Vitamin D and vascular calcification

Association of serum vitamin D with diagnosis and growth of abdominal aortic aneurysm

Objective

We examined the associations between 25-hydroxy vitamin D (25(OH)D3) concentration and the diagnosis and growth of abdominal aortic aneurysm (AAA).

Methods

AAA cases and healthy controls were recruited from vascular centers or the community. A subset of participants with AAA were monitored by repeat ultrasound examination to assess AAA growth. Serum 25(OH)D3 concentration was measured using a validated mass spectrometry method and categorized into guideline-recommended cut-points after deseasonalization. The associations between deseasonalized 25(OH)D3 concentration and AAA diagnosis and growth were examined using logistic regression and linear mixed effects modeling.

Results

A total of 4673 participants consisting of 873 (455 controls and 418 cases) from Queensland and 3800 (3588 controls and 212 cases) from Western Australia were recruited. For every 1 standard deviation increase in 25(OH)D3 concentration, odds of AAA diagnosis was significantly reduced in both Queensland (adjusted odds ratio: 0.81; 95% confidence interval [CI]: 0.69-0.95; P = .009) and Western Australia (adjusted odds ratio: 0.80; 95% CI: 0.68-0.94; P = .005) cohorts. A subset of 310 eligible participants with small AAA from both regions were followed for a median of 4.2 (interquartile range: 2.0-5.8) years. Compared with vitamin D sufficient participants (50 to ˂75 nmol/L), annual mean AAA growth was significantly greater in those with higher vitamin D (≥75 nmol/L) (adjusted mean difference: 0.1 mm/y, 95% CI: 0.1-0.2; P < .001).

Conclusions

High 25(OH)D3 concentration was paradoxically associated with a lower likelihood of AAA diagnosis and faster AAA growth. Further research is needed to resolve these conflicting findings.

Vitamin D and cardiovascular diseases: A narrative review

Cardiovascular diseases (CVD) and vitamin D deficiency are becoming highly prevalent among general populations. Despite plausible biological mechanisms for the role of vitamin D in cardio-protection, a cause-and-effect relationship has not yet been established. The interest in vitamin D as a potential therapeutic target to attenuate cardiovascular risk has been raised. The question about the benefit of vitamin D supplementation for cardiovascular outcomes cannot be answered certainly for the moment. The association between hypovitaminosis D and CVD has been proven by some studies while other studies deny any such link. The present narrative review gives a comprehensive overview of studies on the potential impact of hypovitaminosis D on CVD. The potential role of vitamin D supplementation in the management of CVD is also evaluated. Particular emphasis is paid to those studies that achieve a high level of scientific evidence.

Vitamin D and Cardiovascular Diseases: From Physiology to Pathophysiology and Outcomes

Vitamin D is rightly recognized as an essential key factor in the regulation of calcium and phosphate homeostasis, affecting primary adequate bone mineralization. In the last decades, a more complex and wider role of vitamin D has been postulated and demonstrated. Cardiovascular diseases have been found to be strongly related to vitamin D levels, especially to its deficiency. Pre-clinical studies have suggested a direct role of vitamin D in the regulation of several pathophysiological pathways, such as endothelial dysfunction and platelet aggregation; moreover, observational data have confirmed the relationship with different conditions, including coronary artery disease, heart failure, and hypertension. Despite the significant evidence available so far, most clinical trials have failed to prove any positive impact of vitamin D supplements on cardiovascular outcomes. This discrepancy indicates the need for further information and knowledge about vitamin D metabolism and its effect on the cardiovascular system, in order to identify those patients who would benefit from vitamin D supplementation.

Role of Vitamin D in Management of Diabetes and Unresolved Cardiovascular Diseases

BACKGROUND

Vitamin D deficiency is becoming a widely recognized global health issue. Serum values of 25-(OH) vitamin D (<20 ng/ml) are used to identify vitamin D deficiency. By prompting vascular endothelial cells to activate their nuclear receptor in cardio-myocytes, Vitamin D regulates obesity, Renin-angiotensin system (RAS), energy consumption, and pancreatic cell function. Vitamin D deficiency has been associated with diabetes, asthma, hyperlipidaemia, and pulmonary hypertension in humans.

METHODS

PubMed and Google Scholar databases were utilised to search the literature on vitamin D and related diseases.

RESULT

It is also linked to an elevated risk of death and heart disease. On the other hand, metaanalyses of vitamin D intervention and trials have found no substantial changes in insulin sensitivity, lipid markers, or blood pressure, which result in the association between deficiency of vitamin D and cardiovascular disease.

CONCLUSION

In this review, we present the most recent research on the effects of Vitamin D therapy on various cardiovascular diseases and diabetes, and explain the underlying mechanisms.

Vitamin D deficiency enhances vascular oxidative stress, inflammation, and angiotensin II levels in the microcirculation of diabetic patients

Low vitamin D (vitD) levels have been reported to be a risk factor for diabetes-related cardiovascular complications. This study examined the effects of vitD deficiency on oxidative stress (OS), inflammation, and levels of the vasoconstrictor angiotensin II (Ang II) in the microvascular tissue of type 2 diabetic patients. Patients were categorized into (i) vitD non-deficient diabetics (DNP, n = 10) and (ii) vitD-deficient diabetics (DDP, n = 10), based on their serum 25(OH)D levels. Subcutaneous fat tissues with intact blood vessels were collected during lower limb surgical procedures. The blood vessel were isolated; measurements of the antioxidant enzyme superoxide dismutase (SOD) activity, OS marker malondialdehyde (MDA), Ang II, and the inflammatory marker, TNF-α of the microvascular tissues were determined. Elevated MDA levels and reduced SOD activity, with higher levels of TNF-α and Ang II were observed in the microvascular tissues of DDP compared to DNP. VitD deficiency did not associate with glycemic parameters (fasting blood glucose and glycated hemoglobin) levels. In conclusion, vitD deficiency was correlated with higher microvascular tissue OS, inflammation, and Ang II levels in type 2 diabetic patients. This may contribute to early vasculopathy that occurs in diabetic patients, thus, may contribute to the planning of therapeutic strategies to delay or prevent cardiovascular complications.

Maternal vitamin D deficiency in early pregnancy and perinatal and long-term outcomes

Background

Vitamin D deficiency is common in pregnant women. Some studies have linked vitamin D deficiency to obstetric complications such as gestational hypertension, gestational diabetes, and preterm birth. Therefore, the objective of this study is to investigate the potential impact of vitamin D deficiency during pregnancy on both perinatal and long-term outcomes.

Methods

In this retrospective study, conducted between 2017 and 2021, we analyzed the data of 1079 singleton pregnant women with no medical or surgical complications prior to pregnancy. We evaluated obstetric and perinatal outcomes, as well as neurodevelopmental outcomes using Bayley-III tests, Gross Motor Function Measure, or chart review.

Results

The maternal serum vitamin D level in the first trimester was 18.2 ± 9.0 ng/mL. Vitamin D deficiency (<20 ng/mL) was found in 308 (62.0%) women in the first trimester, of which 288 women (26.7%) were in the very deficient group (<10 ng/mL). There were no differences in maternal age, body mass index, and previous preterm birth between the group with vitamin D < 10 ng/mL and ≥10 ng/mL group. There were also no differences in the rates of gestational hypertension, gestational diabetes, and preterm birth between the two groups, except for the rate of preterm birth before 37 weeks of gestation, which was significantly higher in the very deficient group (adjusted odds ratios [aOR] = 7.78, 95%CI [2.23-27.12], p = 0.001). In the very deficient group, the risk of developmental delay was also higher (aOR = 4.28, 95%CI [1.40-13.05], p = 0.011).

Conclusions

This is the first study to analyze the effects of maternal vitamin D deficiency during pregnancy on both long-term developmental outcomes and perinatal prognosis. Vitamin D deficiency, defined as a level lower than 10 ng/mL in the first trimester, may increase the risk of preterm birth and developmental delay in children.

