Low calcidiol levels and risk of progression of aortic calcification

Accelerated Bone Loss in Older Men With Severe Abdominal Aortic Calcification-the Prospective MINOS Study

CONTEXT

Data on the association between the severity of abdominal aortic calcification (AAC) and bone loss are discordant.

OBJECTIVE

Our aim was to assess the association between baseline AAC and prospectively assessed bone loss in older men.

METHODS

This prospective cohort study started in 1995 (MINOS). Men aged 50 to 85 years (n = 778) had AAC assessed on the lateral radiograph of the spine using Kauppila's semiquantitative score and was followed prospectively for 7.5 years. Bone mineral density (BMD) and bone mineral content (BMC) were measured by dual-energy x-ray absorptiometry every 18 months. Statistical analysis was performed using linear mixed models.

RESULTS

In comparison to men without AAC (AAC = 0), severe AAC (>6) was associated with more rapid bone loss at the total hip (-0.62 ± 0.06 vs -0.32 ± 0.04%/year; P < .001), trochanter, and distal forearm (-0.72 ± 0.06 vs -0.45 ± 0.03%/year; P < .001). The highest decile (AAC >10) was associated with more rapid bone loss at the femoral neck, whole body, and ultradistal radius (-0.86 ± 0.12 vs -0.34 ± 0.05%/year; P < .001). The results were similar for BMD and for BMC. The patterns were similar in sensitivity analyses (eg, after excluding men with abdominal obesity, after excluding current smokers, after excluding men with ischemic heart disease or with diabetes mellitus, after excluding men with abnormal concentrations of lipids, bioavailable 17β-estradiol or 25-hydroxycholecalciferol, after excluding men with glomerular filtration rate <60 mL/min).

CONCLUSION

Severe AAC is associated with faster bone loss in older men and may contribute to the higher fracture risk observed in this population.

A single-oral bolus of 100,000 IU of cholecalciferol at hospital admission did not improve outcomes in the COVID-19 disease: the COVID-VIT-D-a randomised multicentre international clinical trial

BACKGROUND

Vitamin D status has been implicated in COVID-19 disease. The objective of the COVID-VIT-D trial was to investigate if an oral bolus of cholecalciferol (100,000 IU) administered at hospital admission influences the outcomes of moderate-severe COVID-19 disease. In the same cohort, the association between baseline serum calcidiol levels with the same outcomes was also analysed.

METHODS

The COVID-VIT-D is a multicentre, international, randomised, open label, clinical trial conducted throughout 1 year. Patients older than 18 years with moderate-severe COVID-19 disease requiring hospitalisation were included. At admission, patients were randomised 1:1 to receive a single oral bolus of cholecalciferol (n=274) or nothing (n=269). Patients were followed from admission to discharge or death. Length of hospitalisation, admission to intensive care unit (ICU) and mortality were assessed.

RESULTS

In the randomised trial, comorbidities, biomarkers, symptoms and drugs used did not differ between groups. Median serum calcidiol in the cholecalciferol and control groups were 17.0 vs. 16.1 ng/mL at admission and 29.0 vs. 16.4 ng/mL at discharge, respectively. The median length of hospitalisation (10.0 [95%CI 9.0-10.5] vs. 9.5 [95%CI 9.0-10.5] days), admission to ICU (17.2% [95%CI 13.0-22.3] vs. 16.4% [95%CI 12.3-21.4]) and death rate (8.0% [95%CI 5.2-12.1] vs. 5.6% [95%CI 3.3-9.2]) did not differ between the cholecalciferol and control group. In the cohort analyses, the highest serum calcidiol category at admission (>25ng/mL) was associated with lower percentage of pulmonary involvement and better outcomes.

CONCLUSIONS

The randomised clinical trial showed the administration of an oral bolus of 100,000 IU of cholecalciferol at hospital admission did not improve the outcomes of the COVID-19 disease. A cohort analysis showed that serum calcidiol at hospital admission was associated with outcomes.

TRIAL REGISTRATION

COVID-VIT-D trial was authorised by the Spanish Agency for Medicines and Health products (AEMPS) and registered in European Union Drug Regulating Authorities Clinical Trials (EudraCT 2020-002274-28) and in ClinicalTrials.gov ( NCT04552951 ).

