Lower leg arterial calcification assessed by high-resolution peripheral quantitative computed tomography is associated with bone microstructure abnormalities in women

Vascular deficits contributing to skeletal fragility in type 1 diabetes

Over 1 million Americans are currently living with T1D and improvements in diabetes management have increased the number of adults with T1D living into later decades of life. This growing population of older adults with diabetes is more susceptible to aging comorbidities, including both vascular disease and osteoporosis. Indeed, adults with T1D have a 2- to 3- fold higher risk of any fracture and up to 7-fold higher risk of hip fracture compared to those without diabetes. Recently, diabetes-related vascular deficits have emerged as potential risks factors for impaired bone blood flow and poor bone health and it has been hypothesized that there is a direct pathophysiologic link between vascular disease and skeletal outcomes in T1D. Indeed, microvascular disease (MVD), one of the most serious consequences of diabetes, has been linked to worse bone microarchitecture in older adults with T1D compared to their counterparts without MVD. The association between the presence of microvascular complications and compromised bone microarchitecture indicates the potential direct deleterious effect of vascular compromise, leading to abnormal skeletal blood flow, altered bone remodeling, and deficits in bone structure. In addition, vascular diabetic complications are characterized by increased vascular calcification, decreased arterial distensibility, and vascular remodeling with increased arterial stiffness and thickness of the vessel walls. These extensive alterations in vascular structure lead to impaired myogenic control and reduced nitric-oxide mediated vasodilation, compromising regulation of blood flow across almost all vascular beds and significantly restricting skeletal muscle blood flow seen in those with T1D. Vascular deficits in T1D may very well extend to bone, compromising skeletal blood flow control, and resulting in reduced blood flow to bone, thus negatively impacting bone health. Indeed, several animal and ex vivo human studies report that diabetes induces microvascular damage within bone are strongly correlated with diabetes disease severity and duration. In this review article, we will discuss the contribution of diabetes-induced vascular deficits to bone density, bone microarchitecture, and bone blood flow regulation, and review the potential contribution of vascular disease to skeletal fragility in T1D.

High-resolution peripheral quantitative computed tomography: research or clinical practice?

High-resolution peripheral quantitative CT (HR-pQCT) is a low-dose three-dimensional imaging technique, originally developed for in vivo assessment of bone microarchitecture at the distal radius and tibia in osteoporosis. HR-pQCT has the ability to discriminate trabecular and cortical bone compartments, providing densitometric and structural parameters. At present, HR-pQCT is mostly used in research settings, despite evidence showing that it may be a valuable tool in osteoporosis and other diseases. This review summarizes the main applications of HR-pQCT and addresses the limitations that currently prevent its integration into routine clinical practice. In particular, the focus is on the use of HR-pQCT in primary and secondary osteoporosis, chronic kidney disease (CKD), endocrine disorders affecting bone, and rare diseases. A section on novel potential applications of HR-pQCT is also present, including assessment of rheumatic diseases, knee osteoarthritis, distal radius/scaphoid fractures, vascular calcifications, effect of medications, and skeletal muscle. The reviewed literature seems to suggest that a more widespread implementation of HR-pQCT in clinical practice would offer notable opportunities. For instance, HR-pQCT can improve the prediction of incident fractures beyond areal bone mineral density provided by dual-energy X-ray absorptiometry. In addition, HR-pQCT may be used for the monitoring of anti-osteoporotic therapy or for the assessment of mineral and bone disorder associated with CKD. Nevertheless, several obstacles currently prevent a broader use of HR-pQCT and would need to be targeted, such as the small number of installed machines worldwide, the uncertain cost-effectiveness, the need for improved reproducibility, and the limited availability of reference normative data sets.

4 days in dry immersion increases arterial wall response to ultrasound wave as measured using radio-frequency signal, comparison with spaceflight data

Recent studies have reported a significant increase in common carotid artery (CCA) intima media thickness, wall stiffness and reflectivity to ultrasound, in astronauts, after six months of spaceflight. The hypothesis was that 4 days in dry immersion (subjects under bags of water) will be sufficient to change the CCA wall reflectivity to ultrasound similar to what observed after spaceflight. Such response would be quantified using the amplitude of the ultrasound signal returned to the probe by the target concerned. [coefficient of signal return (Rs)]. The Rs for anterior and posterior CCA wall, sternocleidomastoid muscle, intima layer and CCA lumen were calculated from the ultrasound radio frequency (RF) data displayed along each echographic line. After four days of DI, Rs increased in the CCA posterior wall (+15% +/- 10 from pre DI, p < 0.05), while no significant change was observed in the other targets. The observed increase in Rs with DI was approximately half compared to what was observed after six months of space flight (+34% +/- 14). This difference may be explained by dose response (dry immersion only four days in duration). As a marker of tissue-level physical changes, Rs provide complimentary information alongside previously observed CCA wall thickness and stiffness.