Osteoporosis and cardiovascular disease: a review

BACKGROUND

Osteoporosis and cardiovascular disease are common diseases encountered globally, especially with advancing age. Osteoporosis occurs when there is a loss of bone mineral density leading to increased predisposition to fragility fracture. The conventional perception of osteoporosis is purely as a metabolic bone disease. However, there are mounting reports from recent studies that osteoporosis could be seen as a risk factor for cardiovascular disease just like other traditional risk factors such as hypertension, dyslipidaemia and diabetes. This is a paradigm shift with regards to the outlook of osteoporosis. Osteoporosis and cardiovascular disease have similar risk factors, including diabetes, smoking, excess alcohol, sedentary lifestyle, ageing and dyslipidaemia. This may partly explain the link between osteoporosis and cardiovascular disease. In addition, both osteoporosis and atherosclerosis, which underlies most cardiovascular disease, are both characterized by low grade chronic inflammation. Moreover, the processes involved in the calcification of atheroma are similar to what is seen in bone remodeling. Both processes also involve similar regulators such as osteoprotegerin and related proteins such as osteonectin, osteopontin and type 1 collagen are found in bone matrix and atheromatous plaques.

CONCLUSION

There is emerging evidence that individuals with osteoporosis are also at an increased risk of coronary artery disease and stroke even after controlling for other factors. The traditional risk factors for cardiovascular disease also predispose people to developing osteoporosis, suggesting that the same mechanism may be causing the two. Moreover, a number of anti-osteoporotic drugs have also been largely linked with cardiovascular disease. This calls for a change in the view of osteoporosis as a metabolic disease but as a cardio-metabolic disorder thereby emphasizing the need for intensified preventive strategies for the disease.

Updates in the chronic kidney disease-mineral bone disorder show the role of osteocytic proteins, a potential mechanism of the bone-Vascular paradox, a therapeutic target, and a biomarker

The chronic kidney disease-mineral bone disorder (CKD-MBD) is a complex multi-component syndrome occurring during kidney disease and its progression. Here, we update progress in the components of the syndrome, and synthesize recent investigations, which suggest a potential mechanism of the bone-vascular paradox. The discovery that calcified arteries in chronic kidney disease inhibit bone remodeling lead to the identification of factors produced by the vasculature that inhibit the skeleton, thus providing a potential explanation for the bone-vascular paradox. Among the factors produced by calcifying arteries, sclerostin secretion is especially enlightening. Sclerostin is a potent inhibitor of bone remodeling and an osteocyte specific protein. Its production by the vasculature in chronic kidney disease identifies the key role of vascular cell osteoblastic/osteocytic transdifferentiation in vascular calcification and renal osteodystrophy. Subsequent studies showing that inhibition of sclerostin activity by a monoclonal antibody improved bone remodeling as expected, but stimulated vascular calcification, demonstrate that vascular sclerostin functions to brake the Wnt stimulation of the calcification milieu. Thus, the target of therapy in the chronic kidney disease-mineral bone disorder is not inhibition of sclerostin function, which would intensify vascular calcification. Rather, decreasing sclerostin production by decreasing the vascular osteoblastic/osteocytic transdifferentiation is the goal. This might decrease vascular calcification, decrease vascular stiffness, decrease cardiac hypertrophy, decrease sclerostin production, reduce serum sclerostin and improve skeletal remodeling. Thus, the therapeutic target of the chronic kidney disease-mineral bone disorder may be vascular osteoblastic transdifferentiation, and sclerostin levels may be a useful biomarker for the diagnosis of the chronic kidney disease-mineral bone disorder and the progress of its therapy.

Association between Serum 25-Hydroxyvitamin D and Abdominal Aortic Calcification: A Large Cross-Sectional Study

In the American population, the relationship between the standardized serum 25-hydroxyvitamin D (25(OH)D) concentration and the risk of abdominal aortic calcification (AAC) is unclear. The purpose of our study was to investigate the relationship between serum 25(OH)D concentration and AAC risk. Participants from the National Health and Nutrition Examination Survey (NHANES) between 2013 and 2014 were analyzed cross sectionally. An analysis of the relationship between serum 25(OH)D concentration and incident AAC and severe AAC (SAAC) was based on the restricted cubic spline (RCS) and multivariable logistic regression model. In addition, generalized additive models with smooth functions were used to evaluate the relationship between serum 25(OH)D concentration and the degree of AAC. Finally, a subgroup analysis was conducted. There were a total of 3,040 individuals in our study. The serum 25(OH)D concentration was divided into quartiles (Q1: 9.37-50.5 nmol/L; Q2: 50.6-67.2 nmol/L; Q3: 67.3-85.8 nmol/L; and Q4: 85.9-318.0 nmol/L); the lowest quartile served as the reference group (Q1). After adjusting for known confounding variables, compared with the lowest quartile (Q1) of serum 25(OH)D concentration, the odds ratios with 95% confidence intervals for AAC and SAAC across the quartiles (Q2, Q3, and Q4) were (1.042 (0.812, 1.338), 0.863 (0.668, 1.115), and 1.022 (0.787, 1.327)) and (1.48 (0.87, 2.52), 1.70 (1.01, 2.92), and 2.13 (1.19, 3.86)), respectively. As shown by the RCS plot, the serum 25(OH)D concentration was associated with the risk of AAC/SAAC in a U-shaped pattern (P for nonlinearity <0.05). In addition, the degree of AAC decreased at first and then increased as the serum 25(OH)D concentration increased. In conclusion, a U-shaped relationship existed between serum 25(OH)D concentration and the risk of AAC and SAAC. Consequently, the risk of AAC and SAAC may be mitigated with regular monitoring and vitamin D supplementation.

Prediction of drug-induced liver injury and cardiotoxicity using chemical structure and in vitro assay data

Drug-induced liver injury (DILI) and cardiotoxicity (DICT) are major adverse effects triggered by many clinically important drugs. To provide an alternative to in vivo toxicity testing, the U.S. Tox21 consortium has screened a collection of ∼10K compounds, including drugs in clinical use, against >70 cell-based assays in a quantitative high-throughput screening (qHTS) format. In this study, we compiled reference compound lists for DILI and DICT and compared the potential of Tox21 assay data with chemical structure information in building prediction models for human in vivo hepatotoxicity and cardiotoxicity. Models were built with four different machine learning algorithms (e.g., Random Forest, Naïve Bayes, eXtreme Gradient Boosting, and Support Vector Machine) and model performance was evaluated by calculating the area under the receiver operating characteristic curve (AUC-ROC). Chemical structure-based models showed reasonable predictive power for DILI (best AUC-ROC = 0.75 ± 0.03) and DICT (best AUC-ROC = 0.83 ± 0.03), while Tox21 assay data alone only showed better than random performance. DILI and DICT prediction models built using a combination of assay data and chemical structure information did not have a positive impact on model performance. The suboptimal predictive performance of the assay data is likely due to insufficient coverage of an adequately predictive number of toxicity mechanisms. The Tox21 consortium is currently expanding coverage of biological response space with additional assays that probe toxicologically important targets and under-represented pathways that may improve the prediction of in vivo toxicity such as DILI and DICT.

The effect of combined magnesium and vitamin D supplementation on vitamin D status, systemic inflammation, and blood pressure: A randomized double-blinded controlled trial

OBJECTIVE

Poor vitamin D and magnesium status is observed in individuals who are overweight and obese (Owt/Ob) and is often associated with a heightened risk of cardiovascular disease. Magnesium is a cofactor that assists vitamin D metabolism. We aimed to determine the efficacy of a combined magnesium and vitamin D regimen compared with vitamin D only on increasing serum 25-hydroxyvitamin D (25OHD) concentrations and the effects of these supplements on cardiometabolic outcomes.

METHODS

This 12-week double-blinded randomized controlled trial had three treatment arms: magnesium + vitamin D (MagD; 360 mg magnesium glycinate + 1000 IU vitamin D 3 × daily), vitamin D only (VitD; 1000 IU vitamin D 3 × daily), and placebo. A total of 95 Owt/Ob participants were randomized into one of these three study arms. Anthropometry, dietary intake, concentrations of serum 25OHD, serum parathyroid hormone (PTH), serum inflammatory markers, and blood pressure were obtained at baseline and week 12.

