Aortic Stiffness and Vitamin D are Independent Markers of Aortic Calcification in Patients with Peripheral Arterial Disease and in Healthy Subjects

Serum biomarkers for arterial calcification in humans: A systematic review

Aim

To clarify the role of mediators of ectopic mineralization as biomarkers for arterial calcifications.

Methods

MEDLINE and Embase were searched for relevant literature, until January 4th 2022. The investigated biomarkers were: calcium, phosphate, parathyroid hormone, vitamin D, pyrophosphate, osteoprotegerin, receptor activator of nuclear factor-kappa B ligand (RANKL), fibroblast growth factor-23 (FGF-23), Klotho, osteopontin, osteocalcin, Matrix Gla protein (MGP) and its inactive forms and vitamin K. Studies solely performed in patients with kidney insufficiency or diabetes mellitus were excluded.

Results

After screening of 8985 articles, a total of 129 articles were included in this systematic review. For all biomarkers included in this review, the results were variable and more than half of the studies for each specific biomarker had a non-significant result. Also, the overall quality of the included studies was low, partly as a result of the mostly cross-sectional study designs. The largest body of evidence is available for phosphate, osteopontin and FGF-23, as a little over half of the studies showed a significant, positive association. Firm statements for these biomarkers cannot be drawn, as the number of studies was limited and hampered by residual confounding or had non-significant results. The associations of the other mediators of ectopic mineralization with arterial calcifications were not clear.

Conclusion

Associations between biomarkers of ectopic mineralization and arterial calcification are variable in the published literature. Future longitudinal studies differentiating medial and intimal calcification could add to the knowledge of biomarkers and mechanisms of arterial calcifications.

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We researched the association between biomarkers and arterial calcifications.

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This review focused on biomarkers of bone metabolism and Matrix Gla protein.

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Associations between biomarkers and arterial calcification are variable.

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Future studies should differentiate between medial and intimal calcifications.

Vitamin D equilibrium affects sex-specific changes in lipid concentrations during Christian Orthodox fasting

We aimed to evaluate sex differences in changes of lipid profiles in a cohort of metabolically healthy adults following Orthodox fasting (OF), as well as to assess a potential role of vitamin D status in mediating these variations. 45 individuals (24 premenopausal females, 53.3 %) with mean age 48.3 ± 9.1 years and mean Body Mass Index 28.7 ± 5.8 kg/m² were prospectively followed for 12 weeks. Anthropometry, dietary and biochemical data regarding serum lipids, and vitamin D status were collected at baseline, 7 weeks after the implementation of OF, and 5 weeks after fasters returned to their standard dietary habits (12 weeks from baseline). According to 25-hydroxy-vitamin D [25(OH)D] measurements, participants were divided into two groups: those with concentrations above and below the median of values. Females with 25(OH)D concentrations below the median manifested a non-significant reduction by approximately 15 % in total and low-density lipoprotein cholesterol during the fasting period, followed by a significant increase 5 weeks after OF cessation (170.7 vs. 197.5 and 99.6 vs. 121.0 mg/dl respectively, p < 0.001). In contrast, males with 25(OH)D levels below the median demonstrated an inverse, non-significant trend of increase in lipid concentrations during the whole study period. Our findings suggest strikingly different inter-gender lipid responses to a dietary model of low-fat, mediated by vitamin D status. Further studies are necessary to reveal the underlying mechanisms and assess the importance of these differences with respect to cardiovascular health and the benefit of vitamin D supplementation strategies.

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

[Figure: see text].

Vitamin D serum levels and peripheral arterial disease among southern Brazilian adults

OBJECTIVE

To investigate the association between low serum vitamin D levels and peripheral arterial disease (PAD).

METHODS

A cross-sectional study with a consecutive sample of 133 individuals from Caxias do Sul, Brasil. We considered PAD patients those with an ankle-brachial index (ABI) ≤ 0.90 or with arterial revascularization. Vitamin D serum level was categorized as sufficient (≥30 ng/mL), insufficient (>20 to 29 ng/mL), and deficient (<20 ng/mL). Prevalence ratios (RP) were calculated through Poisson regression.

RESULTS

The prevalence of PAD was 50.7% (95% CI 42-59). After adjustment for potential PAD risk factors, RP were 1.08 (95% CI 0.66-1.76) for insufficient serum level and 1.57 (95% CI 0.96-2.57) for deficient vitamin D serum level; (p for trend = 0.020).

CONCLUSION

Vitamin D serum levels showed an inverse and significant dose-response relationship with PAD.

Vitamin D and Abdominal Aortic Calcification in Older African American Women, the PODA Clinical Trial

Abdominal aortic calcification (AAC) detected on lateral vertebral fracture assessment is associated with increased cardiovascular risk. Vitamin D deficiency and toxicity have been linked with vascular calcification. The objective of this study was to determine the effect of high-dose vitamin D on the progression of AAC. The Physical Performance, Osteoporosis and vitamin D in African American Women (PODA) is a randomized, clinical trial examining the effect of vitamin D. There were 14.7% subjects with AAC in the vitamin D group, compared to 12.1% in the placebo group at baseline. The prevalence of extended AAC at baseline was 6.4% in the vitamin D group and 3.5% in the placebo group. The extended calcification scores over time were not different between groups. There was no association between AAC and serum 25(OH)D. However, PTH was associated with an increase in AAC in the placebo group.

