Vitamin D deficiency and risk of cardiovascular disease

Uptake of Vitamins D2, D3, D4, D5, D6, and D7 Solubilized in Mixed Micelles by Human Intestinal Cells, Caco-2, an Enhancing Effect of Lysophosphatidylcholine on the Cellular Uptake, and Estimation of Vitamins D' Biological Activities

Vitamins D have various biological activities, as well as intestinal calcium absorption. There has been recent concern about insufficient vitamin D intake. In addition to vitamins D₂ and D₃, there are lesser-known vitamins D₄–D₇. We synthesized vitamins D₅–D₇, which are not commercially available, and then evaluated and compared the mixed micelles-solubilized vitamins D uptake by Caco-2 cells. Except for vitamin D₅, the uptake amounts of vitamins D₄–D₇ by differentiated Caco-2 cells were similar to those of vitamins D₂ and D₃. The facilitative diffusion rate in the ezetimibe inhibited pathway was approximately 20% for each vitamin D type, suggesting that they would pass through the pathway at a similar rate. Lysophosphatidylcholine enhanced each vitamin D uptake by approximately 2.5-fold. Lysophosphatidylcholine showed an enhancing effect on vitamin D uptake by reducing the intercellular barrier formation of Caco-2 cells by reducing cellular cholesterol, suggesting that increasing the uptakes of vitamins D and/or co-ingesting them with lysophosphatidylcholine, would improve vitamin D insufficiency. The various biological activities in the activated form of vitamins D₄–D₇ were estimated by Prediction of Activity Spectra for Substances (PASS) online simulation. These may have some biological activities, supporting the potential as nutritional components.

Mismatch: a comparative study of vitamin D status in British-Bangladeshi migrants

Background and objectives

Low levels of vitamin D among dark-skinned migrants to northern latitudes and increased risks for associated pathologies illustrate an evolutionary mismatch between an environment of high ultraviolet (UV) radiation to which such migrants are adapted and the low UV environment to which they migrate. Recently, low levels of vitamin D have also been associated with higher risks for contracting COVID-19. South Asians in the UK have higher risk for low vitamin D levels. In this study, we assessed vitamin D status of British-Bangladeshi migrants compared with white British residents and Bangladeshis still living in Bangladesh (‘sedentees’).

Methodology

The cross-sectional study compared serum vitamin D levels among 149 women aged 35–59, comprising British-Bangladeshi migrants (n = 50), white British neighbors (n = 54) and Bangladeshi sedentees (n = 45). Analyses comprised multivariate models to assess serum levels of 25-hydroxyvitamin D (25(OH)D), and associations with anthropometric, lifestyle, health and migration factors.

Results

Vitamin D levels in Bangladeshi migrants were very low: mean 25(OH)D = 32.2 nmol/L ± 13.0, with 29% of migrants classified as deficient (<25 nmol/L) and 94% deficient or insufficient (≤50 nmol/L). Mean levels of vitamin D were significantly lower among British-Bangladeshis compared with Bangladeshi sedentees (50.9 nmol/L ± 13.3, P < 0.001) and were also lower than in white British women (55.3 nmol/L ± 20.9). Lower levels of vitamin D were associated with increased body mass index and low iron status.

Conclusions and implications

We conclude that lower exposure to sunlight in the UK reduces vitamin D levels in Bangladeshi migrants. Recommending supplements could prevent potentially adverse health outcomes associated with vitamin D deficiency.

Lay Summary

Vitamin D deficiency is one example of mismatch between an evolved trait and novel environments. Here we compare vitamin D status of dark-skinned British-Bangladeshi migrants in the UK to Bangladeshis in Bangladesh and white British individuals. Migrants had lower levels of vitamin D and are at risk for associated pathologies.

The association of vitamin D levels and insulin resistance

OBJECTIVE

Vitamin D deficiency and insulin resistance have great prevalence in society. The latest studies indicate an inverse association between Vitamin D levels, insulin resistance, and Type 2 diabetes. The objective of this study was to investigate the effect of vitamin D status on insulin resistance.

METHODS

In a cross-sectional study, 2160 participants were randomly recruited from a nutrition clinic in Tehran, Iran, 1057 (48.9%) were female and 1103 (51.1%) male. Information was gathered by a questionnaire. Following 12-h fasting, fasting plasma glucose (FPG) and insulin levels, as well as 25-hydroxy vitamin D levels were measured. 2-H glucose and insulin levels measured after consumption of 75 g glucose, HOMA2-IR, and HOMA-β indices were then calculated.