RESULTS

The MagD group experienced the greatest increase in serum 25OHD concentrations (6.3 ± 8.36 ng/mL; P < 0.05). There was a decrease in systolic blood pressure (7.5 ± 8.26 mmHg; P < 0.05) for individuals who had a baseline systolic blood pressure of >132 mmHg in the MagD group. There were no statistically significant treatment effects on serum PTH concentrations and markers of inflammation.

CONCLUSIONS

A combined MagD treatment may be more effective in increasing serum 25OHD concentrations compared with VitD supplementation alone in Owt/Ob individuals.

Association Between Vitamin D Deficiency and Neurologic Outcomes in Patients After Cardiopulmonary Resuscitation

AIM

We investigated the association between vitamin D deficiency and neurologic outcomes after cardiopulmonary resuscitation.

METHOD

Data from the prospective cardiac arrest registry in the emergency department between October 2019 and April 2021 were retrospectively analyzed. Blood samples were obtained during cardiopulmonary resuscitation wherein 25-hydroxyvitamin D serum levels were analyzed; deficiency was defined as levels <10 ng/mL. The primary outcome was neurologic outcomes at 3 months assessed using the modified Rankin Scale.

RESULT

A total of 195 patients (mean age, 64.5 ± 16.1 years; 135 [69.2%] men) were included. A significantly greater proportion of patients with poor outcomes had vitamin D deficiency compared with those with good outcomes (49.4% vs. 18.2%, P = 0.001). The area under the curve for a sustained return of spontaneous circulation and 3-month poor neurologic outcomes was 0.595 (P = 0.031) and 0.704 (P < 0.001), respectively. In a multivariate analysis, vitamin D deficiency (odds ratio (OR): 10.22; 95% confidence interval (CI): 1.47-70.82, P = 0.019), initial shockable rhythm (OR: 0.03; 95% CI: 0.00-0.84, P = 0.040), low flow time (OR: 1.10; 95% CI: 1.03-1.16, P = 0.003), and thrombocytopenia (OR: 10.66; 95% CI: 1.13-100.41, P = 0.039) were significantly associated with 3-month poor neurologic outcomes.

CONCLUSION

The prevalence of vitamin D deficiency in patients with cardiac arrest was 44% and was associated with poor neurological outcomes at 3 months.

Vitamin D Supplementation Induces Cardiac Remodeling in Rats: Association with Thioredoxin-Interacting Protein and Thioredoxin

BACKGROUND

Vitamin D (VD) has been shown to play an important role in cardiac function. However, this vitamin exerts a biphasic "dose response" curve in cardiovascular pathophysiology and may cause deleterious effects, even in non-toxic doses. VD exerts its cellular functions by binding to VD receptor. Additionally, it was identified that the thioredoxin-interacting protein (TXNIP) expression is positively regulated by VD. TXNIP modulate different cell signaling pathways that may be important for cardiac remodeling.

OBJECTIVE

To evaluate whether VD supplementation lead to cardiac remodeling and if TXNIP and thioredoxin (Trx) proteins are associated with the process.

METHODS

A total of 250 Male Wistar rats were allocated into three groups: control (C, n=21), with no VD supplementation; VD3 (n = 22) and VD10 (n=21), supplemented with 3,000 and 10,000 IU of VD/ kg of chow respectively, for two months. The groups were compared by one-way analysis of variance (ANOVA) and Holm-Sidak post hoc analysis, (variables with normal distribution), or by Kruskal-Wallis test and Dunn's test post hoc analysis. The significance level for all tests was 5%.

RESULTS

TXNIP protein expression was higher and Trx activity was lower in VD10. The animals supplemented with VD showed increased lipid hydroperoxide and decreased superoxide dismutase and glutathione peroxidase. The protein Bcl-2 was lower in VD10. There was a decrease in fatty acid β-oxidation, tricarboxylic acid cycle and electron transport chain with shift to increase in glycolytic pathway.

CONCLUSION

VD supplementation led to cardiac remodeling and this process may be modulated by TXNIP and Trx proteins and consequently oxidative stress.

Non-Musculoskeletal Benefits of Vitamin D beyond the Musculoskeletal System

Vitamin D, a fat-soluble prohormone, is endogenously synthesized in response to sunlight or taken from dietary supplements. Since vitamin D receptors are present in most tissues and cells in the body, the mounting understanding of the role of vitamin D in humans indicates that it does not only play an important role in the musculoskeletal system, but has beneficial effects elsewhere as well. This review summarizes the metabolism of vitamin D, the research regarding the possible risk factors leading to vitamin D deficiency, and the relationships between vitamin D deficiency and numerous illnesses, including rickets, osteoporosis and osteomalacia, muscle weakness and falls, autoimmune disorders, infectious diseases, cardiovascular diseases (CVDs), cancers, and neurological disorders. The system-wide effects of vitamin D and the mechanisms of the diseases are also discussed. Although accumulating evidence supports associations of vitamin D deficiency with physical and mental disorders and beneficial effects of vitamin D with health maintenance and disease prevention, there continue to be controversies over the beneficial effects of vitamin D. Thus, more well-designed and statistically powered trials are required to enable the assessment of vitamin D’s role in optimizing health and preventing disease.

Calcitriol Supplementation Ameliorates Microvascular Endothelial Dysfunction in Vitamin D-Deficient Diabetic Rats by Upregulating the Vascular eNOS Protein Expression and Reducing Oxidative Stress

Diabetes mellitus contributes to macro- and microvascular complications, leading to adverse cardiovascular events. This study examined the effects of vitamin D deficiency on the vascular function and tissue oxidative status in the microcirculation of diabetic rats and to determine whether these effects can be reversed with calcitriol (active vitamin D metabolite) supplementation. Streptozotocin-induced diabetic rats were fed for 10 weeks with control diet (DC) or vitamin D-deficient diet without (DD) or with oral calcitriol supplementation (0.15 μg/kg) in the last four weeks (DDS) (10 rats each group). A nondiabetic rat group that received control diet was also included (NR). After 10 weeks, rats were sacrificed; mesenteric arterial rings with and without endothelium were studied using wire myograph. Western blotting of the mesenteric arterial tissue was performed to determine the protein expression of endothelial nitric oxide synthase (eNOS) enzyme. Antioxidant enzyme superoxide dismutase (SOD) activity and oxidative stress marker malondialdehyde (MDA) levels in the mesenteric arterial tissue were also measured. The DC group had significantly lower acetylcholine-induced relaxation and augmented endothelium-dependent contraction, with reduced eNOS expression, compared to NR rats. In mesenteric arteries of DD, acetylcholine-induced endothelium-dependent and sodium nitroprusside-induced endothelium-independent relaxations were lower than those in DC. Calcitriol supplementation in DDS restored endothelium-dependent relaxation. Mesenteric artery endothelium-dependent contraction of DD was greater than DC; it was not affected by calcitriol supplementation. The eNOS protein expression and SOD activity were significantly lower while MDA levels were greater in DD compared to DC; these effects were not observed in DDS that received calcitriol supplementation. In conclusion, vitamin D deficiency causes eNOS downregulation and oxidative stress, thereby impairing the vascular function and posing an additional risk for microvascular complications in diabetes. Calcitriol supplementation to diabetics with vitamin D deficiency could potentially be useful in the management of or as an adjunct to diabetes-related cardiovascular complications.

Vitamin D can be effective on the prevention of COVID-19 complications: A narrative review on molecular aspects

The widespread COVID-19 pandemic has been, currently, converted to a catastrophic human health challenge. Vitamin D (VD) and its metabolites have been used as a palliative treatment for chronic inflammatory and infectious diseases from ancient times. In the current study, some molecular aspects of the potential effects of VD against COVID-19 side-effects have been discussed. An arguable role in autophagy or apoptosis control has been suggested for VD through calcium signaling at the mitochondrial and ER levels. 1,25(OH)2D3 is also an immunomodulator that affects the development of B-cells, T-cells, and NK cells in both innate and acquired immunity. The production of some anti-microbial molecules such as defensins and cathelicidins is also stimulated by VD. The overexpression of glutathione, glutathione peroxidase, and superoxide dismutase, and down-regulation of NADPH oxidase are induced by VD to reduce the oxidative stress. Moreover, the multi-organ failure due to a cytokine storm induced by SARS-CoV2 in COVID-19 may be prevented by the immunomodulatory effects of VD. It can also downregulate the renin-angiotensin system which has a protective role against cardiovascular complications induced by COVID-19. Given the many experimental and molecular evidences due to the potential protective effects of VD on the prevention of the COVID-19-induced morbidities, a VD supplementation is suggested to prevent the lethal side-effects of the infection. It is particularly recommended in VD-deficient patients or those at greater risk of serious or critical effects of COVID-19, including the elderly, and patients with pre-existing chronic diseases, especially those in nursing homes, care facilities, and hospitals.

