P = 0.0087) and lower AAC prevalence (odds ratio [OR], 0.873; 95% CI, 0.824 to 0.924; P < 0.0001) in men. Inverse trends were also observed in the association of vBMD quartile with AAC severity (lowest vs highest quartile; β = 0.235; 95% CI, 0.011 to 0.459; P_trend < 0.0001) and AAC prevalence (lowest vs highest quartile; OR = 1.329; 95% CI, 1.087 to 1.625; P_trend < 0.0001) in men. However, no significant result was obtained in women, except for the association between quartiles of vBMD and AAC score.

CONCLUSIONS

In our study, vBMD was inversely associated with AAC among men independent of age and shared risk factors. However, the association was not significant among women.

Association between vertebral fractures and coronary artery calcification in current and former smokers in the ECLIPSE cohort

In smokers and former smokers from the ECLIPSE cohort, there is an association between prevalent vertebral fractures (VFs) and coronary artery calcification (CAC). Chest CT scans provide the opportunity to evaluate VFs and CAC, which are potentially important comorbidities, each of which is amenable to effective interventions.

INTRODUCTION

Prevalence of VFs among smokers and patients with chronic obstructive pulmonary disease (COPD) is high, and an association between CAC and osteoporosis has been described. We investigated the associations between VFs and CAC (expressed in Agatston score) in (former) smokers.

METHODS

Current and former smokers from the ECLIPSE study (designed to determine underlying COPD progression mechanisms) were studied. Baseline Agatston score (zero (0), medium (1-400), or high (> 400)), baseline bone attenuation (BA), and prevalent and incident VFs (vertebrae T₁-L₁) were assessed on CT.

RESULTS

A total of 586 subjects were included (mean age 59.8 ± 8.3; 62.3% men; 70.1% with COPD; 21.0% with prevalent VFs; 196 with zero, 266 with medium, and 124 with high Agatston score). Of these, 23.4% suffered incident VFs within 3 years. In multivariate models, prevalent VFs were associated with medium (1.83 [95% CI 1.01-3.30]) and with high (OR = 3.06 [1.45-6.47]) Agatston score. After adjustment for BA, prevalent VFs were still associated with high (OR = 2.47 [1.13-5.40]), but not significantly with medium Agatston score (OR = 1.57 [0.85-2.88]). Similarly, after adjustment for BA, high (OR = 2.06 [1.02-4.13]) but not medium Agatston score (OR = 1.61 [0.88-2.94]) was associated with prevalent VFs. Agatston score at baseline was not associated with short-term VF incidence.

CONCLUSION

In (former) smokers, there was an association between prevalent VFs and Agatston score. Chest CT scans provide the opportunity to also evaluate for VFs and CAC, which are potentially important comorbidities, each of which is amenable to effective interventions.

Abdominal aortic calcification (AAC) and ankle-brachial index (ABI) predict health care costs and utilization in older men, independent of prevalent clinical cardiovascular disease and each other

BACKGROUND AND AIMS

Abdominal aortic calcification (AAC) and low ankle-brachial index (ABI) are markers of multisite atherosclerosis. We sought to estimate their associations in older men with health care costs and utilization adjusted for each other, and after accounting for CVD risk factors and prevalent CVD diagnoses.

METHODS

This was an observational cohort study of 2393 community-dwelling men (mean age 73.6 years) enrolled in the Osteoporotic Fractures in Men (MrOS) study and U.S. Medicare Fee for Service (FFS). AAC was scored on baseline lateral lumbar spine X-rays using a 24-point scale. ABI was measured as the lowest ratio of arm to right or left ankle blood pressure. Health care costs, hospital stays, and SNF stays were identified from Medicare FFS claims over 36 months following the baseline visit.