Association of Abdominal Aortic Calcification with Peripheral Quantitative Computed Tomography Bone Measures in Older Women: The Perth Longitudinal Study of Ageing Women

We have previously shown that abdominal aortic calcification (AAC), a marker of advanced atherosclerotic disease, is weakly associated with reduced hip areal bone mineral density (aBMD). To better understand the vascular-bone health relationship, we explored this association with other key determinants of whole-bone strength and fracture risk at peripheral skeletal sites. This study examined associations of AAC with peripheral quantitative computed tomography (pQCT)-assessed total, cortical and trabecular volumetric BMD (vBMD), bone structure and strength of the radius and tibia among 648 community-dwelling older women (mean ± SD age 79.7 ± 2.5 years). We assessed associations between cross-sectional (2003) and longitudinal (progression from 1998/1999-2003) AAC assessed on lateral dual-energy X-ray absorptiometry (DXA) images with cross-sectional (2003) and longitudinal (change from 2003 to 2005) pQCT bone measures at the 4% radius and tibia, and 15% radius. Partial Spearman correlations (adjusted for age, BMI, calcium treatment) revealed no cross-sectional associations between AAC and any pQCT bone measures. AAC progression was not associated with any bone measure after adjusting for multiple comparisons, despite trends for inverse correlations with total bone area at the 4% radius (r_s =  - 0.088, p = 0.044), 4% tibia (r_s =  - 0.085, p = 0.052) and 15% radius (r_s =  - 0.101, p = 0.059). Neither AAC in 2003 nor AAC progression were associated with subsequent 2-year pQCT bone changes. ANCOVA showed no differences in bone measures between women with and without AAC or AAC progression, nor across categories of AAC extent. Collectively, these finding suggest that peripheral bone density and structure, or its changes with age, are not associated with central vascular calcification in older women.

Why Aboriginal and Torres Strait Islander Australians fall and fracture: the codesigned Study of Indigenous Muscle and Bone Ageing (SIMBA) protocol

OBJECTIVES

Aboriginal and Torres Strait Islander Australians have a substantially greater fracture risk, where men are 50% and women are 26% more likely to experience a hip fracture compared with non-Indigenous Australians. Fall-related injuries in this population have also increased by 10%/year compared with 4.3%/year in non-Indigenous Australians. This study aims to determine why falls and fracture risk are higher in Aboriginal and Torres Strait Islander Australians.

SETTING

All clinical assessments will be performed at one centre in Melbourne, Australia. At baseline, participants will have clinical assessments, including questionnaires, anthropometry, bone structure, body composition and physical performance tests. These assessments will be repeated at follow-up 1 and follow-up 2, with an interval of 12 months between each clinical visit.

PARTICIPANTS

This codesigned prospective observational study aims to recruit a total of 298 adults who identify as Aboriginal and Torres Strait Islander and reside within Victoria, Australia. Stratified sampling by age and sex will be used to ensure equitable distribution of men and women across four age-bands (35-44, 45-54, 55-64 and 65+ years).

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome is within-individual yearly change in areal bone mineral density at the total hip, femoral neck and lumbar spine assessed by dual energy X-ray absorptiometry. Within-individual change in cortical and trabecular volumetric bone mineral density at the radius and tibia using high-resolution peripheral quantitative computed tomography will be determined. Secondary outcomes include yearly differences in physical performance and body composition.

ETHICAL APPROVAL

Ethics approval for this study has been granted by the Monash Health Human Research Ethics Committee (project number: RES-19-0000374A).

TRIAL REGISTRATION NUMBER

ACTRN12620000161921.

Index of Reflectivity of Ultrasound Radio Frequency Signal from the Carotid Artery Wall Increases in Astronauts after a 6 mo Spaceflight

The objective was to quantify the index of reflectivity of the common carotid artery and surrounding structures, before and after 6 mo of microgravity. Our hypothesis was that structural changes in the insonated target would increase its index of reflectivity. The neck anterior muscle and common carotid artery (walls and lumen) were visualized by echography (17 MHz linear probe), and the radiofrequency signal along each vertical line was displayed. The limits of the radiofrequency data corresponding to each target (muscle, vessel wall) were determined from the B-mode image and radiofrequency trace. Each target's index of reflectivity was calculated as the proportion of backscattered energy to the whole backscattered energy along the line. After 6 mo in flight, the index of reflectivity increased significantly for both common carotid walls, while it remained unchanged for the neck muscle, carotid intima and lumen. The index of reflectivity provided additional information beyond traditional B-mode imaging.