Vitamin D supplementation, cardiac events and stroke: A systematic review and meta-regression analysis

INTRODUCTION

Observational data has suggested a link between vitamin D deficiency and coronary heart disease (CHD). However, randomized controlled trials (RCTs) have failed to show benefit. The objective of this study is to analyze the RCTs investigating vitamin D supplementation and the risk of CHD and stroke.

METHODS

All RCTs that compared vitamin D supplementation to placebo and evaluated nonfatal myocardial infarction (MI), cardiac mortality, stroke and CHD events (a composite of cardiac mortality, MI, unstable angina and revascularization) were included. Rate ratios (RR) were calculated for each endpoint and to test for heterogeneity of treatment effect (HTE) the Chi2 and I2 tests were used for younger vs. older participants, shorter vs. longer trial duration, vitamin D supplements with vs. without calcium, and daily vs. monthly dosages of vitamin D. A meta-regression was performed with baseline vitamin D concentration as the covariate.

RESULTS

22 RCTs were identified (n = 83,200). Vitamin D supplementation had no effect on nonfatal MI (RR 0.98, 95% confidence interval (CI) 0.89-1.08), cardiac death (RR 0.94, CI 0.84-1.06), CHD events (RR 1.00, CI 0.91-1.10), or stroke (RR, 0.97, CI 0.9-1.03). When performing the meta-regression with baseline circulating 25-hydroxyvitamin D (25(OH)D) concentrations as the covariate, vitamin D supplementation's treatment effect on CVD outcomes was not associated with baseline 25(OH)D.

CONCLUSION

Vitamin D did not reduce CHD and stroke. A linear relationship does not exist between baseline 25(OH)D and vitamin D supplementation's effect on CVD. Vitamin D levels should be checked and repleted in those with an absolute indication.

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.

Serum vitamin D levels are associated with structural and functional properties of the carotid artery in older men and women

Aim

To investigate the possible relation between serum vitamin D levels and arterial structural and functional properties in older men and women.

Findings

Serum vitamin D levels are associated with carotid IMT and carotid stiffness. No assciation was found with brachial artery measurements.

Message

The associations between serum vitamin D levels and arterial parameters seems to be driven by the type of artery; only elastic arteries show this association.

Background and aims

This cross-sectional study aimed to assess the relationship between serum vitamin D levels and carotid and brachial artery distensibility in patients older than 55 years, referred to the outpatient clinic of the department of internal medicine and geriatric medicine of the Erasmus Medical Center, in Rotterdam.

Methods and results

From April to July 2006 we consecutively enrolled 49 elder patients (21 men and 28 women, mean age 78 ± 8 years) without a cardiovascular event within 6 weeks before the visit. Carotid and brachial artery distensibility coefficients and serum 25(OH)D levels (mean 50 ± 28.8 nmol/L) were assessed. Multivariate analysis (with linear regression model) was performed to investigate the relation between these parameters: carotid artery distensibility coefficient was associated with serum 25(OH)D levels (β = 0.112; 95% CI 0.053 0.172; p = 0.001). Moreover, a negative association was also observed between carotid artery distensibility coefficient and mean arterial pressure (β = −0.279; 95% CI, −0.339 −0.159; p = 0.0001). On the contrary, brachial artery distensibility has shown no association with 25(OH)D levels, being negatively linked to LDL-cholesterol levels and heart rate. An association was also observed between serum 25(OH)D level and carotid artery intima–media thickness.

Conclusion

Our results revealed that serum 25(OH)D levels of older men and women were associated with both structural and functional properties of the carotid artery. No association was found with the brachial artery distensibility.

Mineral Bone Abnormalities and Vascular Calcifications

Vascular calcification (VC) is common in chronic kidney disease, increases in prevalence as patients progress to end-stage renal disease, and is significantly associated with mortality. VC is a complex and highly regulated process similar to bone formation whereby hydroxyapatite crystals deposit in the intimal or medial layer of arteries. Mineral bone abnormalities are common in chronic kidney disease; reduction in glomerular filtration rate and changes in vitamin D, parathyroid hormone, and fibroblast growth factor 23 result in the dysregulation of phosphorus and calcium metabolism. Cell culture studies, animal models, and observational and clinical studies all suggest this abnormal mineral metabolism plays a role in the initiation and progression of VC in kidney disease. This review will focus on these mineral bone abnormalities and how they may contribute to mechanisms that induce VC in kidney disease.

Evaluation of the association of Wnt signaling with coronary artery calcification in patients on dialysis with severe secondary hyperparathyroidism

BACKGROUND

Patients with end-stage renal disease have a higher risk of death from cardiovascular events, which can be mainly attributed to coronary artery calcification (CAC). Wnt signaling is involved in vascular development and may play a role in vascular calcification. This study aimed to evaluate CAC prevalence in patients on dialysis with severe secondary hyperparathyroidism (SHPT) and identify CAC risk factors.

METHODS

The study is a retrospective analysis of the severe hyperparathyroidism registration study that prospectively recruited patients on dialysis with severe SHPT who were candidates for parathyroidectomy, from October 2013 to May 2015. CAC and bone mineral density (BMD) were measured. Demographic and clinical data including calcium, phosphorus, alkaline phosphatase, intact parathyroid hormone, Dickkopf-related protein 1 (DKK1), and sclerostin levels were analyzed. CAC scores were reported in Agatston units (AU).

RESULTS

A total of 61 patients were included in this study. No CAC, mild CAC (<100 AU), moderate CAC (>100 AU), and severe CAC (>400 AU) were observed in 4.9%, 11.4%, 14.8%, and 68.9% of patients, respectively. DKK1 and sclerostin were not associated with CAC. In univariate analysis, CAC was significantly correlated with age, sex (male), total cholesterol, and intravenous pulse calcitriol (p<0.05). CAC was not inversely correlated with the BMD, T scores, or Z scores of the femoral neck (p>0.05). In multivariate analysis, the stepwise forward multiple linear regression revealed that CAC was associated with age, male sex and intravenous pulse calcitriol (p<0.05). Furthermore, serum sclerostin was positively correlated with the BMD of the femoral neck but negatively associated with intact parathyroid hormone (p<0.05). Serum sclerostin was significantly associated with severely low bone mass with Z-scores<-2.5 of the femoral neck, even when adjusted for serum intact parathyroid hormone, vitamin D status, dialysis pattern, sex, and DKK-1 (p<0.05).

CONCLUSIONS

The patients on dialysis with severe SHPT have a high prevalence of vascular calcification. Although the Wnt signaling pathway could play a role in hyperparathyroid bone disease, CAC may be mainly due to the treatment modality rather than the Wnt signaling pathway associated bone metabolism in patients on dialysis with severe SHPT.