RESULTS

The average serum Vitamin D was 22.3 + 8.9 nmol/L and the prevalence of Vitamin D deficiency was 100%. There was an inverse relationship between Vitamin D levels and age, BMI, waist circumference, and all metabolic parameters (p < 0.001 in all) and a direct association with levels of exercise. Two logistic regression models were used to adjust for confounding variables; firstly, for age, gender, and smoking and secondly, additionally for BMI and energy intake. Both models showed a significant inverse relationship between Vitamin D levels and FPG and insulin levels, 2-h glucose and insulin levels, and HOMA2-IR. The optimum cut point for vitamin D was calculated at about 25 nmol/L for preventing insulin resistance.

CONCLUSION

This study illustrated that there is a statistically significant inverse relationship between Vitamin D levels and insulin resistance.

Association of vitamin D deficiency with arterial stiffness in newly diagnosed hypertension

OBJECTIVE

Vitamin D has beneficial effects on vascular endothelial function, blood pressure (BP) and arterial stiffness. Arterial stiffness increases in early-stage hypertensive patients and it is a strong predictor of cardiovascular morbidity and mortality. The purpose of this study was to assess the association between serum 25-hydroxyvitamin D (25-OH D) levels and arterial stiffness in patients with newly diagnosed hypertension.

METHOD

Our study included 100 newly diagnosed hypertensive patients (63 male, 37 female and mean age: 51.7 ± 10.3 years) without cardiovascular disease, malignancy, chronic kidney disease and diabetes mellitus. Patients were divided into two groups: vitamin D deficiency group (<20 ng/ml) and normal vitamin D group (≥20 ng/ml). Twenty-four-hour, daytime and nighttime ambulatory BP readings were recorded. Mobil-O-Graph ARC solver algorithm was used to evaluate arterial stiffness parameters of pulse wave velocity (PWV) (m/s), augmentation index normalized with 75/min heart rate (Alx@75).

RESULTS

Patients with vitamin D deficency had higher values of Alx@75 and PWV values (20.9 ± 9 vs. 16.8 ± 6.9, P = 0.018 and 8.37 ± 1.16 vs. 6.9 ± 0.9, P = 0.001, respectively) despite similar 24-hour ambulatory BP monitoring in both groups. Level of serum calcium was significantly higher in vitamin D deficiency group (9.5 ± 0.23 vs. 9.3 ± 0.12, P = 0.007). Nighttime SBP was higher in vitamin D deficiency group (133.2 ± 14.3 mmHg vs. 126.3 ± 17.2 mmHg; P = 0.03) and also, vitamin D deficiency group had non-dipping SBP pattern compared to normal Vitamin D group (P = 0.013).

CONCLUSION

Vitamin D deficiency is associated with increased arterial stiffness in newly diagnosed hypertensive patients in terms of increased PWV and Alx@75 values.

Vitamin D3 induces mesenchymal-to-endothelial transition and promotes a proangiogenic niche through IGF-1 signaling

Although vitamin D3 (VitD3) prevents angiogenesis in cancer, VitD3 deficiency is associated with greater incidence of cardiovascular events in patients. We examined the influence of VitD3 on the angiogenic potential of mesenchymal stem cells (MSCs). VitD3 treatment increased the expression of proangiogenic molecules in MSCs, which exhibited an endothelial cell-like phenotype and promoted vascularization in vitro and in vivo. VitD3 activated the IGF-1 promoter and boosted IGF-1 receptor (IGF-1R) signaling, which was essential for the mesenchymal-to-endothelial transition (MEndoT) of MSCs. VitD3-treated MSCs created a proangiogenic microenvironment for co-cultured arterial endothelial cells, as well as aortic rings. The induction of MEndoT and angiogenesis promotion by VitD3-stimulated MSCs was attenuated by IGF-1R inhibitor picropodophyllin. We conclude that VitD3 promotes MEndoT in MSCs, and VitD3-treated MSCs augment vascularization by producing a proangiogenic niche through continued IGF-1 secretion. These results suggest a potential therapeutic role of VitD3 toward enhancing MSC-induced angiogenesis.