Lower Leg Arterial Calcifications Assessed by High-Resolution Peripheral Quantitative Computed Tomography in Hypoparathyroid and Pseudohypoparathyroid Patients

Hypoparathyroidism (HypoPT) and pseudohypoparathyroidism (PHP) are diseases with abnormal calcium and phosphate homeostasis and low and high PTH levels, respectively. It has been hypothesized that this could dispose to vascular calcifications and thereby perhaps also cardiovascular morbidity. The aim of this study was to assess lower leg arterial calcifications (LLAC) in patients with HypoPT or PHP. Using a cross-sectional design, we measured the LLAC using a high-resolution peripheral quantitative computed tomography (HR-pQCT) scanner in 72 patients with HypoPT and 25 patients with PHP and compared them with findings in 61 controls. LLAC were found in only two (3%) of the controls. Compared to the controls, LLAC were significantly more prevalent in patients with HypoPT (N = 12, [17%], p < 0.01) and PHP (N = 4, [16%], p < 0.04). Compared to the patients without calcifications, patients with calcifications had higher plasma calcium levels and a lower eGFR, as well as they were older and more often males. Plasma phosphate levels and the calcium-phosphate product were not associated with LLAC. In conclusion, we found that HypoPT and PHP are associated with an increased prevalence of vascular calcifications.

High Cardiovascular Risk in Older Men With Severe Peripheral Artery Calcification on High-Resolution Peripheral QCT Scans: The STRAMBO Study

[Figure: see text].

Vascular calcification relationship to vascular biomarkers and bone metabolism in advanced chronic kidney disease

BACKGROUND

Vascular calcification (VC) and renal osteodystrophy are important complications of advanced chronic kidney disease (CKD). High resolution peripheral quantitative computed tomography (HRpQCT) is able to assess bone microstructure in renal osteodystrophy and lower leg arterial calcification (LLAC) is usually seen as an incidental finding. LLAC can be a useful quantitative assessment of VC in CKD but the relationship between LLAC and vascular biomarkers and bone is unknown. We aimed to assess the relationship between LLAC and biomarkers, bone turnover and microstructure.

METHODS

In this cross-sectional study, fasting blood samples were taken from 69 CKD stages 4-5D patients and 68 healthy controls. HRpQCT of distal tibia and radius were performed. 43 CKD patients had trans-iliac bone biopsy after tetracycline labelling.

RESULTS

LLAC was more severe in CKD than controls (median [IQR] 1.043 [0.05-16.52] vs 0 [0-0.55] mgHA, p < 0.001). CKD patients with diabetes (28%) had significantly higher LLAC compared to non-diabetic CKD (median [IQR] 24.07 [3.42-61.30] vs 0.23 [0-3.78] mgHA, p < 0.001). LLAC mass in CKD correlated with serum phosphate (rho = 0.29, p < 0.05), calcium x phosphate product (rho = 0.31, p < 0.05), intact parathyroid hormone (rho = 0.38, p < 0.01), intact fibroblast growth factor-23 (iFGF23) (rho = 0.40, p = 0.001), total alkaline phosphatase (rho = 0.41, p < 0.001), bone alkaline phosphatase (rho = 0.29, p < 0.05), osteocalcin (rho = 0.32, p < 0.05), osteoprotegerin (rho = 0.40, p = 0.001) and dephosphorylated-uncarboxylated matrix Gla protein (rho = 0.31, p < 0.05). LLAC in CKD also correlated with worse distal tibia cortical bone mineral density, thickness and porosity. No association was found between LLAC and bone turnover, mineralization or volume on biopsy in CKD. In multivariate analysis, only age, diabetes, iPTH and iFGF23 were independently associated with LLAC in CKD.

CONCLUSIONS

High levels of PTH and FGF23, along with older age and the presence of diabetes may all play independent roles in the development of LLAC in advanced CKD.