Low dietary magnesium intake alters vitamin D-parathyroid hormone relationship in adults who are overweight or obese

Vitamin D metabolism is dependent on magnesium (Mg) as a cofactor; therefore, poor Mg status may alter the relationship between vitamin D metabolite serum 25-hydroxyvitamin D (s25OHD) and serum parathyroid hormone (sPTH). We hypothesized that low dietary Mg intake may alter sPTH response to s25OHD in a population with excess body weight, thereby leading to a worsening of cardiometabolic health. To explore this hypothesis, we conducted a cross-sectional study on adults who were either overweight or obese (owt/ob). Dietary Mg intake was measured using a Mg food frequency questionnaire (MgFFQ). Body composition information was measured using Dual Energy X-ray Absorptiometry (DXA). Blood samples were obtained for all biochemical analyses. A total of 57 participants, 22 to 65 years of age, with a body mass index between 25 to 45 kg/m² were divided into 3 groups, according to dietary Mg intake percentiles (Low Mg Group = <33 percentile, Medium Mg Group = 33 to 66 percentile, High Mg Group = >66 percentile). Higher s25OHD was negatively associated with lower sPTH in the High Mg Intake group (r = -0.472, P = .041), but not in other groups. A positive relationship between s25OHD and serum high-molecular weight adiponectin concentrations was observed in the High Mg Group (r = 0.532, r = 0.022), but not in other groups. Serum Interleukin-6 concentrations were negatively associated with s25OHD (r = -0.316, P = .017) for the entire study group. Based on these results, our study demonstrated that a low dietary Mg intake may alter PTH response to 25OHD.

A New Light on Vitamin D in Obesity: A Novel Association with Trimethylamine-N-Oxide (TMAO)

Vitamin D deficiency and obesity are two public health problems extensively exacerbated over the last years. Among the several mechanisms proposed to account for the complex interplay between vitamin D and obesity, one that has gained particular attention is related to the emerging role of obesity-related changes in gut microbiota and gut-derived metabolites, such as Trimethylamine-N-oxide (TMAO). Vitamin D deficiency and high circulating TMAO levels are associated with body weight and the severity of non-alcoholic fatty liver disease (NAFLD). Considering the link of obesity with vitamin D on the one hand and obesity with TMAO on the other hand, and the central role of the liver in both the vitamin D and TMAO metabolism, the aim of this cross-sectional observational study was first, to confirm the possible inverse association between vitamin D and TMAO across different body mass index (BMI) classes and second, to investigate if this association could be influenced by the presence of NAFLD. One hundred and four adult subjects (50 males and 54 females; 35.38 ± 7.49 years) were enrolled. The fatty liver index (FLI) was used as a proxy for the diagnosis of NAFLD. Vitamin D deficiency was found in 65 participants (62.5%), while 33 subjects (31.7%) had insufficient levels, and the remaining subjects had sufficient levels of vitamin D. Subjects with both vitamin D deficiency and FLI-NAFLD had the highest TMAO levels (p < 0.001). By stratifying the sample population according to the BMI classes, vitamin D levels decreased significantly along with the increase of plasma TMAO concentrations, with the lowest vitamin D levels and highest TMAO, respectively, in class III obesity. Vitamin D levels showed significant opposite associations with circulating levels of TMAO (r = −0.588, p < 0.001), but this association was no longer significant after the adjustment for FLI values. The highest values of TMAO were significantly associated with the severity of obesity (OR 7.92; p < 0.001), deficiency of vitamin D (OR 1.62; p < 0.001), and FLI-NAFLD (OR 3.79; p < 0.001). The most sensitive and specific cut-off for vitamin D to predict the circulating levels of TMAO was ≤19.83 ng/mL (p < 0.001). In conclusion, our study suggests that high TMAO levels are associated with vitamin D deficiency and NAFLD. Further studies are required to investigate if there is a causality link or whether all of them are simply the consequence of obesity.

Questioning the Safety of Calcidiol in Hemodialysis Patients

Background. Epidemiological studies have suggested a survival benefit for hemodialysis patients on paricalcitol or calcitriol, but nutritional vitamin D supplementation of patients already on vitamin D receptor (VDR) activators is controversial. Methods. This observational retrospective cohort study was conducted with prospectively collected data from all consecutive patients with chronic kidney disease (CKD) who underwent hemodialysis under routine clinical practice conditions for two years. Results. Of the 129 patients, 89 were treated with calcidiol, paricalcitol, and/or calcitriol. The patients with any vitamin D formulation had higher serum concentrations of 25-hydroxy vitamin D and fibroblast growth factor-23 and tended to have higher mortality rates (42% vs. 25%, p = 0.07). On subgroup analysis, any calcidiol treatment or calcidiol combined with paricalcitol associated with significantly higher mortality rates than no treatment (47% and 62.5%, p = 0.043 and 0.008, respectively). The association between calcidiol/paricalcitol treatment and elevated mortality remained significant after adjusting for age, sex, diabetes, C-reactive protein, and hemodialysis vintage. Any calcidiol and calcidiol/paricalcitol treatment exhibited a dose-response relationship with mortality (p for trend: 0.002 and 0.005, respectively). Conclusions. These data draw attention to the hitherto unexplored safety of calcidiol supplementation in patients on hemodialysis, especially in those already on vitamin D. Until clinical trials demonstrate the safety and efficacy of this approach, caution should be exercised when prescribing these patients ≥0.5 calcidiol mg/month.

Are certain factors involved in calcium metabolism associated with temporomandibular disorders?

Objective: The aim of the present study was to investigate whether there is an association between serum concentrations of calcium, phosphate, alkaline phosphatase, parathyroid hormone (PTH), and vitamin D and temporomandibular disorders (TMDs).Methods: In this case-control study, 51 patients with TMDs (28 patients with TMJ clicking, 5 patients with muscular disorders, and 18 osteoarthritis patients) and 29 healthy subjects within the age range of 20-50 years as the control group, were referred to the laboratory for calcium, phosphate, alkaline phosphatase, PTH, and vitamin D (25 OHD) analysis tests. The TMJ status of all participants was examined according to RDC-TMD criteria by a prosthodontist who is an expert in TMDs. The results were analyzed with Fisher's precise test.Results: No statistically significant difference was observed between TMD patients and healthy subjects.Conclusion: Serum concentrations of calcium, phosphate, alkaline phosphatase, PTH, and vitamin D are not associated with TMDs.

Vitamin D in Cardiovascular Disease

Cardiovascular disease is the prevalent cause of morbidity and mortality in the world, affecting many millions of individuals every year. Atherosclerosis, a chronic inflammatory condition that involves different cell types, several cytokines and adhesion molecules, is the underlying cause of cardiovascular disease. Vitamin D is known to control skeletal patho/physiology, regulating calcium and phosphorus and bone remodeling along with other calcium-regulating hormones. However, several active metabolites of vitamin D can exert both direct action, mainly via vitamin D₃ receptor trans-activation and indirect actions on several other tissues by an endocrine, autocrine and paracrine manners. With regard to cardiovascular disease, vitamin D deficiency has been associated with activation of the pro-inflammatory mechanism, promoting atherogenesis. There are several large-scale clinical studies, as well as meta-analyses that support this finding. However, it is still unclear whether the plasma 25-hydroxyvitamin D level can be used as a biomarker for future cardiovascular disease. Herein we review the studies reporting a causative role for vitamin D in cardiovascular disease.

Vitamin D deficiency and electrocardiographic subclinical myocardial injury: Results from National Health and Nutrition Examination Survey-III

BACKGROUND

Association of cardiovascular disease (CVD) with nontraditional risk factors such as vitamin D deficiency has been examined previously. An investigation of the association of vitamin D with subclinical myocardial injury (SC-MI) based on an electrocardiographic score is a simple, cost-effective and innovative way to explore this relationship.

HYPOTHESIS

We hypothesize that low vitamin D levels will be associated with prevalent SC-MI independent of traditional CVD risk factors, lifestyle factors, and socioeconomic status.

METHODS

This analysis included 6079 participants (58.3 ± 13.1 years; 54.1% women) without CVD from the third National Health and Nutrition Examination Survey. A multivariable logistic regression model was used to examine the association between vitamin D categories (<20, 20-29, and >30 ng/mL (reference) and cardiac injury score.

RESULTS

There was an incremental increase in the prevalence of SC-MI across vitamin D categories with the highest prevalence in <20 ng/mL, followed by 20 to 29 ng/mL and then >30 ng/mL (trend P-value <0.0001). There was a statistically significant association between vitamin D deficiency (<20 ng/mL) and SC-MI (odds ratio [OR] (95% confidence interval [CI]): 1.27 (1.04-1.55), P = 0.04). This association was stronger in men than women (OR (95% CI): 1.74 (1.32-2.30) vs 0.94 (0.70-1.25) respectively; interaction P-value 0.002).