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Vitamin D3 (VitD3) treatment induces IGF-1 in mesenchymal stem cells (MSCs)

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VitD3 promotes mesenchymal-to-endothelial transition in MSCs via IGF-1 signaling

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Continued IGF-1 secretion by VitD3-treated MSCs creates a proangiogenic niche

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VitD3 may enhance MSC-induced angiogenesis through dual mechanisms

Wide-range direct detection of 25-hydroxyvitamin D3 using polyethylene-glycol-free gold nanorod based on LSPR aptasensor

Vitamin D is associated with various diseases such as obesity, digestive problems, osteoporosis, depression, and infections, which has emerged as an interest in public healthcare. Recently, vitamin D has received more attention because of the potential implication with coronavirus disease 2019. In this study, we developed a localized surface plasmon resonance (LSPR) aptasensor based on polyethylene-glycol(PEG)-free gold nanorods (AuNRs) for the wide-range and direct detection of 25-hydroxyvitamin D₃. The surfactant on AuNRs was removed by exchanging with polystyrene sulfonate (PSS) instead of PEG then the PSS was exchanged with citrate. By exchanging the stabilizer of AuNRs from PEG to PEG-free (i.e., citrate), the sensing efficiency of LSPR aptasensor was significantly improved. Additionally, LSPR aptasensor was functionalized with aptamer and blocking agent to enhance the sensing performance. The LSPR aptasensor achieved the direct, highly sensitive, and selective detection of 25-hydroxyvitamin D₃ over a wide concentration range (0.1-10⁵ ng/mL), with a limit of detection of 0.1 ng/mL. This detection range included the concentration of vitamin D from deficiency to excess. The PEG-free AuNR-based LSPR aptasensor affords a new avenue for the development of robust sensing technology for vitamins.

Correlation of Vitamin D Deficiency With Severity of Chronic Heart Failure as Assessed by Functional Class and N-Terminal Pro-Brain Natriuretic Peptide Levels

Introduction Chronic heart failure (CHF) is a major cause of mortality and morbidity in spite of tremendous advances in medical therapies. Vitamin D deficiency has been increasingly recognised in heart failure and its therapeutic as well as prognostic implications are debated. This study was carried out to examine the relationship of Vitamin D levels with severity of heart failure as assessed by NYHA functional class and serum N-terminal pro-brain natriuretic peptide (NT-pro-BNP) levels in vitamin D deficient patients with CHF. Methodology and results In this cross-sectional analysis, 119 patients of symptomatic CHF presenting to the outpatient/inpatient department of cardiology in a tertiary care institute in North India were screened. Patients were categorised according to their functional class as New York Heart Association (NYHA) class II, III, IV and their serum levels of vitamin D and NT-pro-BNP were measured. Out of 119 patients, 107 (90%) were found to have low vitamin D levels which were classified as insufficient (20-30 ng/ml) (n=25, 23%) or deficient (<20 ng/ml) (n=82,77%). The mean NT-pro-BNP levels increased significantly across functional class as 3783±6132 pg/ml, 7866±4383 pg/ml, 21115±11905 pg/ml in NYHA class II, III and IV respectively (p=0.000). The respective mean serum Vitamin D3 levels of 11.6±5.8ng/ml, 12.2±7.9 ng/ml, 14.4±8.9 ng/ml were not significantly different between classes (p=0.234). We found no correlation between serum NT-pro-BNP and serum vitamin D levels in the study cohort across various NYHA classes. In multivariate regression model, after adjusting for various co-variates, vitamin D levels were not significantly associated with NT-pro-BNP or functional class in patients with CHF. Conclusion Patients with CHF have a high prevalence (90%) of vitamin D deficiency. Although NT-pro-BNP levels increase significantly, vitamin D levels do not vary significantly with worsening NYHA classes. Further, no consistent significant correlation of vitamin D deficiency with NT-pro-BNP across different NYHA classes was observed. Thus, low levels of vitamin D didn't predict the severity and prognosis of patients with heart failure. .

