Osteoporosis and atherosclerosis: a post-mortem MDCT study of an elderly cohort

The Vessels-Bone Axis: Iliac Artery Calcifications, Vertebral Fractures and Vitamin K from VIKI Study

Vascular calcification and fragility fractures are associated with high morbidity and mortality, especially in end-stage renal disease. We evaluated the relationship of iliac arteries calcifications (IACs) and abdominal aortic calcifications (AACs) with the risk for vertebral fractures (VFs) in hemodialysis patients. The VIKI study was a multicenter cross-sectional study involving 387 hemodialysis patients. The biochemical data included bone health markers, such as vitamin K levels, vitamin K-dependent proteins, vitamin 25(OH)D, alkaline phosphatase, parathormone, calcium, and phosphate. VF, IACs and AACs was determined through standardized spine radiograms. VF was defined as >20% reduction of vertebral body height, and VC were quantified by measuring the length of calcium deposits along the arteries. The prevalence of IACs and AACs were 56.1% and 80.6%, respectively. After adjusting for confounding variables, the presence of IACs was associated with 73% higher odds of VF (p = 0.028), whereas we found no association (p = 0.294) for AACs. IACs were associated with VF irrespective of calcification severity. Patients with IACs had lower levels of vitamin K2 and menaquinone 7 (0.99 vs. 1.15 ng/mL; p = 0.003), and this deficiency became greater with adjustment for triglycerides (0.57 vs. 0.87 ng/mL; p < 0.001). IACs, regardless of their extent, are a clinically relevant risk factor for VFs. The association is enhanced by adjusting for vitamin K, a main player in bone and vascular health. To our knowledge these results are the first in the literature. Prospective studies are needed to confirm these findings both in chronic kidney disease and in the general population.

Abdominal aortic calcification is associated with decline in handgrip strength in the U.S. adult population ≥40 years of age

BACKGROUND AND AIMS

The present study investigated the association between abdominal aortic calcification (AAC) and handgrip strength (HGS) and the ability of HGS to predict an increased AAC phenotype in adults.

METHODS AND RESULTS

The analysis consisted of data for 3140 men and women aged ≥40 years (51.7% women) from the 2013-2014 NHANES. Lateral scans of the thoraco-lumbar spine (L1-L4) were scored for AAC using a validated 8-point scale (AAC-8); subjects with a score of ≥3 were considered at increased risk for cardiovascular disease due to a high AAC phenotype. HGS was assessed using a grip dynamometer. The prevalence of severe AAC in the population was 9.0%. Decline in HGS was associated with higher AAC-8 scores in men and women (p < 0.001). General linear model analysis showed that HGS levels were negatively associated with high AAC (p < 0.001) and AAC-8 status for both sexes. Likewise, for each 5-kg higher HGS, there lower odds of a high AAC phenotype (in men OR = 0.73, CI95%, 0.64-0.84) and (women OR = 0.58, CI95%, 0.47-0.70). Receiver operating characteristic curve analysis showed that the HGS threshold value to detect high risk of AAC in adults was ≥37.3 kg (AUC = 0.692) in men and 25.1 kg (AUC = 0.705) in women.

CONCLUSION

Lower muscular strength, as measured by HGS, is associated with higher AAC scores in the U.S. population ≥40 years of age. Accordingly, maintenance of muscular strength during aging may protect adults against vascular calcification, an independent predictor of cardiovascular events. HGS measurement seems to be a valid screening tool for detecting a high ACC phenotype in adults.

Osteoporosis: what the clinician needs to know?

Osteoporosis is a common condition and an important cause of disability. For this reason, early detection of the disease and patients at higher risk of bone fractures is compulsory. In the recent years, conventional quantitative methods have been spreading for the diagnosis of osteoporosis; moreover, new improvements in computed tomography (CT) and magnetic resonance imaging (MRI) have been made in this field and imaging findings may correlate to the morphological and structural changes within the bone.

Decreased Bone Mineral Density Is an Independent Predictor for the Development of Atherosclerosis: A Systematic Review and Meta-Analysis

Background

There is conflicting evidence regarding the association between decreased bone mineral density (BMD) and atherosclerosis. To this end, we performed a systematic review and meta-analysis to clarify the association.

Methods

To identify relevant studies, PubMed, Embase, and the Cochrane Library were systematically searched up to November 2015. All observational and comparative studies directly investigating the relationship between decreased BMD and clinical consequences of atherosclerotic vascular abnormalities, including carotid artery calcification (CAC), cardiovascular disease (CAD), and coronary artery disease (CAD) were obtained, without limitation of language or publication year.

Results

A total of 25 studies involving 10,299 patients were included. The incidence of atherosclerotic vascular abnormalities was significantly increased in low BMD patients, compared to patients with normal BMD (OR, 1.81, 95% CI [1.01, 2.19], p<0.00001)). Similar results were also observed for postmenopausal women (OR, 2.23, 95% CI [1.72, 2.89], p<0.00001). Subgroup analyses of osteopenia, osteoporosis, and normal BMD also revealed that the combined ORs for the incidence of atherosclerotic vascular abnormalities increased as BMD decreased. Of note, after adjusting for age, sex, body mass index (BMI) and other vascular risk factors, decreased BMD remained significantly associated with the incidence of atherosclerotic vascular abnormalities (OR, 2.96, 95% CI [2.25, 3.88], p < 0.00001).

Conclusions

Based on the results of this study, decreased BMD is an independent predictor for the development of atherosclerosis in elderly individuals. Moreover, the risk of atherosclerotic vascular abnormalities increased as BMD decreased. Future studies focusing on individuals with different severities of atherosclerosis and comorbidities are of interest.

Inter-observer and inter-examination variability of manual vertebral bone attenuation measurements on computed tomography

Objective

To determine inter-observer and inter-examination variability of manual attenuation measurements of the vertebrae in low-dose unenhanced chest computed tomography (CT).

Methods

Three hundred and sixty-seven lung cancer screening trial participants who underwent baseline and repeat unenhanced low-dose CT after 3 months because of an indeterminate lung nodule were included. The CT attenuation value of the first lumbar vertebrae (L1) was measured in all CTs by one observer to obtain inter-examination reliability. Six observers performed measurements in 100 randomly selected CTs to determine agreement with limits of agreement and Bland-Altman plots and reliability with intraclass correlation coefficients (ICCs). Reclassification analyses were performed using a threshold of 110 HU to define osteoporosis.

Results

Inter-examination reliability was excellent with an ICC of 0.92 (p < 0.001). Inter-examination limits of agreement ranged from -26 to 28 HU with a mean difference of 1 ± 14 HU. Inter-observer reliability ICCs ranged from 0.70 to 0.91. Inter-examination variability led to 11.2 % reclassification of participants and inter-observer variability led to 22.1 % reclassification.

Conclusions

Vertebral attenuation values can be manually quantified with good to excellent inter-examination and inter-observer reliability on unenhanced low-dose chest CT. This information is valuable for early detection of osteoporosis on low-dose chest CT.

Key Points

• Vertebral attenuation values can be manually quantified on low-dose unenhanced CT reliably.

• Vertebral attenuation measurements may be helpful in detecting subclinical low bone density.

• This could become of importance in the detection of osteoporosis.

Electronic supplementary material

The online version of this article (doi:10.1007/s00330-015-4145-x) contains supplementary material, which is available to authorized users.