CONCLUSIONS

Vitamin D deficiency is associated with SC-MI, especially in men. These findings may further highlight the role of nontraditional risk factors in the development of CVD. The value of vitamin D supplementation in the prevention of myocardial ischemia and injury may warrant investigation.

Vitamin D Deficiency in Chronic Kidney Disease: Recent Evidence and Controversies

Vitamin D (VD) is a pro-hormone essential for life in higher animals. It is present in few types of foods and is produced endogenously in the skin by a photochemical reaction. The final step of VD activation occurs in the kidneys involving a second hydroxylation reaction to generate the biologically active metabolite 1,25(OH)₂-VD. Extrarenal 1α-hydroxylation has also been described to have an important role in autocrine and paracrine signaling. Vitamin D deficiency (VDD) has been in the spotlight as a major public healthcare issue with an estimated prevalence of more than a billion people worldwide. Among individuals with chronic kidney disease (CKD), VDD prevalence has been reported to be as high as 80%. Classically, VD plays a pivotal role in calcium and phosphorus homeostasis. Nevertheless, there is a growing body of evidence supporting the importance of VD in many vital non-skeletal biological processes such as endothelial function, renin-angiotensin-aldosterone system modulation, redox balance and innate and adaptive immunity. In individuals with CKD, VDD has been associated with albuminuria, faster progression of kidney disease and increased all-cause mortality. Recent guidelines support VD supplementation in CKD based on extrapolation from cohorts conducted in the general population. In this review, we discuss new insights on the multifactorial pathophysiology of VDD in CKD as well as how it may negatively modulate different organs and systems. We also critically review the latest evidence and controversies of VD monitoring and supplementation in CKD patients.

Vitamin D in Vascular Calcification: A Double-Edged Sword?

Vascular calcification (VC) as a manifestation of perturbed mineral balance, is associated with aging, diabetes and kidney dysfunction, as well as poorer patient outcomes. Due to the current limited understanding of the pathophysiology of vascular calcification, the development of effective preventative and therapeutic strategies remains a significant clinical challenge. Recent evidence suggests that traditional risk factors for cardiovascular disease, such as left ventricular hypertrophy and dyslipidaemia, fail to account for clinical observations of vascular calcification. Therefore, more complex underlying processes involving physiochemical changes to mineral balance, vascular remodelling and perturbed hormonal responses such as parathyroid hormone (PTH) and fibroblast growth factor 23 (FGF-23) are likely to contribute to VC. In particular, VC resulting from modifications to calcium, phosphate and vitamin D homeostasis has been recently elucidated. Notably, deregulation of vitamin D metabolism, dietary calcium intake and renal mineral handling are associated with imbalances in systemic calcium and phosphate levels and endothelial cell dysfunction, which can modulate both bone and soft tissue calcification. This review addresses the current understanding of VC pathophysiology, with a focus on the pathogenic role of vitamin D that has provided new insights into the mechanisms of VC.

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.

Relation of Serum Vitamin D to Risk of Mitral Annular and Aortic Valve Calcium (from the Multi-Ethnic Study of Atherosclerosis)

Serum 25-hydroxyvitamin D [25(OH)D] concentration has been identified as a possible modifiable risk factor for cardiovascular disease (CVD). We hypothesized that serum 25(OH)D concentration would be associated with calcifications of the left-sided heart valves, which are markers of CVD risk. Aortic valve calcium (AVC) and mitral annular calcium (MAC) were quantified from cardiac computed tomography scans performed on 5,530 Multi-Ethnic Study of Atherosclerosis participants at the baseline examination (2000 to 2002) and at a follow-up visit at either Examination 2 (2002 to 2004) or Examination 3 (2004 to 2005). 25(OH)D was measured from serum samples collected at the baseline examination. Using relative risk regression, we evaluated the multivariable-adjusted risk of prevalent and incident AVC and MAC in this ethnically diverse population free of clinical CVD at baseline. The mean age of participants was 62 ± 10 years; 53% were women, 40% white, 26% black, 21% Hispanic, and 12% Chinese. Prevalent AVC and MAC were observed in 12% and 9% of study sample, respectively. There were no significant associations between 25(OH)D and prevalent AVC or MAC. Over a mean follow-up of 2.5 years, 4% developed incident AVC and 5% developed incident MAC. After adjusting for demographic variables, each 10 ng/ml higher serum 25(OH)D was associated with a 15% (relative risk 0.85, 95% confidence interval 0.74 to 0.98) lower risk of incident MAC but not AVC. However, this association was no longer significant after adjusting for lifestyle and CVD risk factors. Results suggest a possible link between serum 25(OH)D and the risk for incident MAC, but future studies with longer follow-up are needed to further test this association.

High phosphate induces a pro-inflammatory response by vascular smooth muscle cells and modulation by vitamin D derivatives

In chronic kidney disease patients, high phosphate (HP) levels are associated with cardiovascular disease, the major cause of morbidity and mortality. Since serum phosphate has been independently correlated with inflammation, the present study aimed to investigate an independent direct effect of HP as a pro-inflammatory factor in VSMCs. A possible modulatory effect of vitamin D (VitD) was also investigated. The study was performed in an in vitro model of human aortic smooth muscle cells (HASMCs). Incubation of cells in an HP (3.3 mM) medium caused an increased expression of the pro-inflammatory mediators intercellular adhesion molecule 1 (ICAM-1), interleukins (ILs) IL-1β, IL-6, IL-8 and tumour necrosis factor α (TNF-α) (not corroborated at the protein levels for ICAM-1), as well as an increase in reactive oxygen/nitrogen species (ROS/RNS) production. This was accompanied by the activation of nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) signalling as demonstrated by the increase in the nuclear translocation of nuclear factor κ-light-chain-enhancer of activated B cells protein 65 (p65-NF-κΒ) assessed by Western blotting and confocal microscopy. Since all these events were attenuated by an antioxidant pre-incubation with the radical scavenger Mn(III)tetrakis (4-benzoic acid) porphyrin (MnTBAP), it is suggested that the inflammatory response is upstream mediated by the ROS/RNS-induced activation of NF-κΒ. Addition of paricalcitol (PC) 3·10−8 M to cells in HP prevented the phosphate induced ROS/RNS increase, the activation of NF-κΒ and the cytokine up-regulation. A bimodal effect was observed, however, for different calcitriol (CTR) concentrations, 10−10 and 10−12 M attenuated but 10−8 M stimulated this phosphate induced pro-oxidative and pro-inflammatory response. Therefore, these findings provide novel mechanisms whereby HP may directly favour vascular dysfunctions and new insights into the protective effects exerted by VitD derivatives.

Does Vitamin D Deficiency Effect Heart Rate Variability in Low Cardiovascular Risk Population?

AIM:

This study aimed to evaluate the cardiac autonomic dysfunction and the cardiac arrhythmia risk using heart rate variability parameters in subjects with vitamin D deficiency and low cardiovascular risk.

MATERIAL AND METHODS:

One hundred five consecutive individuals, 54 patients with low vitamin D status and 51 healthy controls were enrolled in this study. The overall cardiac autonomic tone was quantified by using various heart rate variability parameters included mean RR interval, mean Heart Rate, mean of standard deviations of intervals for 24 hours (SDNN), standard deviation of averages of intervals (SDANN), mean of standard deviation of intervals for 5 minutes (SDNNI), root mean square of difference of successive intervals (rMSSD) and the proportion of intervals differing more than 50 ms (pNN50) values. The 12-lead ECG was recorded from each participant, and QT intervals were measured.

RESULTS:

Baseline demographic profiles were similar between two groups. The heart rate variability parameters such as mean RR interval, mean HR, SDNN, SDANN, SDNNI, rMSSD and pNN50 (%) values were not significantly different in patients with low vitamin D status compared to control group. The electrocardiography analysis revealed only slight but significant prolongation of corrected QT (QTc) intervals in the control group.

CONCLUSION:

HRV variables were not significantly altered in patients with vitamin D deficiency in low cardiovascular risk profile group. Further studies evaluating these findings in other cohorts with high cardiovascular risk are required.