Vitamin D as A Protector of Arterial Health: Potential Role in Peripheral Arterial Disease Formation

Atherosclerotic occlusive diseases and aneurysms that affect large and medium-sized arteries outside the cardiac and cerebral circulation are collectively known as peripheral arterial disease (PAD). With a rise in the rate of aging population worldwide, the number of people diagnosed with PAD is rapidly increasing. The micronutrient vitamin D is an important steroid hormone that acts on many crucial cellular mechanisms. Experimental studies suggest that optimal levels of vitamin D have beneficial effects on the heart and blood vessels; however, high vitamin D concentrations have been implicated in promoting vascular calcification and arterial stiffness. Observations from various clinical studies shows that deficiency of vitamin D has been associated with a greater risk of PAD. Epidemiological studies have often reported an inverse relation between circulating vitamin D status measured in terms of 25-hydroxivitamin D [25(OH)D] levels and increased cardiovascular disease risk; however, randomized controlled trials did not show a consistent positive effect of vitamin D supplementation on cardiovascular disease risk or events. Even though PAD shares all the major risk factors with cardiovascular diseases, the effect of vitamin D deficiency in PAD is not clear. Current evidence suggests a strong role of vitamin D in promoting genomic and epigenomic changes. This review summarises the current literature that supports the notion that vitamin D deficiency may promote PAD formation. A better understanding of underlying pathological mechanisms will open up new therapeutic possibilities which is the main unmet need in PAD management. Furthermore, epigenetic evidence shows that a more holistic approach towards PAD prevention that incorporates a healthy lifestyle, adequate exercise and optimal nutrition may be more effective in protecting the genome and maintaining a healthy vasculature.

Vitamin D deficiency is associated with risk of developing peripheral arterial disease in type 2 diabetic patients

Background

The relationship between vitamin D levels and peripheral arterial disease (PAD) remains unclear. We assessed the association of serum 25-hydroxyvitamin D (25(OH)D) levels with the prevalence of PAD in patients with type 2 diabetes mellitus(T2DM).

Methods

A total of 1018 T2DM patients participated in this cross-sectional study. Serum 25(OH)D levels were measured and risk factors of PAD were recorded. PAD was diagnosed as an ankle-brachial index (ABI) < 0.9.

Results

The mean age of the diabetic patients was 58.59 ± 11.34 years. Of all the patients, only 20.1% had a 25(OH)D level ≥ 20 ng/mL. Compared to patients without PAD, serum 25(OH)D levels were significantly lower in those with PAD (14.81 ± 8.43 vs. 11.55 ± 5.65 ng/mL, P < 0.001). The overall prevalence of PAD was 7.7%. From the highest level (≥ 20 ng/mL) to the lowest level (< 10 ng/mL) of serum 25(OH)D, the prevalence of PAD was 2.8, 7.5 and 10.7% respectively. After adjustment for age, sex, body mass index (BMI), smoking status and season, compared to patients with serum 25(OH)D levels ≥20 ng/mL, the odds ratios of PAD in patients with a level of 10 to < 20 ng/mL and < 10 ng/mL was 3.587(95% CI: 1.314–9.790) and 5.540(95% CI: 2.004–15.320), respectively. When further considering the influence of coronary heart disease (CHD), hypertension and cerebral infarction, the ratios changed to 3.824(95% CI: 1.378–10.615) and 5.729(95% CI: 2.028–16.187), respectively. And after further adjustment for the duration of diabetes, glycated hemoglobin (HbA1c) and glomerular filtration rate (GFR), the ratios changed to 3.489(95% CI: 1.100–11.062) and 3.872(95% CI: 1.168–12.841), respectively.

Conclusions

Reduced serum vitamin D levels were associated with an increased risk of PAD in T2DM patients. Randomized interventive clinical studies are required to verify the effects of vitamin D supplementation on PAD.

Vitamin D and cardiovascular disease

Vitamin D, a soluble steroid hormone synthesized in the skin after sun exposure, plays a crucial role in calcium metabolism and is also involved in cardiovascular pathophysiology. The aim of this review is to summarize the available evidence (a) on the association between endogenous vitamin D status and cardiovascular disease, and (b) on the effect of vitamin D supplementation on cardiovascular outcomes. Most studies have shown an inverse association between vitamin D levels and cardiovascular outcomes. Randomized controlled trials, however, do not consistently support a beneficial effect of vitamin D administration on cardiovascular health. Population characteristics, comorbid conditions such as diabetes, the overall population prevalence of cardiovascular disease, vitamin D status and the regimen of vitamin D supplementation may account for the conflicting results.

Vitamin D Deficiency, Supplementation, and Cardiovascular Health

Vitamin D has been traditionally recognized as a vitamin quintessential for bone-mineral health. In the past 2 decades, numerous experimental and observational studies have highlighted the role of vitamin D in immunity, metabolic syndrome (obesity and diabetes), cancers, renal disease, memory, and neurological dysfunction. In this article, we review important studies that focused on the impact of vitamin D on blood pressure, myocardial infarction, peripheral arterial disease, heart failure, and statin intolerance. Amidst the current pool of ambiguous evidence, we intend to discuss the role of vitamin D in "high-value cardiovascular health care".

The relationship between pulse waveform analysis indices, endothelial function and clinical outcomes in patients with peripheral artery disease treated using percutaneous transluminal angioplasty during a one-year follow-up period

BACKGROUND

Several predictors of clinical outcomes after percutaneous transluminal angioplasty (PTA) interventions in patients with peripheral arterial disease (PAD) have been investigated. Indices of endothelial function, arterial pulse waveform analysis (aPWA) and markers of peripheral artery ischemia were among the most commonly examined. The aim of the current study was to assess the relationship between potential predictors of clinical outcomes after peripheral artery PTA during a 1-year follow-up period.

METHODS

The study included 72 individuals with PAD at a mean age of 66.3 ± 7.2 (79.1% males). All patients underwent PTA of the peripheral arteries. Among them, 42.8% presented critical limb ischemia (CLI). During the first visit and at 1 month and 6 months after PTA, endothelial function and aPWA measurements were taken. Ankle-brachial index (ABI), toe-brachial index (TBI) and physical evalu-ation of the limbs took place during the first visit and at 1, 6 and 12 months after the PTA. The study endpoints included myocardial infarction, amputation, death, stroke and reintervention. All subjects included in the study were observed for 386 days after the PTA.