DHCR7 rs12785878 T>C Polymorphism Is Associated With an Increased Risk of Early Onset of Alzheimer's Disease in Chinese Population

Background: Vitamin D insufficiency has been considered a risk factor for Alzheimer's disease (AD) in several studies. Recently, four single-nucleotide polymorphisms (SNPs) to be genome-wide significant for 25-hydroxyvitamin D [25(OH)D] were identified to have an association with the risk of AD. These include GC rs2282679 A>C, CYP2R1 rs10741657 T>C, DHCR7 rs12785878 T>C, and CYP24A1 rs6013897 T>A. However, the association between these polymorphisms and AD susceptibility in the Chinese population remains unclear.

Methods: A case-control cohort study was conducted in 676 AD patients (mean age at onset was 69.52 ± 10.90 years, male: 39.2%) and 551 healthy controls (mean age was 67.73 ± 6.02 years, male: 44.8%). Genotyping was determined by PCR and SNaPshot sequencing. To determine whether the four SNPs account for risks in AD in Chinese population, multivariate logistic regression models were performed. Stratified analysis was performed based on gender and age of onset of AD, separately. Statistical significance was set at 0.0125 (0.05/4) based on Bonferroni correction.

Findings:DHCR7 rs12785878 T>C was found to be significantly associated with an increased risk of early-onset Alzheimer's disease (EOAD) (n = 300, risk allele C, adjusted OR = 1.542, adjusted 95% CI = 1.176–2.023, p = 0.002). There was no statistical significance of the other three SNPs between the two groups.

Interpretation: Our results suggested that DHCR7 rs12785878 T>C might be associated with an increased risk of EOAD in the Chinese population, while other polymorphisms related to vitamin D insufficiency might not be. However, due to the limited data in this study, replication studies in a larger sample are required.

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.

Potential role of hypovitaminosis D and vitamin D supplementation during COVID-19 pandemic

Vitamin D deficiency is a pandemic disorder affecting over 1 billion of subjects worldwide and displaying a broad spectrum of implications on cardiovascular and inflammatory disorders. Since the initial reports of the association between hypovitaminosis D and COVID-19, Vitamin D has been pointed as a potentially interesting treatment for SARS-CoV-2 infection. We provide an overview on the current status of vitamin D deficiency, the mechanisms of action of vitamin D and the current literature on the topic, with a special focus on the potential implications for COVID-19 pandemic.

Vitamin D and Hospital Admission in Older Adults: A Prospective Association

The health effects of vitamin D are well documented, with increasing evidence of its roles beyond bone. There is, however, little evidence of the effects of vitamin D on hospitalisation among older adults. This study aimed to prospectively determine the relationship of vitamin D status in older adults with hospital admission and emergency department (ED) attendance. Trinity University of Ulster Department of Agriculture (TUDA) is a large cross-sectional study of older adults with a community population from three disease-defined cohorts (cognitive dysfunction, hypertension, and osteoporosis). Participants included in this analysis were recruited between 2008 and 2012. ED and hospital admission data were gathered from the date of TUDA participation until June 2013, with a mean follow up of 3.6 years. Of the 3093 participants, 1577 (50.9%) attended the ED during the period of follow-up. Attendees had lower mean serum 25(OH)D concentrations than non-attendees (59.1 vs. 70.6 nmol/L). Fully adjusted models showed an inverse association between vitamin D and ED attendance (Hazard Ratio (HR) 0.996; 95% Confidence Interval (CI) 0.995-0.998; p < 0.001). A total of 1269 participants (41%) were admitted to hospital during the follow-up. Those admitted had lower mean vitamin D concentrations (58.4 vs. 69.3 nmol/L, p < 0.001). In fully adjusted models, higher vitamin D was inversely associated with hospital admission (HR 0.996; 95% CI 0.994-0.998; p < 0.001) and length of stay (LOS) (β = -0.95, p = 0.006). This study showed independent prospective associations between vitamin D deficiency and increased hospitalisation by older adults. The need for further evaluation of current recommendations in relation to vitamin D supplementation, with consideration beyond bone health, is warranted and should focus on randomised controlled trials.