Clinical Approach to Vascular Calcification in Patients With Non-dialysis Dependent Chronic Kidney Disease: Mineral-Bone Disorder-Related Aspects

Chronic kidney disease (CKD) is associated with a very high morbimortality, mainly from cardiovascular origin, and CKD is currently considered in the high- or very high risk- cardiovascular risk category. CKD-mineral and bone disorders (CKD-MBDs), including vascular and/or valvular calcifications, are also associated with these poor outcomes. Vascular calcification (VC) is very prevalent (both intimal and medial), even in non-dialysis dependent patients, with a greater severity and more rapid progression. Simple X-ray based-scores such as Adragão's (AS) are useful prognostic tools and AS (even AS based on hand-X-ray only) may be superior to the classic Kauppila's score when evaluating non-dialysis CKD patients. Thus, in this mini-review, we briefly review CKD-MBD-related aspects of VC and its complex pathophysiology including the vast array of contributors and inhibitors. Furthermore, although VC is a surrogate marker and is not yet considered a treatment target, we consider that the presence of VC may be relevant in guiding therapeutic interventions, unless all patients are treated with the mindset of reducing the incidence or progression of VC with the currently available armamentarium. Avoiding phosphate loading, restricting calcium-based phosphate binders and high doses of vitamin D, and avoiding normalizing (within the normal limits for the assay) parathyroid hormone levels seem logical approaches. The availability of new drugs and future studies, including patients in early stages of CKD, may lead to significant improvements not only in patient risk stratification but also in attenuating the accelerated progression of VC in CKD.

Rapid Progression of Aortic Calcification in Older Men with Low Appendicular Lean Mass and Poor Physical Function

OBJECTIVES

Assessment of the progression of abdominal aortic calcification (AAC) may be a surrogate marker of the impact of physical function on cardiovascular risk. Our aim was to assess the risk of rapid AAC progression in older men with low relative appendicular lean mass (RALM) and poor physical function.

DESIGN

Prospective cohort study.

SETTING

Community-dwelling older men.

PARTICIPANTS

621 men aged 50-85 followed prospectively (baseline, 3 and 7.5 years).

MEASUREMENTS

Body composition was assessed by DXA. Poor physical function was defined as incapacity to perform ≥1 of 5 clinical tests (balance, muscle strength). AAC was assessed using Kauppila's semiquantitative score. Reclassification improvement was assessed by comparing the areas under the curve (AUC) using DeLong's method.

RESULTS

Rapid AAC progression (>0.6 point/year) was found in 168 men (27.1%). After adjustment for confounders including baseline AAC, the risk of rapid AAC progression increased with lower RALM (OR=1.42/SD, 95%CI: 1.09-1.86, p<0.01) and was higher in the lowest (<7.5kg/m2) vs. highest (>8.6kg/m2) quartile (OR=2.15, 95%CI: 1.17-3.95, p<0.01). Poor physical performance was associated with rapid AAC progression (OR=2.76, 95%CI: 1.48-5.91, p<0.005). Low RALM (<7.84kg/m2 defined using Youden's index) and poor physical function contributed to the risk of rapid AAC progression jointly. Men who had low RALM and poor physical function had higher risk of rapid AAC progression vs. men without these traits (OR=4.66, 95%CI: 1.72-12.62, p<0.05). RALM and physical function improved the identification of men with rapid AAC progression (DAUC=0.026, 95%CI: 0.005-0.046, p<0.05) after adjustment for confounders including baseline AAC score.

CONCLUSIONS

Low RALM and poor physical function are associated with higher risk of rapid AAC progression and possibly represent another measure of cardiovascular risk.

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).