RESULTS

A significant improvement was noted in walking distance after PTA at the following time points, as well as transient improvement of ABI and flow-mediated dilatation (FMD) and no significant change in aPWA indices and reactive-hyperaemia index (RHI). The mean ABI, TBI, FMD and RHI values did not correlate with each other at baseline. There were 25 study endpoints which occurred in 16 patients during the follow-up period (22.2%). Patients with CLI, hypercholesterolemia, lower dias-tolic blood pressure, higher subendocardial viability ratio, a greater number of pack-years and lower TBI at baseline presented significantly poorer clinical outcomes in terms of endpoint events.

CONCLUSIONS

Endothelial function assessed as FMD and reactive hyperemia-peripheral arterial tonometry (RH-PAT) before PTA in patients with advanced PAD do not predict clinical outcomes during the 1-year follow-up.

Association of Vitamin D deficiency with peripheral arterial disease: a meta-analysis of literature studies

CONTEXT

Vitamin D deficiency patients have an increased cardiovascular (CV) morbidity and mortality. Contrasting data are available about the association between peripheral arterial disease (PAD) and Vitamin D status.

OBJECTIVE

To perform a meta-analysis of studies evaluating the association between Vitamin D status and PAD.

DATA SOURCES

Studies were systematically searched in the PubMed, Web of Science, Scopus and EMBASE databases.

RESULTS

Ten studies with data on Vitamin D levels in 2,079 PAD patients and 18,233 non-PAD controls and 6 studies on the prevalence of PAD in 23,171 subjects with Vitamin D deficiency (<20 ng/ml), 48,311 subjects with Vitamin D insufficiency (20-30 ng/ml) and 27,910 with normal Vitamin D levels (>30 ng/ml) were included. Compared to controls, PAD patients showed significantly lower Vitamin D levels (MD: -2.24 ng/ml; 95%CI: -3.38, -1.10; p<0.001, I2=86.5%; p<0.001). Moreover, a higher prevalence of PAD was found both in subjects with Vitamin D insufficiency (OR: 1.098, 95%CI: 1.010-1.195, p=0.029, I2: 0%, p=0,600) and in subjects with Vitamin D deficiency (OR: 1.484, 95%CI: 1.348-1.635, p<0.001, I2: 7.65%, p=0,367) compared with controls with normal Vitamin D levels. Sensitivity analyses and the analysis of data on the cumulative risk of PAD according to Vitamin D levels derived from multivariate analysis consistently confirmed results.

CONCLUSIONS

PAD patients have lower vitamin D levels than controls and both Vitamin D deficiency and Vitamin D insufficiency are significantly associated with PAD. Reduced Vitamin D levels might represent an independent risk factor for PAD and, in turn, for CV events.

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.

Vitamin D and Cardiovascular Disease: Controversy Unresolved

Vitamin D deficiency is typically caused by inadequate cutaneous synthesis secondary to decreased exposure to sunlight. Serum levels of 25-hydroxyvitamin D l <20 ng/ml are diagnostic of vitamin D deficiency. Vitamin D has various cardiovascular pleiotropic effects by activating its nuclear receptor in cardiomyocytes and vascular endothelial cells and by regulating the renin-angiotensin-aldosterone system, adiposity, energy expenditure, and pancreatic cell activity. In humans, vitamin D deficiency is associated with the following: vascular dysfunction; arterial stiffening; left ventricular hypertrophy; and worsened metrics of diabetes, hypertension, and hyperlipidemia. It is also linked with worse cardiovascular morbidity and mortality. However, meta-analyses of vitamin D supplementation trials have failed to show clear improvements in blood pressure, insulin sensitivity, or lipid parameters, thus suggesting that the link between vitamin D deficiency and cardiovascular disease may be an epiphenomenon. Ongoing larger randomized trials will clarify whether monitoring and supplementation of vitamin D play roles in cardiovascular protection.

Automated oscillometric blood pressure and pulse-wave acquisition for evaluation of vascular stiffness in atherosclerosis

OBJECTIVE

Evaluation of diagnostic accuracy of an oscillometry-based device (VascAssist) combining fully automated ankle-brachial index (ABI) and pulse-wave velocity (PWV) assessment for detection of peripheral arterial disease (PAD).

SUBJECTS AND METHODS

110 consecutive subjects including symptomatic PAD patients (n = 41) and healthy PAD-free participants (n = 69) were recruited. All subjects underwent standard manual Doppler-based ABI (sABI) and oscillometry-based automated ABI (aABI) measurements (VascAssist). Oscillometry by the VascAssist included central and peripheral PWV assessment. Additionally, arterial stiffness (AS) was evaluated by flow-mediated vasodilation (FMD) of the brachial artery in all patients. All symptomatic PAD patients underwent catheter angiography for endovascular intervention and post-interventional acquisition of sABI, aABI, PWV and FMD.

RESULTS

Sensitivity, specificity, PPV and NPV of aABI for detecting PAD was 73%, 100%, 100%, and 86% as compared to 80%, 96%, 92%, and 89% for sABI. Pearson-correlation for diabetics was r = 0.81; (P < .001) and for non-diabetics r = 0.77; (P < .001). Bland-Altman-analysis revealed a difference (95% CI) for diabetics of 0.09 (-0.22-0.4] and non-diabetics 0.022 [-0.25-0.295]. Weak correlation exists for FMD/AS analysis (pre-interventional R = 0.386, P = .043; post-interventional R = -0.06; P = .76) and significant increase of pre-/post-interventional PWV analysis (P < .001).

CONCLUSION

Combined automatic ABI and PWV acquisition with the VascAssist device showed excellent diagnostic accuracy for detection of PAD. Compared to FMD, AS analysis may serve as an investigator-independent (screening) tool for determination of functional vascular damage in atherosclerosis.