RESULTS

Men with AAC score ≥9 (n = 519 [21.7% of analytic cohort]) had higher annualized total health care costs of $1473 (95% C.I. 293, 2654, 2017 U S. dollars) compared to those with AAC score 0-1, after multivariable adjustment. Men with ABI <0.90 (n = 154 [6.4% of analytic cohort]) had higher annualized total health care costs of $2705 (95% CI 634, 4776) compared to men with normal ABI (≥0.9 and < 1.4), after multivariable adjustment.

CONCLUSIONS

High levels of AAC and low ABI in older men are associated with higher subsequent health care costs, after accounting for clinical CVD risk factors, prevalent CVD diagnoses, and each other. Further investigations of whether preventing progression of peripheral vascular disease and calcification reduces subsequent health care costs are warranted.

Decreased bone mineral density and osteoporotic fractures are associated with the development of echogenic plaques in the carotid arteries over a 10-year follow-up period: The Japanese Population-based Osteoporosis (JPOS) Cohort Study

OBJECTIVES

To investigate whether low bone mineral density (BMD) and history of fracture at baseline are associated with the development of echogenic carotid plaques over a 10-year follow-up period.

STUDY DESIGN

A prospective cohort study.

MAIN OUTCOME MEASURES

Development of echogenic plaques identified by ultrasonography of the carotid arteries.

METHODS

Among 1048 women aged 40 or more who completed the baseline survey of the Japanese Population-based Osteoporosis (JPOS) cohort study, 500 women who completed the first decade of follow-up and 267 women who completed the second decade of follow-up were included. We identified history and incidence of clinical osteoporotic fracture during the follow-up through medical interviews, and determined vertebral fractures by morphometry of absorptiometric images.

RESULTS

We identified 67 (13.4%) and 31 (11.6%) women with echogenic plaques at the end of first and second decade of follow-up, respectively. Participants with echogenic plaques were significantly older, exhibited lower spine BMD, and had a higher prevalence of osteoporotic fracture, diabetes, and hypertension. A generalized estimating equation analysis was used to combine the participants from the two follow-up periods into a single cohort, and showed that osteoporotic BMD and osteoporotic fractures were significantly associated with the development of echogenic plaques, after adjusting for atherosclerosis risk factors (odds ratio (OR): 2.15, 95% confidence interval (95% CI): 1.04, 4.44; OR: 1.84, 95% CI: 1.03, 3.28, respectively).

CONCLUSION

Osteoporotic BMD and osteoporotic fracture history were significantly, and independently, associated with an increased occurrence of echogenic plaques. Ultrasonographic screening of the carotid artery may benefit patients with osteoporosis.

The association between CD31hiEmcnhi endothelial cells and bone mineral density in Chinese women

Osteoporosis is the most common bone disease in humans. During bone remodeling, specialized blood vessels influenced by the endothelial cells (CD31^hiEmcn^hi, also called type H cells) are formatted to supply nutrients. Reductions in vascular supply are associated with bone loss resulting in osteoporosis. Therefore, the objective of the present study was to explore the association between the CD31^hiEmcn^hi endothelial cells and bone mineral density (BMD). In this prospective study, 134 Chinese women were enrolled and examined. BMD was measured by DEXA method while the percentage of CD31^hiEmcn^hi endothelial cells in the intertrochanteric part was measured by flow cytometry. The percentage of CD31^hiEmcn^hi endothelial cells in postmenopausal subjects was significantly lower compared with premenopausal women (8.7 ± 4.0% vs 13.2 ± 5.6%, P < 0.01). Meanwhile, the CD31^hiEmcn^hi endothelial cell levels in osteopenia and osteoporosis were significantly lower compared with subjects with normal BMD (9.84 ± 4.2% in osteopenia and 7.11 ± 3.2% in osteoporosis vs 12.7 ± 5.6% in subjects with normal T score, P < 0.01). Multiple regression analyses showed that the CD31^hiEmcn^hi endothelial cells level was positively associated with femur neck and total hip BMD, but not with lumbar BMD. Our study suggests a significantly positive association between CD31^hiEmcn^hi endothelial cells and local BMD in Chinese women. The proportion of CD31^hiEmcn^hi endothelial cells is a marker of bone quality and represents a potential target for treatment of bone loss.