The Effect of Statins on Serum Vitamin D Concentrations Among Older Adults

Background Randomized and observational studies have previously reported inconsistent results for the direct association between statin therapy and 25, hydroxyvitamin D [25(OH)D] levels. Thus, the present study aimed to examine the relationship between statin use and 25(OH)D and its metabolites concentrations in a large nationally representative sample of older adults. Methods This study was conducted using data from the National Health and Nutrition Examination Survey. Participants were asked to show the medication containers of all the products used in the previous 30 days, and the prescription of statins was defined on the three-level nested therapeutic classification scheme of Cerner Multum's Lexicon. General linear models adjusted for potential confounders were created to compare 25(OH)D concentrations between older adults taking statins and those who did not.  Results A total of 6,261 participants with a mean age of 69.5 years comprised the study sample. Of those, 40.2% were taking statins with a median length of therapy of 5 years. Adjusted mean 25(OH)D3 and 25(OH)D levels were 3.3 and 4.4 nmol/L higher among participants taking statins than those who did not, respectively. Moreover, this association was consistently seen regardless of the duration of therapy and particularly in subjects taking simvastatin, atorvastatin, or rosuvastatin. In subgroup analyses according to BMI categories and vitamin D intake, higher 25(OH)D levels were also seen among statin users. By contrast, this association was attenuated among those with a daily vitamin D between 400 and 800 and >800 IU. Conclusion Older adults on statin therapy had significantly higher serum 25(OH)D concentrations. Additional research should be conducted to define the mechanism of this association and determine if the pleiotropic effects attributed to statins may be mediated by vitamin D.

Clinical and subclinical cardiovascular disease in female SLE patients: Interplay between body mass index and bone mineral density

BACKGROUND AND AIMS

Since accelerated atherosclerosis has been reported in systemic lupus erythematosus (SLE), predictive biomarkers of cardiovascular disease (CVD) are needed. Among non-traditional risk factors, bone mineral density (BMD) has been related to CVD. However, its role in SLE remains controversial. This study aims to analyze the associations of subclinical atherosclerosis with traditional and non-traditional CV risk factors.

METHODS AND RESULTS

In a cross-sectional study, atherosclerosis burden was compared between 112 female SLE patients and 31 controls. Plaque number and carotid intima-media wall thickness (cIMT) were assessed by ultrasonography. In a retrospective study, BMD determinations obtained 5-years before the ultrasonography assessment were analyzed in a subgroup of 62 patients. Plaque frequency was increased in SLE, even in patients without CV events or carotid wall thickening. cIMT was increased in patients with CVD, positively correlated with body mass index (BMI). Interestingly, a paradoxical effect of BMI on carotid parameters was observed. Whereas underweight patients (BMI < 20) showed increased prevalence of carotid plaques with low cIMT, those with BMI > 30 showed higher cIMT and plaque burden. Overweight patients (25 < BMI<30) exhibited both elevated cIMT and plaque number. BMI was an independent predictor of BMD. In our retrospective study, patients with either clinical or subclinical CVD exhibited lower BMD levels than their CV-free counterparts. A low lumbar spine BMD independently predicted CVD development after adjusting for confounders.

CONCLUSION

SLE was associated with a higher subclinical atherosclerosis burden, a bimodal effect being observed for BMI. Decreased BMD can be a CV risk biomarker in SLE.

Vitamin D status and abdominal aortic calcification in postmenopausal women

Vitamin D has an important role in bone metabolism and may be involved in the process of vascular calcification. The objective of this study was to evaluate the effect of vitamin D status on the presence of abdominal aortic calcification (AAC). We enrolled, in a cross-sectional study, 429 postmenopausal women [mean age, weight, and BMI of 59.5 ± 8.3 (50-83) years, 75.8 ± 13.3 (35-165) kg, and 29.9 ± 5.2 (14.6-50.8) kg/m², respectively]. Lateral vertebral fracture assessment (VFA) images and scans of the lumbar spine and proximal femur were obtained using a Lunar Prodigy densitometer. Vertebral fractures (VFs) were defined using the Genant semiquantitative (SQ) approach. We used the Kauppila score to assess AAC extension. Clinical risk factors of osteoporosis were collected, and 25-hydroxy vitamin D was measured using electrochemiluminescence (Roche). Prevalence of osteoporosis and hypovitaminosis D (<20 ng/ml) was 21.0% and 78.1%, respectively. VFs grade 2/3 were identified in 76 patients (17.7%). Two thirds of the evaluable participants did not have any detectable AAC. The prevalence of significant atherosclerotic burden, defined as a radiographic 24-point AAC score of 5 or higher, was 7.9%. The group of women with extended AAC were older and had a statistically significant higher menopause duration and more prevalent grade 2/3 VFs. Compared to women with normal values of vitamin D, women with vitamin D insufficiency (<20 ng/ml) and deficiency (<10 ng/ml) had a lower BMD and more prevalent VFs. No difference was noted with regard to AAC among the three groups. Multiple stepwise conditional logistic regression analysis showed that the presence of AAC was associated significantly with age and the presence of VFs. Extended aortic calcifications are independently associated with prevalent VFA-identified VFs but not with serum vitamin D levels in postmenopausal women. VFA imaging using DXA may detect at the same time prevalent VFs and AAC, an important cardiovascular disease risk factor.