Dietary intake and peripheral arterial disease incidence in middle-aged adults: the Atherosclerosis Risk in Communities (ARIC) Study

Background: Peripheral arterial disease (PAD) is a costly source of morbidity and mortality among older persons in the United States. Dietary intake plays a role in the development of atherosclerotic cardiovascular disease; however, few studies have examined the relation of food intake or dietary patterns with PAD.Objective: We examined the relation between habitual dietary intake at midlife and incident PAD over ∼20 y of follow-up.Design: Among 14,082 participants enrolled in the ARIC (Atherosclerosis Risk in Communities) Study initially free of PAD, dietary intake was assessed at baseline in 1987-1989 by using a modified Harvard food-frequency questionnaire. Food groups were created, and principal components analysis was used to develop "healthy" and "Western" dietary patterns; both were categorized into quintiles or quartiles. Incident PAD was determined by an ankle-brachial index <0.9 assessed at 2 subsequent examinations and hospital discharge codes through 2012. Multivariate-adjusted Cox proportional hazards regression was used.Results: During a mean follow-up of 19.9 y, 1569 participants developed incident PAD. In models adjusted for demographic characteristics, behaviors, and food groups, the HRs (95% CIs) for incident PAD increased across quintiles of meat consumption [quintile 1: reference, quintile 2: 1.38 (1.16, 1.65), quintile 3: 1.38 (1.16, 1.65), quintile 4: 1.45 (1.20, 1.74), quintile 5: 1.66 (1.36, 2.03); P-trend <0.001]. Compared with those who drank no alcohol, those who had 1-6 drinks/wk had a lower risk of incident PAD [0.78 (0.68, 0.89)]. For coffee, ≥4 cups/d compared with none was inversely associated with incident PAD [quintile 5 compared with quintile 1: 0.84 (0.75, 1.00); P-trend = 0.014]. There was no association between other food groups or patterns and incident PAD.Conclusions: In this prospective cohort study, greater meat consumption was associated with a higher risk, and moderate alcohol consumption was associated with a lower risk of incident PAD. Whether these associations are causal remains to be seen. This trial was registered at clinicaltrials.gov as NCT00005131.

Increased Aortic Calcification Is Associated With Arterial Stiffness Progression in Multiethnic Middle-Aged Men

Arterial stiffness is established as an independent predictor of cardiovascular morbidity and mortality. The objective was to prospectively evaluate association of aortic calcification burden with progression of arterial stiffness in population-based samples of healthy middle-aged men from ERA JUMP cohort (Electron-Beam Computed Tomography and Risk Factor Assessment in Japanese and US Men in the Post-World War II Birth Cohort). Men (n=635) aged 40 to 49 years (207 white American, 45 black American, 142 Japanese American, and 241 Japanese in Japan) were examined at baseline and 4 to 7 years later. Aortic calcification was evaluated from level of aortic arch to iliac bifurcation. Arterial stiffness progression was measured as annual change in brachial-ankle pulse wave velocity. Multivariable-adjusted general linear models were applied to investigate associations of longitudinal change in aortic calcification with arterial stiffness progression in participants overall, as well as in subgroups without or with prevalent aortic calcification at baseline. Annual change in aortic calcification was positively and significantly associated with arterial stiffness progression. In participants with annual changes in aortic calcium score of ≤0, 1 to 10, 11 to 100, and >100, the adjusted means (SD) for the annual change in brachial-ankle pulse wave velocity were 3.8 (2.2), 7.2 (2.2), 12.2 (1.8), and 15.6 (2.6) cm/s, respectively (P for trend <0.01) adjusted for baseline aortic calcification, arterial stiffness, and standard cardiovascular risk factors. Arterial stiffness was associated with the incidence of aortic calcification over the follow-up period among participants without aortic calcification (n=297) and with an increase in aortic calcification among participants with prevalent aortic calcification at baseline (n=388). Our findings suggest aortic calcification may be causally linked to arterial stiffness.

Vitamin D and cardiovascular disease: From atherosclerosis to myocardial infarction and stroke

There continues to be interest in understanding the role of vitamin D in the pathogenesis, epidemiology and prevention of cardiovascular disease (CVD). In fact vitamin D deficiency has been associated to an increased risk of developing CVD given to the relationship between low vitamin D levels and obesity, diabetes mellitus, dyslipidaemia, endothelial dysfunction and hypertension. However, although vitamin D has been identified as a potentially important marker of CVD, the mechanisms through which vitamin D deficiency leads from endothelial dysfunction to myocardial infarction and stroke are not fully understood. Thus, the goal of this review is to provide an updated review of the literature on the basic science of how vitamin D may affect the cardiovascular system and in particular to analyze the role that vitamin D may have in the whole dynamic process from the initiation of endothelial dysfunction to the development of myocardial infarction and stroke.

Association between Vitamin D Status and Risk of Peripheral Arterial Disease: The Dong-gu Study

Low levels of vitamin D have been associated with increased cardiovascular disease risk. However, few studies have evaluated the association between vitamin D status and peripheral arterial disease (PAD). We therefore aimed to investigate whether low 25-hydroxyvitamin D (25(OH)D) levels were associated with increased risk of PAD in the Korean population. This cross-sectional study was conducted among 8,960 subjects aged 50 years or older without known myocardial infarction or stroke. PAD was defined by an ankle brachial blood pressure index <0.9. Multivariate logistic regression was used to evaluate the association between serum 25(OH)D levels and risk of PAD. Of the 8,960 subjects, 3.0% had PAD and the age and sex adjusted prevalence of PAD decreased with the increasing 25(OH)D quartile. After adjusting for potential confounders and parathyroid hormones, serum 25(OH)D levels were associated with a significantly decreased risk of PAD (OR for one SD increase, 0.98; 95% CI, 0.95-1.0, P for trend=0.040). Compared with the first 25(OH)D quartile, the odds of PAD were 0.86 (95% CI, 0.62-1.21), 0.67 (95% CI, 0.46-0.97), and 0.71 (95% CI, 0.49-1.04) for the second, third, and fourth quartiles, respectively. In this cross-sectional study, we found that low serum 25(OH)D levels were associated with an increased risk of PAD, independent of traditional cardiovascular risk factors and parathyroid hormone. Our findings suggest that low vitamin D levels may contribute to PAD in the Korean population.