Sex-Specific Associations Between Cardiac Workload, Peripheral Vascular Calcification, and Bone Mineral Density: The Gambian Bone and Muscle Aging Study

Noncommunicable diseases (NCD) are rapidly rising in Africa, with multimorbidity increasing the burden on health and social care. Osteoporosis and cardiovascular disease (CVD) share common risk factors; both often remain undiagnosed until a major life-threatening event occurs. We investigated the associations between cardiac workload, peripheral vascular calcification (PVC), and bone parameters in Gambian adults. The Gambian Bone and Muscle Aging Study (GamBAS) recruited 249 women and 239 men aged 40 to 75+ years. Body composition and areal bone mineral density (aBMD) were measured using dual-energy X-ray absorptiometry; peripheral quantitative computed tomography (pQCT) scans were performed at the radius and tibia. Supine blood pressure and heart rate were measured and used to calculate rate pressure product and pulse pressure. Presence of PVC was determined from tibia pQCT scans. Sex interactions were tested (denoted as p-int); adjustments were made for residuals of appendicular lean mass (ALM) and fat mass (FM). There were negative associations between rate pressure product and aBMD in women only, all p-int < .05; after adjustment for ALM residuals, for every 10% increase in rate pressure product, aBMD was lower at the whole body (-0.6% [-1.2, -0.1]), femoral neck (-0.9% [-1.8, -0.05]), L1 to L4 (-0.6% [-1.7, 0.5]), and radius (-1.9% [-2.8, -0.9]); there were similar associations when adjusted for FM residuals. Similar negative associations were found between pulse pressure and aBMD in women only. PVC were found in 26.6% men and 22.5% women; women but not men with calcification had poorer cardiac health and negative associations with aBMD (all sites p-int < .001). There were consistent associations with cardiac parameters and pQCT outcomes at the radius and tibia in women only. Multiple markers of cardiac health are associated with poorer bone health in Gambian women. In the context of epidemiological transition and changing NCD burden, there is a need to identify preventative strategies to slow/prevent the rising burden in CVD and osteoporosis in Sub-Saharan Africa. © 2020 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Effect of high-dose vitamin D supplementation on peripheral arterial calcification: secondary analysis of a randomized controlled trial

Although high-dose vitamin D supplementation is common, effects on arterial calcification remain unexplored. Tibial artery calcification was identified and quantified over 3 years in participants randomized to 400, 4000, or 10,000 IU vitamin D₃ daily. High-dose vitamin D supplementation did not affect the development or progression of arterial calcification.

INTRODUCTION

To determine whether vitamin D supplementation has a dose-dependent effect on development and progression of arterial calcification.

METHODS

This was a secondary analysis of the Calgary Vitamin D Study, a 3-year, double-blind, randomized controlled trial conducted at a single-center in Calgary, Canada. Participants were community-dwelling adults aged 55-70 years with serum 25-hydroxyvitamin D 30-125 nmol/L. Participants were randomized 1:1:1 to receive vitamin D₃ 400, 4000, or 10,000 IU/day for 3 years. Tibial artery calcification was identified and quantified (in milligrams of hydroxyapatite, mgHA) using high-resolution peripheral quantitative computed tomography (HR-pQCT) at baseline and 6, 12, 24, and 36 months. Changes in calcification over time and treatment group interaction were evaluated using a constrained linear mixed effects model.

RESULTS

Of 311 randomized participants, 302 (400: 105, 4000: 96, 10,000: 101) were eligible for analysis of arterial calcification (54% male, mean (SD) age 62 (4) years, mean (SD) 25-hydroxyvitamin D 78.9 (19.9) nmol/L). At baseline, 85 (28%) had tibial artery calcification, and mean (95% CI) calcification quantity was 2.8 mgHA (95% CI 1.7-3.9). In these 85 participants, calcification quantity increased linearly by 0.020 mgHA/month (95% CI 0.012-0.029) throughout the study, with no evidence of a treatment-group effect (p = 0.645 for interaction). No participants developed new arterial calcifications during the study.

CONCLUSIONS

In this population of community-dwelling adults who were vitamin D replete at baseline, supplementation with vitamin D 400, 4000, or 10,000 IU/day did not have differential effects on the development or progression of arterial calcification over 3 years.

TRIAL REGISTRATION

clinicaltrials.gov (NCT01900860).

No Association Between Bone Mineral Density and Breast Arterial Calcification Among Postmenopausal Women

Context

The association between bone mineral density (BMD) and breast arterial calcification (BAC) remains poorly understood and controversial.

Objective

The objective of this article is to examine the association between BMD and BAC in a large cohort of postmenopausal women undergoing routine mammography.

Design

A cross-sectional analysis of baseline data from a multiethnic cohort was performed.

Setting

The setting for this analysis is an integrated health care delivery system in Northern California in the United States.

Patients

A total of 1273 women age 60 to 79 years (mean age, 67 years) were recruited within 12 months of screening mammography.