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.

Cardiovascular calcifications in chronic kidney disease: Potential therapeutic implications

Cardiovascular (CV) calcification is a highly prevalent condition at all stages of chronic kidney disease (CKD) and is directly associated with increased CV and global morbidity and mortality. In the first part of this review, we have shown that CV calcifications represent an important part of the CKD-MBD complex and are a superior predictor of clinical outcomes in our patients. However, it is also necessary to demonstrate that CV calcification is a modifiable risk factor including the possibility of decreasing (or at least not aggravating) its progression with iatrogenic manoeuvres. Although, strictly speaking, only circumstantial evidence is available, it is known that certain drugs may modify the progression of CV calcifications, even though a direct causal link with improved survival has not been demonstrated. For example, non-calcium-based phosphate binders demonstrated the ability to attenuate the progression of CV calcification compared with the liberal use of calcium-based phosphate binders in several randomised clinical trials. Moreover, although only in experimental conditions, selective activators of the vitamin D receptor seem to have a wider therapeutic margin against CV calcification. Finally, calcimimetics seem to attenuate the progression of CV calcification in dialysis patients. While new therapeutic strategies are being developed (i.e. vitamin K, SNF472, etc.), we suggest that the evaluation of CV calcifications could be a diagnostic tool used by nephrologists to personalise their therapeutic decisions.

Pro: cardiovascular calcifications are clinically relevant

It is increasingly acknowledged that mineral and bone disorders (MBDs) contribute to the excessively high cardiovascular (CV) disease morbidity and mortality observed in patients with chronic kidney disease (CKD). There is ongoing debate as to whether screening for CV calcification, one of the hallmarks of CKD-MBD, should be implemented in clinical practice in patients with CKD. Issues to be considered in this controversy relate to prevalence, severity, relevance, and last but not least, modifiability and reversibility of vascular and valvular calcifications in the setting of CKD. The recent expansion of the armamentarium to treat CKD-MBD (calcium-free phosphate binders and calcimimetics) creates new opportunities. Mounting experimental and clinical evidence indicates that progression of CV calcification may indeed be attenuated. Whether this will translate into better outcomes remains to be proven. We acknowledge that hard outcome data so far are limited and, overall, yielded inconclusive results. Nevertheless, in an era in which personalized medicine has gained much popularity, we consider it reasonable, awaiting the results of additional studies, to screen for CV calcification in selected individuals. This policy may help to stratify CV risk and to guide therapy. We speculate that such an approach will ultimately improve outcomes and reduce health costs.

Abdominal aortic calcification: A reappraisal of epidemiological and pathophysiological data

In men and women, there is a significant association between the risk of cardiovascular event (myocardial infarction, stroke) and risk of major fragility fracture (hip, vertebra). Abdominal aortic calcification (AAC) can be assessed using semiquantitative scores on spine radiographs and spine scans obtained by DXA. Severe AAC is associated with higher risk of major cardiovascular event. Not only does severe AAC reflect poor cardiovascular health status, but also directly disturbs blood flow in the vascular system. Severe (but not mild or moderate) AAC is associated with lower bone mineral density (BMD), faster bone loss and higher risk of major fragility fracture. The fracture risk remains increased after adjustment for BMD and other potential risk factors. The association between severe AAC and fracture risk was found in both sexes, mainly in the follow-ups of less than 10years. Many factors contribute to initiation and progression of AAC: lifestyle, co-morbidities, inorganic ions, dyslipidemia, hormones, cytokines (e.g. inflammatory cytokines, RANKL), matrix vesicles, microRNAs, structural proteins (e.g. elastin), vitamin K-dependent proteins, and medications (e.g. vitamin K antagonists). Osteogenic transdifferentiation of vascular smooth muscle cells (VSMC) and circulating osteoprogenitors penetrating into vascular wall plays a major role in the AAC initiation and progression. Vitamin K-dependent proteins protect vascular tunica media against formation of calcified deposits (matrix GLA protein, GLA-rich protein) and against VSMC apoptosis (Gas6). Further studies are needed to investigate clinical utility of AAC for the assessment of fracture and cardiovascular risk at the individual level and develop new medications permitting to prevent AAC progression.