Lower Extremity Arterial Calcification as a Predictor of Coronary Atherosclerosis in Patients with Peripheral Arterial Disease

Background

Until now, there has been no study on the relationship between the calcification of the lower extremity arteries and significant coronary arterial disease (CAD).

Objectives

To evaluate whether lower extremity calcium scores (LECS) are associated with CAD and whether this can predict multivessel-CAD in patients with peripheral arterial disease (PAD).

Patients and Methods

We retrospectively enrolled 103 PAD patients without cardiac symptoms or known CAD. All patients underwent cardiac computed tomography (CT) and lower extremity CT within 1 month and were categorized as nonsignificant CAD, single-CAD, or multivessel-CAD. The coronary calcium scores (CCS) were quantitatively measured according to the Agatston method and LECS were semi-quantitatively measured according to the presence of lower extremity calcification in the segment. The extent of CAD was evaluated according to the presence of ≥ 50% luminal diameter stenosis in the segment of CAD.

Results

LECS in multivessel-CAD were significantly higher than those in nonsignificant CAD (10.0 ± 5.8 versus 4.0 ± 3.1, P < 0.001). LECS significantly correlated with CCS (r = 0.831, P < 0.001) and the extent of CAD (r = 0.631, P < 0.001). Multivariate regression analysis demonstrated LECS and log-transformed CCS were independent predictors for multivessel-CAD. In receiver operating characteristic curve analysis, the diagnostic performance of LECS was 0.807 (95% confidence interval = 0.724-0.891, P < 0.001) for predicting multivessel-CAD.

Conclusion

Peripheral arterial calcification is significantly correlated with CAD extent in patients with PAD. Peripheral arterial calcification can be a useful marker for predicting multivessel-CAD.

Nutritional status and body composition in patients with peripheral arterial disease: A cross-sectional examination of disease severity and quality of life

Nutritional and body weight recommendations for cardiovascular diseases are well established, yet there are no equivalent guidelines for peripheral arterial disease (PAD). This cross-sectional study measured the prevalence of cardiovascular-related nutritional and body composition risk factors in sixty PAD patients and their association with PAD severity. A diet that exceeds daily recommended intake of fat and that falls short of recommended intakes of fiber, folate, and vitamin D was associated with increased leg pain and walking difficulty. Increased body fat and waist circumference were associated with diminished walking ability and poorer psychosocial quality of life. Future prospective investigations are merited to inform both PAD clinical care and disease management guidelines.

The association of circulating 25-hydroxyvitamin D concentration with peripheral arterial disease: A meta-analysis of observational studies

BACKGROUND AND AIMS

The association of vitamin D deficiency with cardiovascular disease is controversial. The present meta-analysis was performed to examine if circulating levels of 25-hydroxyvitamin D [25(OH)D] were lower in patients with peripheral artery disease (PAD) when compared to non-PAD controls.

METHODS

A comprehensive database search was conducted in Web of science, Scopus, PubMed, EMBASE and The Cochrane Library to identify observational studies reporting 25(OH)D concentrations in PAD patients and non-PAD participants. Data extraction and study quality assessments were conducted independently. A random-effects model was used to meta-analyse extracted data and generate standardized mean differences (SMDs) in circulating 25(OH)D levels between PAD patients and non-PAD controls. Subgroup analyses were conducted focussing on patients presenting with intermittent claudication (IC) and critical limb ischaemia (CLI).

RESULTS

Six case-control studies assessing 6418 individuals fulfilled the inclusion criteria. Two studies were considered to be of moderate methodological quality and four were considered to be of high quality. A meta-analysis of data from 1217 PAD patients and 5201 non-PAD participants showed that circulating 25(OH)D concentrations were lower in PAD patients compared with non-PAD participants (SMD = -0.32, 95% CI: -0.58, -0.05; P = 0.02). Subgroup analyses showed that 25(OH)D levels were significantly lower among PAD patients with CLI, but not IC, when compared to non-PAD controls (SMD = -1.29, 95% CI: -1.66, -0.91; P < 0.001 and SMD = -0.01, 95% CI: -0.15, 0.13; P=0.88, respectively).

CONCLUSIONS

This meta-analysis suggests that low levels of circulating 25(OH)D are associated with PAD presence, particularly in patients presenting with CLI. These data suggest the possibility that vitamin D insufficiency may contribute to the development of more advanced PAD although this remains to be confirmed.

Associations between calcium and vitamin D supplement use as well as their serum concentrations and subclinical cardiovascular disease phenotypes

BACKGROUND

Supplementation of calcium (Ca) and vitamin D for the prevention of osteoporosis is frequently found in Western countries. Recent re-analyses of clinical trials observed a higher risk of myocardial infarction and stroke in subjects taking Ca (+vitamin D) supplements, although the underlying mechanisms are not clear.

OBJECTIVE

Thus, we analyzed the associations between Ca and vitamin D supplementation as well as serum concentrations of Ca and 25-hydroxyvitamin D (25(OH)D) and subclinical cardiovascular disease (CVD) phenotypes, namely intima-media thickness, ankle-brachial-index (ABI), intermittent claudication, and atrial fibrillation (AF).

DESIGN

Data of 1601 participants aged 50-81 years of the population-based cross-sectional Cooperative Health Research in the Region of Augsburg (KORA) F4 study in Germany were analyzed. Logistic and linear regression models were used to estimate odds ratios (OR) (95% confidence intervals (CI)) and β-estimates (p-values), respectively.