Vitamin D deficiency/insufficiency from childhood to adulthood: Insights from a sunny country

Vitamin D is known to be a key regulator of bone metabolism and is associated with muscle strength. Vitamin D deficiency is widely prevalent worldwide. In adults, vitamin D deficiency has been implicated in numerous health conditions including osteoporosis, cancer, diabetes, and autoimmune diseases. Considerable changes have occurred in lifestyles and childhood activities in the past years. Studies have shown that the children population is at high risks of vitamin D deficiency. The objective of this study was to learn about the extent of vitamin D deficiency in children worldwide and especially in sunny country like Israel. In this article we reviewed the extent and severity of vitamin D deficiency worldwide and especially in Israel, through a very comprehensive review of previous reports and research studies done during the last years. We found reports on vitamin D deficiency in children, which was associated with metabolic syndromes and obesity. It was more prevalent in children who spend less time on outdoor activities, in obese children, and in cases when there was imbalance between nutritional intakes and requirements. Vitamin D deficiency is common even in children living in sunny places like Israel. Health professionals should be aware of the fact that although vitamin D deficiency is prevalent in the elderly population, it is also common in children, and can be associated with different illnesses. We encourage supplementation of vitamin D to special populations (pregnant and lactating women, infants, and high risk groups). We also encourage implementation of international food fortification programs.

Role of Vitamin D in the Outcome of Ischemic Stroke- A Randomized Controlled Trial

INTRODUCTION

Vitamin D deficiency has reached epidemic proportions in India with prevalence rates of 70-100% in the general population. Low vitamin D levels are associated with worse outcomes in ischemic strokes. The outcome of stroke after vitamin D replenishment has not been much studied.

AIM

To compare the stroke outcome between patients receiving vitamin D supplementation and patients without vitamin D supplementation by Scandinavian Stroke Scale (SSS) and thus, to assess the long term outcome of ischemic stroke patients with low vitamin D level by supplementation of vitamin D.

MATERIALS AND METHODS

This is a non blinded randomized controlled trial conducted in ischemic stroke patients. The patients were divided into two groups (A and B) where Group A received a single dose of 6 lac IU of Cholecalciferol Intramascular (IM) injection and Group B were not given vitamin D. Finally 30 patients in each group were analyzed. SSS was applied to evaluate the stroke severity at the onset and at the follow up after three months in both groups. The difference in SSS was analyzed using SPSS software. Independent t-test was applied and p-value < 0.05 was taken as significant.

RESULTS

Mean±SD of vitamin D levels in Group A and Group B were 17.98±3.81ng/ml and 18.44±4.69 ng/ml respectively. Mean±SD of SSS at time of admission and after three months for Group A was 32.50±11.61 and 38.89±8.34; and for Group B 35.82±8.56 and 38.32±7.10. The difference in SSS from time of admission and after three months, in Group A (6.39±4.56) and Group B (2.50±2.20) were analyzed statistically and found to be highly significant (p<0.001).

CONCLUSION

The results showed that there is a significant improvement in the stroke outcome after three months in those patients who were supplemented with vitamin D. Thus screening for vitamin D deficiency in stroke patients is essential and vitamin D replenishment will improve the stroke outcome.

The Biphasic Effect of Vitamin D on the Musculoskeletal and Cardiovascular System

This narrative review summarizes beneficial and harmful vitamin D effects on the musculoskeletal and cardiovascular system. Special attention is paid to the dose-response relationship of vitamin D with clinical outcomes. In infants and adults, the risk of musculoskeletal diseases is highest at circulating 25-hydroxyvitamin D (25OHD) concentrations below 25 nmol/L and is low if 40-60 nmol/L are achieved. However, evidence is also accumulating that in elderly people the risk of falls and fractures increases again at circulating 25OHD levels > 100 nmol/L. Cohort studies report a progressive increase in cardiovascular disease (CVD) events at 25OHD levels < 50 nmol/L. Nevertheless, meta-analyses of randomized controlled trials suggest only small beneficial effects of vitamin D supplements on surrogate parameters of CVD risk and no reduction in CVD events. Evidence is accumulating for adverse vitamin D effects on CVD outcomes at 25OHD levels > 100 nmol/L, but the threshold may be influenced by the level of physical activity. In conclusion, dose-response relationships indicate deleterious effects on the musculoskeletal system and probably on the cardiovascular system at circulating 25OHD levels < 40-60 nmol/L and >100 nmol/L. Future studies should focus on populations with 25OHD levels < 40 nmol/L and should avoid vitamin D doses achieving 25OHD levels > 100 nmol/L.

Association between serum 25-hydroxyvitamin D levels and carotid atherosclerosis in chronic kidney disease patients

Background

Epidemiological studies have shown an inverse relationship between vitamin D levels and cardiovascular diseases. However, this does not infer a causal relationship between the two. Chronic kidney disease (CKD) patients have a high prevalence of vitamin D deficiency and carotid atherosclerosis. Therefore, in this study we have aimed to determine the association between serum 25-hydroxyvitamin D levels and carotid atherosclerosis in the CKD population.

Methods

100 CKD stage 3–4 patients were included in the study. Direct chemiluminesent immunoassay was used to determine the level of serum 25-hydroxyvitamin D. All subjects underwent a carotid ultrasound to measure common carotid artery intima-media thickness (CCA-IMT) and to assess the presence of carotid plaques or significant stenosis (≥50 %). Vitamin D deficiency was defined as serum 25-hydroxyvitamin D < 25 nmol/L. Abnormal CCA-IMT was defined as CCA-IMT ≥ 0.8 mm. Plaque was defined as a focal structure that encroaches into the arterial lumen of ≥ 0.5 mm or 50 % of the surrounding IMT value. Significant stenosis was defined as peak-systolic velocities ≥ 125 cm/s and end-diastolic velocities ≥ 40 cm/s.

Results

The vitamin D deficiency and non-deficiency groups did not differ significantly in terms of abnormal CCA-IMT (P = 0.443), carotid plaque (P = 0.349), and carotid stenosis (P = 0.554). No significant correlation between serum 25-hydroxyvitamin D levels and CCA-IMT (P = 0.693) was found. On a backward multiple linear regression model, serum 25-hydroxyvitamin D levels was not associated with CCA-IMT, abnormal CCA-IMT, or plaque presence.

Conclusions

No important association between serum 25-hydroxyvitamin levels and carotid atherosclerosis was found in CKD patients.

Low serum intact parathyroid hormone level is an independent risk factor for overall mortality and major adverse cardiac and cerebrovascular events in incident dialysis patients

Abnormal bone dynamics is a major risk factor for cardiovascular disease in patients with chronic kidney disease. The level of serum intact parathyroid hormone (iPTH) is widely used as a bone dynamic marker. We investigated the effect of the mean level of serum iPTH on overall mortality and cardiovascular outcomes in incident dialysis patients.

PURPOSE

Chronic kidney disease-mineral bone disorder (CKD-MBD) is a major risk factor for cardiovascular disease (CVD) in patients with end-stage renal disease (ESRD). CKD-MBD is classified as low- or high-turnover bone disease according to the bone dynamics; both are related to vascular calcification in ESRD. To evaluate the prognostic value of abnormal serum parathyroid hormone (PTH) levels on ESRD patients, we investigated the effects of time-averaged serum intact PTH (TA-iPTH) levels on overall mortality and major adverse cardiac and cerebrovascular events (MACCEs) in incident dialysis patients.

METHODS

Four hundred thirteen patients who started dialysis between January 2009 and September 2013 at Yonsei University Health System were enrolled. The patients were divided into three groups according to TA-iPTH levels during the 12 months after the initiation of dialysis: group 1, <65 pg/ml; group 2, 65-300 pg/ml; and group 3, >300 pg/ml. Cox regression analyses were performed to determine the prognostic value of TA-iPTH for overall mortality and MACCEs.