Abdominal aortic calcification and risk of fracture among older women - The SOF study

Data concerning the link between severity of abdominal aortic calcification (AAC) and fracture risk in postmenopausal women are discordant. This association may vary by skeletal site and duration of follow-up. Our aim was to assess the association between the AAC severity and fracture risk in older women over the short- and long term. This is a case-cohort study nested in a large multicenter prospective cohort study. The association between AAC and fracture was assessed using Odds Ratios (OR) and 95% confidence intervals (95%CI) for vertebral fractures and using Hazard Risks (HR) and 95%CI for non-vertebral and hip fractures. AAC severity was evaluated from lateral spine radiographs using Kauppila's semiquantitative score. Severe AAC (AAC score 5+) was associated with higher risk of vertebral fracture during 4 years of follow-up, after adjustment for confounders (age, BMI, walking, smoking, hip bone mineral density, prevalent vertebral fracture, systolic blood pressure, hormone replacement therapy) (OR=2.31, 95%CI: 1.24-4.30, p<0.01). In a similar model, severe AAC was associated with an increase in the hip fracture risk (HR=2.88, 95%CI: 1.00-8.36, p=0.05). AAC was not associated with the risk of any non-vertebral fracture. AAC was not associated with the fracture risk after 15 years of follow-up. In elderly women, severe AAC is associated with higher short-term risk of vertebral and hip fractures, but not with the long-term risk of these fractures. There is no association between AAC and risk of non-vertebral-non-hip fracture in older women. Our findings lend further support to the hypothesis that AAC and skeletal fragility are related.

Vascular calcification and fracture risk

Osteoporosis and cardiovascular diseases are public health problems. Fragility fractures are associated with high risk of cardiovascular event and patients with cardiovascular diseases have higher risk of fracture. Severe abdominal aortic calcification (AAC) is associated with higher cardiovascular mortality and morbidity. Severe AAC is associated with higher risk of fracture. In cross-sectional studies severe AAC was associated with greater prevalence, higher number and greater severity of vertebral fractures after adjustment for confounders including bone mineral density (BMD). Prospective studies confirm the association between baseline AAC severity and prospectively assessed fracture risk in both sexes. Data on the link between AAC and BMD are discordant. Age, smoking, hypertension, diabetes mellitus, and low grade systemic inflammation are possible risk factors of severe AAC and fracture risk. However, in clinical studies, the link between AAC and fracture was significant after adjustment for these factors. Data on the association between calcification in other vascular beds and BMD are limited and discordant.

Coronary artery calcification in chronic kidney disease: An update

Arterial calcification is a well-recognized complication of advanced atherosclerosis. Chronic kidney disease (CKD) is characterized by significantly more pronounced, disseminated and fast-progressing calcification of the vascular system, including the coronary arteries. New computed tomography-based imaging techniques allow for the noninvasive assessment and monitoring of calcification in different vascular sites. Coronary artery calcification (CAC) develops early in the course of CKD and is tightly associated with mineral and bone disorders, which include but are not limited to secondary hyperparathyroidism. In this review, recent data on the pathogenesis of CAC development and progression are discussed, with a special emphasis on fibroblast growth factor 23 and its co-receptor, klotho. The prevalence, progression and prognostic significance of CAC are reviewed separately for patients with end-stage renal disease treated with dialysis, kidney transplant recipients and patients with earlier stages of CKD. In the last section, therapeutic considerations are discussed, with special attention paid to the importance of treatment that addresses mineral and bone disorders of CKD.