RESULTS

Regular Ca supplementation showed a significant positive association with the presence of AF after multivariable adjustment (OR = 3.89; 95% CI 1.28-11.81). Higher serum 25(OH)D concentrations were independently associated with a lower prevalence of asymptomatic peripheral arterial disease as assessed by ABI measurements (β = 0.007; p = 0.01). No other significant associations between supplementation or serum concentrations of Ca or vitamin D and CVD phenotypes were identified.

CONCLUSIONS

Although based on few cases the finding of a significant higher prevalence of AF in Ca supplement users hints at one possible mechanism that may contribute to an increased risk of myocardial infarction and stroke. The observed association between serum 25(OH)D and ABI supports results from other studies.

Does sufficient evidence exist to support a causal association between vitamin D status and cardiovascular disease risk? An assessment using Hill's criteria for causality

Serum 25-hydroxyvitamin D (25(OH)D) levels have been found to be inversely associated with both prevalent and incident cardiovascular disease (CVD) risk factors; dyslipidemia, hypertension and diabetes mellitus. This review looks for evidence of a causal association between low 25(OH)D levels and increased CVD risk. We evaluated journal articles in light of Hill's criteria for causality in a biological system. The results of our assessment are as follows. Strength of association: many randomized controlled trials (RCTs), prospective and cross-sectional studies found statistically significant inverse associations between 25(OH)D levels and CVD risk factors. Consistency of observed association: most studies found statistically significant inverse associations between 25(OH)D levels and CVD risk factors in various populations, locations and circumstances. Temporality of association: many RCTs and prospective studies found statistically significant inverse associations between 25(OH)D levels and CVD risk factors. Biological gradient (dose-response curve): most studies assessing 25(OH)D levels and CVD risk found an inverse association exhibiting a linear biological gradient. Plausibility of biology: several plausible cellular-level causative mechanisms and biological pathways may lead from a low 25(OH)D level to increased risk for CVD with mediators, such as dyslipidemia, hypertension and diabetes mellitus. Experimental evidence: some well-designed RCTs found increased CVD risk factors with decreasing 25(OH)D levels. Analogy: the association between serum 25(OH)D levels and CVD risk is analogous to that between 25(OH)D levels and the risk of overall cancer, periodontal disease, multiple sclerosis and breast cancer.

CONCLUSION

all relevant Hill criteria for a causal association in a biological system are satisfied to indicate a low 25(OH)D level as a CVD risk factor.

Prognostic impact of arterial stiffness in patients with symptomatic peripheral arterial disease

OBJECTIVES

Arterial stiffness (AS) is increasingly recognized as an independent risk factor in different high-risk populations. Whether changes in AS can predict prognosis in patients with symptomatic peripheral arterial disease (PAD) has never been investigated. The aim of the present study was to test the hypothesis that AS is an independent predictor of all-cause and cardiovascular disease (CVD) mortality in patients with symptomatic PAD.

METHODS

A cohort of 117 symptomatic PAD patients (aged 62.3 ± 7.7 years) were prospectively recruited from the Department of Vascular Surgery, Tartu University Hospital, between 2002 and 2010. The AS was measured using pulse wave analysis and assessment of pulse wave velocity (PWV).

RESULTS

During the follow-up period (mean 4.1 ± 2.2 years) there were 32 fatal events. Kaplan-Meier analysis showed that the probability of all-cause and CVD mortality decreased with increasing small artery elasticity (SAE), as estimated by the log-rank test (p = .004; p = .005, respectively). By contrast, large artery elasticity, augmentation index, and aortic and brachial PWV were not significantly related to mortality. In a Cox proportional hazard model, SAE above the median was associated with decreased all-cause and CVD mortality after adjustment for confounding factors: relative risk (RR), 0.37; 95% confidence interval (CI), 0.17-0.81; p = .01; RR, 0.11; 95% CI, 0.01-0.86; p = .04, respectively).

CONCLUSIONS

This study provides the first evidence, obtained from an observational study, that decreased small artery elasticity is an independent predictor of all-cause and CVD mortality in patients with symptomatic PAD.

Adiposity and the relationship between vitamin D and blood pressure

OBJECTIVE

Circulating vitamin D (25OHD) concentrations are negatively associated with blood pressure (BP) but little is known about the mechanisms for this relationship. Adiposity is positively associated with BP and inversely with circulating 25OHD concentrations but no studies have assessed the relationship between plasma 25OHD and adiposity on BP. The goal of this study is to investigate if the association between plasma 25OHD and BP is mediated by adiposity.

MATERIALS/METHODS

The relationship between plasma 25OHD, systolic and diastolic BP, and adiposity [BMI, waist circumference, visceral adipose tissue (VAT)] was assessed in a multi-ethnic cross-sectional study of Aboriginal (n=151), Chinese (n=190), European (n=170), and South Asian (n=176) participants by linear regression models.

RESULTS

Plasma 25OHD concentrations were negatively associated with systolic (standardized B=-0.191, P<0.001) and diastolic BP (standardized B=-0.196, P<0.001) in models adjusted for age, sex, ethnicity, family history of CVD, smoking status, alcohol consumption, and physical activity. The negative relationship between plasma 25OHD concentrations and systolic and diastolic BP was attenuated after the addition of BMI, waist circumference, and VAT to the models, but the relationship remained significant. Plasma 25OHD concentrations accounted for 0.7% and 0.8% of the variance in systolic and diastolic BP, respectively.

CONCLUSION

These findings suggest that the relationship between vitamin D and BP is independent of adiposity. Further studies are required to determine the mechanisms by which vitamin D affects BP.

Vitamin D and cardiovascular disease: is the evidence solid?