RESULTS

The mean age of the patients was 57 ± 15 years, and 222 patients (54 %) were men. During the median follow-up of 40.8 ± 29.3 months, 49 patients (12 %) died, and MACCEs occurred in 55 patients (13 %). The multivariate Cox regression analyses demonstrated that a low TA-iPTH level was an independent risk factor for both overall mortality (group 2 as reference; group 1: hazard ratio (HR) = 2.06, 95 % confidence interval (CI) = 1.11-3.83, P = 0.023) and MACCEs (HR = 1.82, 95 % CI = 1.04-3.20, P = 0.036) in incident dialysis patients after adjustment for confounding factors.

CONCLUSION

Low serum TA-iPTH is a useful clinical marker of both overall mortality and MACCEs in patients undergoing incident dialysis, mediated by vascular calcification.

Vitamin-D receptor agonist calcitriol reduces calcification in vitro through selective upregulation of SLC20A2 but not SLC20A1 or XPR1

Vitamin D deficiency (hypovitaminosis D) causes osteomalacia and poor long bone mineralization. In apparent contrast, hypovitaminosis D has been reported in patients with primary brain calcifications (“Fahr’s disease”). We evaluated the expression of two phosphate transporters which we have found to be associated with primary brain calcification (SLC20A2, whose promoter has a predicted vitamin D receptor binding site, and XPR1), and one unassociated (SLC20A1), in an in vitro model of calcification. Expression of all three genes was significantly decreased in calcifying human bone osteosarcoma (SaOs-2) cells. Further, we confirmed that vitamin D (calcitriol) reduced calcification as measured by Alizarin Red staining. Cells incubated with calcitriol under calcifying conditions specifically maintained expression of the phosphate transporter SLC20A2 at higher levels relative to controls, by RT-qPCR. Neither SLC20A1 nor XPR1 were affected by calcitriol treatment and remained suppressed. Critically, knockdown of SLC20A2 gene and protein with CRISPR technology in SaOs2 cells significantly ablated vitamin D mediated inhibition of calcification. This study elucidates the mechanistic importance of SLC20A2 in suppressing the calcification process. It also suggests that vitamin D might be used to regulate SLC20A2 gene expression, as well as reduce brain calcification which occurs in Fahr’s disease and normal aging.

Vitamin D and Diabetic Complications: True or False Prophet?

Vitamin D deficiency is now recognized as a condition of increasing prevalence worldwide. Vitamin D has an established role in calcium and bone metabolism; however, more recently associations with vitamin D deficiency and risk of developing diabetes, diabetes complications, and cardiovascular disease have all been acknowledged. The vitamin D receptor is ubiquitously expressed, and experimental, in vitro, and in vivo studies strongly suggest a role in regulating the transcription of multiple genes beyond calcium homeostasis. These include antiproliferative, immunomodulatory, angiogenic, inhibition of the renin-angiotensin-aldosterone system, and neurotrophic factor expression. Observational studies report a strong association between vitamin D deficiency and cardiovascular and metabolic disorders; however, there remains a paucity of large long-term randomized clinical trials showing a benefit with treatment. An increasing body of literature suggests a possible pathogenetic role of vitamin D in the long-term complications of diabetes and vitamin D deficiency may also exacerbate symptoms of painful diabetic peripheral neuropathy. It remains unknown if supplementation of vitamin D to normal or non-deficient levels alters pathogenetic processes related to diabetic microvascular complications. With the high prevalence of vitamin D deficiency in patients with diabetes and putative mechanisms linking vitamin D deficiency to diabetic complications, there is a compelling argument for undertaking large well-designed randomized controlled trials of vitamin D supplementation.

Biomarkers Associated with Vascular Calcification in Peritoneal Dialysis

♦

BACKGROUND

Vascular calcification is strongly associated with cardiovascular disease and mortality. However, some factors related to vascular calcification in patients with end-stage renal disease receiving peritoneal dialysis (PD) remain unknown. This study aimed to evaluate the associations of osteoprotegerin (OPG), osteopontin (OPN), osteocalcin (OCN), fibroblast growth factor 23 (FGF-23), magnesium, and phosphate clearance with vascular calcification in PD subjects, assessed by plain radiographs. ♦

METHODS

Simple vascular calcification scores (SVCS) obtained from plain X-rays of the pelvis and hands, and the Kauppila Index (KI) from lateral lumbar X-rays were assessed in 76 adults receiving PD for ≥ 6 months (43 women, median age 39 years, median time on PD 1.4 years). Levels of OPG, OPN, OCN, and FGF-23 were determined by luminometry. ♦

RESULTS

Serum OPG levels were higher in subjects with vascular calcification (n = 22 with SVCS > 3; n = 19 with KI > 7) compared with those with less calcification (p < 0.001). Spearman's correlation coefficients between OPG and SVCS and KI were r = 0.49 and r = 0.51, respectively (both p < 0.001). Subjects with vascular calcification had significantly lower renal phosphate clearance. Multiple regression analysis showed that vascular calcification assessed by SVCS was associated with age (r = 0.2, p = 0.042), diabetes mellitus (r = 2.4, p < 0.001), body mass index (BMI) (r = 0.09, p = 0.037), and OPG (r = 0.22, p = 0.001). Vascular calcification assessed by KI was associated with age (r = 0.16, p < 0.001), time on PD (r = 0.54, p = 0.001) and OPG (r = 0.08, p = 0.04). Osteocalcin, OPN, FGF-23, and magnesium were not associated with vascular calcification. ♦

CONCLUSIONS

Higher levels of OPG were consistently associated with vascular calcification in subjects on PD.

Vitamin D and atherosclerosis

PURPOSE OF REVIEW

To provide an overview of the association between vitamin D deficiency and atherosclerosis.

RECENT FINDINGS

Vitamin D exerts protective effects on atherosclerosis through multiple mechanisms. It has been shown to protect against endothelial dysfunction, vascular smooth muscle cell proliferation and migration, and modulation of the immune system, as well as the inflammatory response. In addition, vitamin D has been shown to have systemic effects on insulin resistance, dyslipidemia, and hypertension.

SUMMARY

Vitamin D deficiency is widely prevalent in the United States and worldwide. Although deficiency of this fat-soluble vitamin is usually associated with musculoskeletal disorder, it is associated with a wide range of disease processes that include multiple organ systems. Recently, there has been mounting evidence linking vitamin D deficiency to cardiovascular disease and atherosclerosis.

Vitamin D plasma levels and in-hospital and 1-year outcomes in acute coronary syndromes: a prospective study

Deficiency in 25-hydroxyvitamin D (25[OH]D), the main circulating form of vitamin D in blood, could be involved in the pathogenesis of acute coronary syndromes (ACS). To date, however, the possible prognostic relevance of 25 (OH)D deficiency in ACS patients remains poorly defined. The purpose of this prospective study was to assess the association between 25 (OH)D levels, at hospital admission, with in-hospital and 1-year morbidity and mortality in an unselected cohort of ACS patients.We measured 25 (OH)D in 814 ACS patients at hospital presentation. Vitamin D serum levels >30 ng/mL were considered as normal; levels between 29 and 21 ng/mL were classified as insufficiency, and levels < 20 ng/mL as deficiency. In-hospital and 1-year outcomes were evaluated according to 25 (OH)D level quartiles, using the lowest quartile as a reference.Ninety-three (11%) patients had normal 25 (OH)D levels, whereas 155 (19%) and 566 (70%) had vitamin D insufficiency and deficiency, respectively. The median 25 (OH)D level was similar in ST-elevation myocardial infarction (STEMI) and non-ST-elevation myocardial infarction (NSTEMI) patients (14.1 [IQR 9.0-21.9] ng/mL and 14.05 [IQR 9.1-22.05] ng/mL, respectively; P = .88). The lowest quartile of 25 (OH)D was associated with a higher risk for several in-hospital complications, including mortality. At a median follow-up of 366 (IQR 364-379) days, the lowest quartile of 25 (OH)D, after adjustment for the main confounding factors, remained significantly associated to 1-year mortality (P < .01). Similar results were obtained when STEMI and NSTEMI patients were considered separately.In ACS patients, severe vitamin D deficiency is independently associated with poor in-hospital and 1-year outcomes. Whether low vitamin D levels represent a risk marker or a risk factor in ACS remains to be elucidated.