Association of matrix Gla protein gene functional polymorphisms with loss of bone mineral density and progression of aortic calcification

Two matrix Gla protein (MGP) polymorphisms were associated with progression of aortic calcification and femoral neck bone loss in men. All these findings were also functionally corroborated in two vascular and bone in vitro systems indicating that MGP genetic variations can be partly responsible of higher risk of bone loss and vascular calcification.

INTRODUCTION

MGP plays an important role in bone and vascular mineralization as confirmed by MGP-deficient murine model. We therefore aimed to find a genetic association among -138T>C, -7G>A, and Thr83Ala MGP single-nucleotide polymorphisms (SNPs), bone loss, and progression of aortic calcification in a randomly selected general population of 296 individuals who participated in the European Vertebral Osteoporosis Study.

METHODS

To evaluate the rate of change in bone mineral density (BMD) and the progression of aortic calcification, dual X-ray absorptiometry and lateral spine X-rays were performed at baseline and after 4 years of follow-up. Genotyping for the three polymorphisms was carried out using polymerase chain reaction and restriction fragment length analysis. In addition, functional studies of MGP-7G>A and Thr83Ala SNPs were performed on transiently transfected osteoblast-like UMR-106 and vascular smooth muscle A7r5 cells.

RESULTS

The proportion of men who had lost BMD in the femoral neck was higher among homozygous -7AA and 83Ala-Ala (p = 0.039 and p = 0.009, respectively), and also featured a higher risk of progression of aortic calcifications (OR = 5.6, 95% CI = 1.2-27.8 and OR = 6.8, 95% CI = 1.4-32.3, respectively). No effect was observed in women. The MGP-7A allele produced a reduction in luciferase activity compared to MGP-7G: 47% less in vascular cells and 34% less in bone cells (p = 0.001 and 0.012, respectively). In vascular cells under calcifying conditions, the MGP 83Thr allele showed a slightly higher, although not significant, inhibition than the MGP 83 Ala allele in calcium content suggesting functional differences between both variants.

CONCLUSION

These results suggest that MGP genetic variations could predict a higher risk of bone loss and progression of vascular calcification in men.

High hip fracture risk in men with severe aortic calcification: MrOS study

A significant link between cardiovascular disease and osteoporosis is established in postmenopausal women, but data for men are scarce. We tested the hypothesis that greater severity of abdominal aortic calcification (AAC) was associated with an increased risk of nonspine fracture in 5994 men aged ≥ 65 years. AAC was assessed on 5400 baseline lateral thoracolumbar radiographs using a validated visual semiquantitative score. Total hip bone mineral density (BMD) was measured using dual-energy X-ray absorptiometry. Incident nonspine fractures were centrally adjudicated. After adjustment for age, body mass index (BMI), total hip BMD, fall history, prior fracture, smoking status, comorbidities, race, and clinical center, the risk of nonspine fracture (n=805) was increased among men with higher AAC (hazard ratio [HR] quartile 4 [Q4] [AAC score ≥ 9] versus quartile 1 [Q1] [0-1], 1.36; 96% confidence interval [CI], 1.10-1.68). This association was due to an increased risk of hip fracture (n=178) among men with higher AAC (HR Q4 versus Q1, 2.33; 95% CI, 1.41-3.87). By contrast, the association between AAC and the risk of nonspine, nonhip fracture was weaker and not significant (HR Q4 versus Q1, 1.22; 95% CI, 0.96-1.55). The findings regarding higher AAC and increased risk of fracture were not altered in additional analyses accounting for degree of trauma, estimated glomerular filtration rate, presence of lumbar vertebral fractures (which may bias AAC assessment), preexisting cardiovascular disease, ankle brachial index, or competing risk of death. Thus, in this large cohort of elderly men, greater AAC was independently associated with an increased risk of hip fracture, but not with other nonspine fractures. These findings suggest that AAC assessment may be a useful method for identification of older men at high risk of hip fracture.