Abdominal aortic calcification, bone mineral density and fractures: a systematic review and meta-analysis protocol

INTRODUCTION

Abdominal aortic calcification (AAC) is associated with low bone mass and increased fracture risk. Two previous meta-analyses have investigated the association between AAC and fracture. However, these meta-analyses only identified articles until December 2016, undertook limited searches and did not explore potential sources of between-study heterogeneity. We aim to undertake a sensitive and comprehensive assessment of the relationship between AAC, bone mineral density (BMD) as well as prevalent and incident fractures.

METHODS

We will search MEDLINE, EMBASE, Web of Science core collection and Google Scholar (top 200 articles sorted by relevance) from their inception to 1 June 2018. Reference lists of included studies and previous systematic reviews will be hand searched for additional eligible studies. Retrospective and prospective cohort studies (cross-sectional, case-control and longitudinal) reporting the association between AAC, BMD and fracture at any site will be included. At least two investigators will independently: (A) evaluate study eligibility and extract data, with a third investigator to adjudicate when discrepancies occur, (B) assess study quality by the Newcastle-Ottawa Scale for each cohort/study. The meta-analysis will be reported in adherence to the Meta-analysis of Observational Studies in Epidemiology criteria. AAC will be grouped as either: (1) AAC present or absent, (2) AAC categorised as 'low' (referent-lowest reported group) versus 'high' (all other groups) or (3) dose-response when AAC was assessed in ≥3 groups. Where primary event data were reported in individual studies, pooled risk differences and risk ratios with 95% CI will be calculated, from which, a summary estimate will be determined using DerSimonian-Laird random effects models. For the AAC and BMD pooled analyses, estimates will be expressed as standardised mean difference with 95% CI. We will examine the likelihood of publication bias and where possible, investigate potential reasons for between-study heterogeneity using subgroup analyses and meta-regression.

ETHICS AND DISSEMINATION

The study will be submitted to a peer- reviewed journal and disseminated via research presentations.

PROSPERO REGISTRATION NUMBER

CRD42018088019.

Clinical advantages and disadvantages of anabolic bone therapies targeting the WNT pathway

The WNT signalling pathway is a key regulator of bone metabolism, particularly bone formation, which has helped to define the role of osteocytes - the most abundant bone cells - as orchestrators of bone remodelling. Several molecules involved in the control of the WNT signalling pathway have been identified as potential targets for the development of bone-building therapeutics for patients with osteoporosis. Several of these molecules have been investigated in animal models, but only inhibitors of sclerostin (which is produced by osteocytes) have been investigated in phase III clinical studies. Here, we review the rationale for these developments and the specificity and potential off-target actions of WNT-based therapeutics. We also describe the available preclinical and clinical studies and discuss the benefits and risks of using sclerostin inhibitors for the management of patients with osteoporosis.

Diabetes and Abdominal Aortic Calcification-a Systematic Review

PURPOSE OF REVIEW

A systematic literature review was performed to evaluate diabetes mellitus (DM) as a risk factor of abdominal aortic calcification (AAC), and address factors that might contribute to the development of AAC in DM patients.

RECENT FINDINGS

DM is an independent risk factor of AAC development. Bone metabolism along with lifestyle factors among DM patients makes them more prone to AAC. Hip and vertebral fractures, high phosphate, smoking, hypertension, and low osteocalcin could make DM patients prone to AAC. Low levels of high-density lipoprotein (HDL), high low-density lipoprotein (LDL), high total cholesterol/HDL ratio, low bone mineral density (BMD) may be risk factors, but the literature is more ambiguous. Body mass index (BMI) does not appear to increase risk of AAC. High phosphate levels and low osteocalcin levels seem to be biomarkers of AAC in patients with diabetes. However, the association between DM and AAC is complicated.