Main outcome measure

A BAC score (mg) was obtained from digital mammograms using a novel densitometry method. BAC presence was defined as a BAC score greater than 0 mg, and severe BAC as a BAC score greater than 20 mg.

Results

Overall, 53% of women had osteopenia and 21% had osteoporosis. The prevalence of BAC greater than 0 mg was 29%, 30%, and 29% among women with normal BMD, osteopenia, and osteoporosis, respectively (P = 0.98). The prevalence of BAC greater than 20 mg was 5%, 3%, and 5% among women with normal BMD, osteopenia and osteoporosis, respectively (P = .65). The odds ratios (ORs) of BAC greater than 0 mg vs BAC = 0 mg after multivariable adjustment were 1.09 (95% CI, 0.81-1.48; P = .54) for osteopenia and 0.99 (95% CI, 0.69-1.48; P = .98) for osteoporosis. The adjusted ORs for BAC greater than 20 mg vs BAC 20 mg or less were 1.03 (95% CI, 0.52-2.01; P = .93) for osteopenia and 1.89 (95 CI, 0.81-4.47; P = .14) for osteoporosis.

Conclusion

Our findings do not support an association of either osteopenia or osteoporosis with BAC presence or severity among postmenopausal women.

The Hertfordshire Cohort Study: an overview

The Hertfordshire Cohort Study is a nationally unique study of men and women born in the English county of Hertfordshire in the early part of the 20 ^th century. Records that detail their health in infancy and childhood have been preserved, their sociodemographic, lifestyle, medical and biological attributes have been characterised in later life, and routinely collected data on their hospital use and mortality have been acquired. This paper provides an overview of the study since its inception in the 1980s, including its methods, findings, and plans for its future.

Musculoskeletal health of Indigenous Australians

INTRODUCTION

Research on non-communicable diseases (NCD) in Indigenous Australians has mostly focused on diabetes mellitus and chronic kidney or cardiovascular disease. Osteoporosis, characterised by low bone mass and structural deterioration of bone tissue, and sarcopenia, the age-related loss of muscle mass and strength, often co-exist with these common NCDs-the combination of which will disproportionately increase bone fragility and fracture risk and negatively influence cortical and trabecular bone. Furthermore, the social gradient of NCDs, including osteoporosis and fracture, is well-documented, meaning that specific population groups are likely to be at greater risk of poorer health outcomes: Indigenous Australians are one such group.

PURPOSE

This review summarises the findings reported in the literature regarding the muscle and bone health of Indigenous Australians.

FINDINGS

There are limited data regarding the musculoskeletal health of Indigenous Australians; however, areal bone mineral density (aBMD) measured by dual-energy X-ray absorptiometry (DXA) is reported to be greater at the hip compared to non-Indigenous Australians. Falls are the leading cause of injury-related hospitalisations in older Australians, particularly Indigenous Australians, with a great proportion suffering from fall-related fractures. Despite sparse data, it appears that Indigenous men and women have a substantially higher risk of hip fracture at a much younger age compared to non-Indigenous Australians.

CONCLUSION

Data on more detailed musculoskeletal health outcomes are required in Indigenous Australians to better understand fracture risk and to formulate evidence-based strategies for fracture prevention and to minimise the risk of falls.

Bone mineral density and microarchitecture linkages with micro- and macro-vascular impairments at the hand in systemic sclerosis: an HRpQCT study

Objective

To investigate the link between bone alteration and micro- and macro-vascular disease in patients with systemic sclerosis (SSc).

Results

33 SSc patients were included. In univariate analysis, low values of cortical vBMD were significantly associated with a low DBI at the 2nd finger (p = 0.004) and at the 4th (p = 0.002) and with severe capillaroscopic score (p = 0.008). In multivariate analyses, low cortical vBMD was associated with a low DBI at the 4th finger, age and severe capillaroscopic score (adjusted R² = 0.58; p = < 0.001). Low cortical thickness was associated with a low DBI at the 4th finger, severe capillaroscopic score and age (adjusted R² = 0.49, p = < 0.001).

Conclusion

Our study findings showed an association between micro- and macro-vessel damage and altered microarchitectural indices at the radius in SSc.

Methods

We performed a pilot study in female patients with SSc. Microvascular disease was assessed by the capillaroscopic score of Cutolo. Macrovascular involvement was measured by digito-brachial pressure index (DBI) on laser-Doppler at the 2nd and 4th finger. Volumetric bone mineral density (vBMD) and bone microarchitecture involvement were analysed by High-Resolution peripheral Quantitative Computed Tomography (HRpQCT) at the distal radius.