Vitamin D and the cardiovascular system: an overview of the recent literature

Since the discovery that the enzyme catalyzing the synthesis of the most active natural vitamin D metabolite(calcitriol) and the vitamin D-specific receptor (VDR)were expressed in a wide range of tissues and organs, not only involved in the mineral metabolism (MM), there has been increasing interest on the putative ‘non classical’ roles of vitamin D metabolites, particularly on their possible effects on the cardiovascular (CV) system. These hypothetical CV effects of vitamin D gained particular interesting the nephrology field, given the high prevalence of CV disease in patients affected by either acute or chronic kidney diseases. However, notwithstanding a huge amount of experimental data suggesting a possible protective role of vitamin D on the CV system, the conclusions of two recent meta-analyses from the Cochrane group and a recent statement from the Institute of Medicine, based on a complete revision of the available data, concluded that there is no clear evidence for a role of vitamin D other than that strictly associated with bone health. However, a continuous and increasing flow of new studies still continues to add information on this topic. In the present review, we have tried to critically address the data added on this topicin the last 2 years, considering separately the experimental,observational, and intervention studies that have appeared in PubMed in the last 2 years, discussing the data providing proof, pro or contra, the involvement of vitamin D in CV disease, both in the absence or presence of kidney function impairment.

Severe abdominal aortic calcification in older men is negatively associated with DKK1 serum levels: the STRAMBO study

CONTEXT

Experimental data show that dickkopf-1 (DKK1) may be involved in the regulation of arterial calcification. However, clinical data on the association between serum DKK1 levels and severity of abdominal aortic calcification (AAC) are scarce.

OBJECTIVE

Our aim was to determine the association between serum DKK1 concentration and AAC severity in men.

DESIGN

This is a cross-sectional analysis in the STRAMBO cohort.

SETTING

The cohort was recruited from the general population.

PARTICIPANTS

We examined 1139 male volunteers aged 20 to 87 years. No specific exclusion criteria were used.

INTERVENTIONS

We collected blood samples and assessed AAC severity on the lateral spine scans obtained by a Discovery A Hologic device using the semiquantitative Kauppila score.

MAIN OUTCOME MEASURES

We tested the hypothesis that low DKK1 levels are associated with AAC severity in men.

RESULTS

In men aged 20 to 60 years, serum DKK1 levels were not associated with other variables. In men aged 60 years and older, lower DKK1 levels were associated with higher odds of severe AAC (AAC score >5). After adjustment for confounders, odds of severe AAC increased with decreasing DKK1 levels (odds ratio = 1.42, 95% confidence interval = 1.13-1.79, P < .005) and was higher below vs above the median DKK1 level (odds ratio = 2.19, 95% confidence interval = 1.37-3.49, P < .005). Heavy smoking, hypertension, ischemic heart disease, and elevated levels of fibroblast growth factor 23 were associated with severe AAC significantly, independently of DKK1 and additively with low DKK1 levels.

CONCLUSION

In older men, lower serum DKK1 levels are associated with severe AAC regardless of age and other potential confounders.

Immune, metabolic and epidemiological aspects of vitamin D in chronic kidney disease and transplant patients

Chronic kidney disease strongly impacts on mineral and bone metabolism. Despite numerous medications, the biological targets recommended by international guidelines are often unmet. Among the treatment armamentarium, native or nutritional vitamin D (25OHD3) has been rediscovered in the early 2000s, and its general and specific actions further studied. Effects on bone, immunity, infection prevention, muscle function and phosphocalcic metabolism have been reviewed. Assessment of nutritional vitamin D status showed very low serum 25OHD3 levels and increase in nutritional vitamin D prescription led to improvement in these levels. However, about 45% of adult CKD patients still have insufficient serum 25OHD3 levels. Epidemiological studies should be enforced to describe further the mineral and bone disease management in CKD.

Higher serum osteocalcin is associated with lower abdominal aortic calcification progression and longer 10-year survival in elderly men of the MINOS cohort

CONTEXT

Abdominal aortic calcification (AAC) is an indicator of cardiovascular risk, especially in the diseases characterized by insulin resistance such as type 2 diabetes. Osteocalcin is a bone-secreted hormone that favors insulin sensitivity and insulin secretion.

OBJECTIVES

We investigated whether total serum osteocalcin level at baseline is associated with AAC progression and 10-year all-cause mortality in elderly men.

DESIGN AND PARTICIPANTS

We assessed 774 men aged 51-85 years from the MINOS cohort who had osteocalcin measurement and lumbar spine radiographs at baseline. They were followed-up prospectively for 10 years. Among them, 615 patients had a follow-up radiograph at 3.5 or 7 years.