Vitamin D deficiency, prevalent in 30-50% of adults in developed countries, is largely due to inadequate cutaneous production that results from decreased exposure to sunlight, and to a lesser degree from low dietary intake of vitamin D. Serum levels of 25-hydroxyvitamin D (25-OH D) <20 ng/mL indicate vitamin D deficiency and levels >30 ng/mL are considered optimal. While the endocrine functions of vitamin D related to bone metabolism and mineral ion homoeostasis have been extensively studied, robust epidemiological evidence also suggests a close association between vitamin D deficiency and cardiovascular morbidity and mortality. Experimental studies have demonstrated novel actions of vitamin D metabolites on cardiomyocytes, and endothelial and vascular smooth muscle cells. Low 25-OH D levels are associated with left ventricular hypertrophy, vascular dysfunction, and renin-angiotensin system activation. Despite a large body of experimental, cross-sectional, and prospective evidence implicating vitamin D deficiency in the pathogenesis of cardiovascular disease, a causal relationship remains to be established. Moreover, the cardiovascular benefits of normalizing 25-OH D levels in those without renal disease or hyperparathyroidism have not been established, and questions of an epiphenomenon where vitamin D status merely reflects a classic risk burden have been raised. Randomized trials of vitamin D replacement employing cardiovascular endpoints will provide much needed evidence for determining its role in cardiovascular protection.

Arterial Stiffness

Stiffness of large arteries has been long recognized as a significant determinant of pulse pressure. However, it is only in recent decades, with the accumulation of longitudinal data from large and varied epidemiological studies of morbidity and mortality associated with cardiovascular disease, that it has emerged as an independent predictor of cardiovascular risk. This has generated substantial interest in investigations related to intrinsic causative and associated factors responsible for the alteration of mechanical properties of the arterial wall, with the aim to uncover specific pathways that could be interrogated to prevent or reverse arterial stiffening. Much has been written on the haemodynamic relevance of arterial stiffness in terms of the quantification of pulsatile relationships of blood pressure and flow in conduit arteries. Indeed, much of this early work regarded blood vessels as passive elastic conduits, with the endothelial layer considered as an inactive lining of the lumen and as an interface to flowing blood. However, recent advances in molecular biology and increased technological sophistication for the detection of low concentrations of biochemical compounds have elucidated the highly important regulatory role of the endothelial cell affecting vascular function. These techniques have enabled research into the interaction of the underlying passive mechanical properties of the arterial wall with the active cellular and molecular processes that regulate the local environment of the load-bearing components. This review addresses these emerging concepts.

The association of 25(OH)D with blood pressure, pulse pressure and carotid-radial pulse wave velocity in African women

High susceptibility of the African population to develop cardiovascular disease obliges us to investigate possible contributing risk factors. Our aim was to determine whether low 25(OH)D status is associated with increased blood pressure and carotid-radial pulse wave velocity in black South African women. We studied 291 urban women (mean age: 57.56±9.00 yrs.). 25(OH)D status was determined by serum 25(OH)D levels. Women were stratified into sufficient (>30 ng/ml), and insufficient/deficient (<30 ng/ml) groups. Cardiovascular variables were compared between groups. Women with low 25(OH)D levels had significantly higher SBP (150.8±27.1 vs. 137.6±21.0), DBP (94.7±14.5 vs. 89.3±12.3) and PP (53.15(50.7;55.7) vs. 46.3(29.4;84.6)) compared to women with sufficient levels. No significant difference was observed with regards to c-rPWV. ANCOVA analyses still revealed significant differences between the two groups with regards to SBP, DBP as well as PP. Partial correlations revealed significant inverse association between SBP and 25(OH)D (p = .04;r = −.12). Women with low 25(OH)D levels were ∼2 times more likely to have high SBP (95% CI: 3.23;1.05). To conclude, women with deficient/insufficient 25(OH)D had significantly higher SBP compared to women with a sufficient 25(OH) status.

Vitamin D and hypertension: an update and review

PURPOSE OF REVIEW

Vitamin D deficiency and hypertension are highly prevalent. This review will discuss the association between vitamin D deficiency and blood pressure.

RECENT FINDINGS

During the past several years multiple prospective cohorts and randomized studies have been published. Recent studies have focused mostly on 25-hydroxy vitamin D, but a small number of trials used active vitamin D analog compounds.

SUMMARY

Data from cross-sectional studies report that low 25-hydroxy vitamin D is associated with higher systolic blood pressure and higher incidence of hypertension. Large observational studies show a weaker, yet similar association, but they have not largely accounted for the change in vitamin D levels over time. Randomized control trials conflict with observational data probably due to differences in populations studied, doses of vitamin D used, and unmeasured confounders. Further research is needed before clinical practice recommends vitamin D prescription as treatment for hypertension in the general population.

Hypovitaminosis D and peripheral arterial disease: emerging link beyond cardiovascular risk factors

Vitamin D has received increasing interest for its beneficial effect on health. Beyond its conventional role in bone metabolism, emerging evidence suggests a possible link between low vitamin D levels and cardiovascular disease (CVD), including peripheral arterial disease (PAD), and cardiovascular risk factors. Vitamin D interacts either directly with the vascular tree or indirectly through its association with cardiovascular risk factors, but the exact mechanism remains controversial. This review outlines the association between hypovitaminosis D and PAD. Both entities are quite prevalent in the general population and, therefore, their potential association might have important clinical implications. Whether vitamin D deficiency represents a novel risk factor for PAD/CVD, and whether vitamin D supplementation would reduce the burden of CVD still remains to be answered. Until then, vitamin D intake is not recommended for PAD/CVD prevention. Outdoor physical activity, coupled with adequate but safe sun exposure, is a healthy lifestyle practice suggested for the prevention of both PAD and hypovitaminosis D.

Vitamin D status and changes in cardiovascular risk factors: a prospective study of a general population

OBJECTIVES

A low vitamin D level has been associated with increased cardiovascular disease risk but possible mechanisms remain unclear. We investigated the association between vitamin D levels and 5-year changes in blood pressure, lipid profile and incidence of the metabolic syndrome, hypertension and hypercholesterolemia.