MAIN OUTCOME MEASURES

Serum total osteocalcin was measured with an immunoradiometric assay on morning fasting serum collected at baseline. Kauppila's AAC score was assessed from lumbar spine radiographs. AAC progression rate was calculated as the difference between AAC on the last available radiograph and AAC at baseline divided by the follow-up time. Death status was collected over 10 years.

RESULTS

In multivariate analysis, higher baseline total osteocalcin was associated with lower AAC progression rate (odds ratio = 0.74 [0.57-0.97] per 10 ng/mL variation; P = 0.029). At the 10-year follow-up, there were 599 men alive (77%), 181 dead (23%), and 2 lost to follow-up. Higher osteocalcin was associated with lower 10-year all-cause mortality (hazard ratio = 0.62 [0.44-0.86] per 10 ng/mL variation; P = 0.005).

CONCLUSION

Higher baseline total osteocalcin concentrations were associated with lower AAC progression rate and lower mortality. These data suggest that osteocalcin level might be an independent indicator of cardiovascular risk and global health in elderly Caucasian men.

Serum myostatin levels are negatively associated with abdominal aortic calcification in older men: the STRAMBO study

OBJECTIVE

To assess the association between abdominal aortic calcification (AAC) and serum levels of myostatin, a negative regulator of skeletal muscle mass, which has been implicated in the development of atherosclerotic lesions in mice.

DESIGN AND PATIENTS

We assessed AAC semiquantitatively from the lateral spine scans obtained using dual energy X-ray absorptiometry in 1071 men aged 20-87 years. Serum myostatin levels were measured by an immunoassay that detects all myostatin forms.

RESULTS

Total myostatin serum levels did not differ between men with or without self-reported ischemic heart disease, hypertension, or diabetes mellitus. Total serum myostatin levels were higher in men with higher serum calcium levels and lower in men with higher serum concentrations of highly sensitive C-reactive protein. Men with AAC had lower myostatin levels compared with men without AAC. Prevalence of AAC (AAC score > 0) was lower in the highest myostatin quartile compared with the three lower quartiles (P < 0.05). After adjustment for confounders, odds of AAC (AAC score > 0) were lower (OR=0.62; 95% confidence interval (95% CI), 0.45-0.85; P< 0.005) for the fourth myostatin quartile vs the three lower quartiles combined. In the sub-analysis of 745 men aged 60 years, the results were similar: AAC prevalence was lower in the highest myostatin quartile compared with the three lower quartiles combined (OR=0.54; 95% CI, 0.38-0.78; P<0.001).

CONCLUSIONS

In older men, total myostatin serum levels are inversely correlated with AAC. Further studies are needed to investigate mechanisms underlying this association and to assess utility of myostatin as a cardiovascular marker.

Association between cardiovascular diseases and osteoporosis-reappraisal

Positive association between cardiovascular diseases and osteoporosis is important because it concerns two major public health problems. Men and women with cardiovascular diseases (including severe abdominal aortic calcification (AAC) and peripheral arterial disease) tend to have lower areal and volumetric bone mineral density (BMD) as well as faster bone loss, although findings vary according to skeletal site. On one hand, severe forms of cardiovascular diseases (heart failure, myocardial infarction, hypertension, severe AAC) are associated with higher risk of osteoporotic fracture, especially hip fracture. This link was found in the studies based on healthcare databases and the cohort studies. On the other hand, low BMD, history of fragility fracture, vitamin D deficit and increased bone resorption are associated with higher risk of major cardiovascular events (myocardial infraction, stroke, cardiovascular mortality). Moreover, osteocalcin secreted by osteoblasts may be involved in the regulation of energetic and cardiovascular metabolism. The association between both pathologies depends partially on the shared risk factors, and also on the mechanisms that are involved in the regulation of bone and cardiovascular metabolism. Interpretation of the data should take into account methodological limitations: representativeness of the cohorts, quality of the registers and the information obtained from questionnaires, severity of diseases, number of events (statistical power) and their temporal closeness, availability of the information on potential confounders. It seems that patients with severe form of osteoporosis would benefit from assessment of the cardiovascular status and vice versa. However, official guidelines for the clinical practice are still lacking.