METHODS

A random sample of 6,784 individuals aged 30-60 years from a general population was investigated in the Inter99 study in 1999-2001. Vitamin D (serum 25-hydroxyvitamin D) was measured at baseline by high-performance liquid chromatography, and 4,330 individuals participated at the 5-year follow-up and were included in the present study.

RESULTS

The median baseline vitamin D concentration was 48.0 nmol/l. In multivariable linear regression analyses, a 10 nmol/l higher baseline level of vitamin D was associated with a decrease in triglycerides and very low density lipoprotein cholesterol by 0.52 (p = 0.03) and 0.66% (p = 0.005), respectively. In multivariable logistic regression analyses, the odds ratios per 10 nmol/l higher baseline vitamin D level were 0.95 (p < 0.05) and 0.94 (p = 0.01) for the development of the metabolic syndrome and hypercholesterolemia, respectively. There was no association between vitamin D and blood pressure.

CONCLUSIONS

An optimal vitamin D status may influence cardiovascular health by changing the lipid profile in a favorable direction and decreasing the incidence of the metabolic syndrome.

The role of nutrition and body composition in peripheral arterial disease

Peripheral arterial disease (PAD) has not been as extensively investigated as other cardiovascular diseases. However, the available data suggest that nutrition-based treatment strategies have the potential to reduce the cost-economic burden of PAD substantially. Abdominal obesity is associated with PAD and prospective and cross-sectional studies have shown that a low dietary intake of folate and reduced synthesis of vitamin D are associated with an increased risk of PAD and severe walking impairment in patients who have the disease. However, dietary patterns that are associated with decreased cardiovascular risk might protect against PAD. A small number of clinical trials have provided evidence that increased intakes of niacin and insoluble fiber might be associated with decreased levels of LDL cholesterol and thrombogenic biomarkers, as well as increased serum levels of HDL cholesterol in patients with PAD. However, little evidence that antioxidants, vitamins B(6) and B(12), or essential fatty acid supplements improve clinical outcomes in these patients exists. Overall, data on the effects of nutrition, body composition, and nutritional supplementation on the risk, progression, and prognosis of PAD are scarce. Further research into these areas is required to allow the development of evidence-based nutritional guidelines for the prevention and treatment of the disease.

Effect of a single, oral, high-dose vitamin D supplementation on endothelial function in patients with peripheral arterial disease: a randomised controlled pilot study

OBJECTIVE

Apart from its role in bone metabolism, vitamin D may also influence cardiovascular disease. The objective of this study was: (1) to determine the effect of a single, oral, high-dose vitamin D supplementation on endothelial function and arterial stiffness in patients with peripheral arterial disease (PAD) and (2) to investigate the impact of this supplementation on coagulation and inflammation parameters.

METHODS

In this double-blind, placebo-controlled, interventional pilot study, we screened 76 Caucasian patients with PAD for vitamin D deficiency. Sixty-two were randomised to receive a single, oral supplementation of 100,000 IU vitamin D3 or placebo. At baseline and after 1 month, we measured serum vitamin D and parathormone levels, and surrogate parameters for cardiovascular disease.

RESULTS

Sixty-five of 76 patients (86%) had low 25-hydroxyvitamin D levels (<30 ng ml(-1)); of those, 62 agreed to participate in the study. At baseline, only parathormone was related to vitamin D. In supplemented patients, vitamin D levels increased from 16.3 ± 6.7 to 24.3 ± 6.2 ng ml(-1) (P < 0.001), with wide variations between single patients; in the placebo group vitamin levels did not change. Seasonal factors accounted for a decrease of vitamin D levels by 8 ng ml(-1) between summer and winter. After 1 month, none of the measured parameters was influenced by vitamin substitution.

CONCLUSION

In this pilot study, most patients with PAD were vitamin D deficient. Vitamin D supplementation increased serum 25-hydroxyvitamin D without influencing endothelial function, arterial stiffness, coagulation and inflammation parameters, although the study was underpowered for definite conclusions.

Structural and biochemical characteristics of arterial stiffness in patients with atherosclerosis and in healthy subjects

Arterial stiffness is an independent predictor of vascular morbidity and mortality in patients with atherosclerosis. Angiographic score (ASc) reflects severity of atherosclerosis in patients with peripheral arterial disease (PAD). Osteopontin (OPN) and oxidized low-density lipoprotein (oxLDL) are involved in the pathogenesis of atherosclerosis. The aim of the present study was to evaluate the association between arterial stiffness, ASc, serum OPN and oxLDL in patients with symptomatic PAD, and in clinically healthy subjects. We studied 79 men with symptomatic PAD (mean age 64±7 years) and 84 healthy men (mean age 63±8 years). Calculation of the ASc was based on severity and location of atherosclerotic lesions in the arteries of the lower extremities. Aortic pulse wave velocity (aPWV) was evaluated by applanation tonometry using the Sphygmocor device. Serum OPN and oxLDL levels were determined by enzyme-linked immunosorbent assay. The aPWV (10±2.4 vs. 8.4±1.7 (m s(-1)); P<0.001), OPN (75 (62.3-85.8) vs. 54.8 (47.7-67.9) (ng ml(-1)); P<0.001) and oxLDL (67 (52.5-93.5) vs. 47.5 (37-65.5); P<0.001) were different for the patients and for the controls. In multiple regression models, aPWV was independently determined by ASc, log-OPN, log-oxLDL and estimated glomerular filtration rate in the patients (R2=0.44; P<0.001) and by log-OPN, log-oxLDL, age and heart rate in the controls (R2=0.38; P<0.001). The independent relationship of a PWV with serum levels of OPN and oxLDL in the patients with PAD and in the controls indicates that OPN and oxLDL might influence arterial stiffening in patients with atherosclerosis and in clinically healthy subjects.