Sex-Specific Association between Serum Vitamin D Status and Lipid Profiles: A Cross-Sectional Study of a Middle-Aged and Elderly Chinese Population

Studies have shown that vitamin D status might be associated with dyslipidaemia, but results are conflicting and there might exist sex differences. The aim of our study was to explore the sex-specific association between vitamin D status and serum lipids and atherogenic index of plasma (AIP, a predictor for atherosclerosis) among Chinese middle-aged and elderly adults. A total of 4,021 middle-aged and elderly participants from a health management centre were included in this cross-sectional study. The individuals were classified into tertiles according to serum 25(OH)D. Linear and logistic regression models were used to estimate the association between vitamin D levels and serum lipids among the tertiles. The mean serum 25(OH)D level was 21.60 (16.60-27.20) ng/mL in all participants. After adjusting for potential confounders, a 10 ng/mL increase in 25(OH)D was associated with decreases of 1.156 mmol/L in triglycerides (TGs) and 0.068 in the AIP and an increase of 0.051 mmol/L in high-density lipoprotein cholesterol (HDL-C) in all subjects. In addition, 25(OH)D deficiency was associated with an increased prevalence of hypertriglyceridaemia (odds ratio (OR), 1.880; 95% confidence interval (CI), 1.351-2.615), hypoalphalipoproteinaemia/HDL (OR, 1.505; 95% CI, 1.146-1.977) and abnormal AIP (OR, 1.933; 95% CI, 1.474-2.534) in males, and 25(OH)D-deficient women had a 2.02-fold higher risk for hypoalphalipoproteinaemia/HDL than women with sufficient 25(OH)D levels (95% CI, 1.044-3.904; all p values <0.05). Vitamin D deficiency was positively associated with the prevalence of dyslipidaemia and abnormal AIP in the middle-aged and elderly Chinese population. And this association was stronger in men than in women.

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.

Hypophosphataemia, fibroblast growth factor 23 and third-generation intravenous iron compounds: a narrative review

Third-generation intravenous (i.v.) iron preparations are safe and efficacious and are increasingly used in the treatment of iron-deficiency anaemia. Hypophosphataemia is emerging as an established side-effect following the administration of certain compounds. Symptoms of hypophosphataemia can be masked by their similarity to those of iron-deficiency anaemia and both acute and chronic hypophosphataemia can be detrimental. Hypophosphataemia appears to be linked to imbalances in the metabolism of the phosphatonin fibroblast growth factor 23. In this narrative review, we discuss the possible pathophysiology behind this phenomenon, the studies comparing third-generation i.v. iron compounds, and the potential implications of the changes in fibroblast growth factor 23 and hypophosphataemia. We also present an algorithm of how to approach such patients requiring i.v. iron in anticipation of hypophosphataemia and how the impact related to it can be minimized.

Evaluation of the potential anticancer activity of different vitamin D metabolites on colorectal and breast cancer cell lines

OBJECTIVES

Vitamin D is very important for calcium and mineral metabolism, and many hypotheses appear to link sunlight exposure with cancer risk and prognosis. As many studies supported the antitumor effect of vitamin D we wanted to investigate the potential effect of multiple vitamin D metabolites.

METHODS

This study compared the anticancer effect of three inactive forms of vitamin D₃ which are; cholecalciferol, alfacalcidol, and calcifediol on two human cancer cell lines colorectal cancer (CaCo II) and breast cancer (MCF-7). All were examined after 24, 48, and 72 h continuous exposure using a colorimetric assay (MTT) seeded in 96-multiwell plates. Doxorubicin anticancer used as a standard agent for comparison, while normal skin fibroblast cells (HDFa) was used as our negative control. IC₅₀ values were calculated as indication of antitumor effect.

RESULTS

Broad-spectrum of cytotoxicity with IC₅₀ values ranging from 4 to 200 μM were found. Alfacalcidol was the most potent cytotoxic agents on colorectal cancer (CaCo II) and breast cancer (MCF-7) compared to cholecalciferol, and calcifediol. Both, alfacalcidol and calcifediol were more cytotoxic than cholecalciferol on the tested cell lines as they are partially active metabolites. Breast cancer (MCF-7) was the most sensitive to all metabolites at all-time intervals with the best IC₅₀ values of 4.35 μM ± 1.06 after 72 h continuous exposure of alfacalcidol.

CONCLUSIONS

Vitamin D metabolites are a potential option for cancer treatment along with or an alternative to chemo-therapeutics although extensive preclinical studies are required to prove this effect.

Early-life persistent vitamin D deficiency-induced cardiovascular dysfunction in mice is mediated by transient receptor potential C channels

BACKGROUND

Studies indicate that chronic vitamin D deficiency (VDD) may predispose to hypertension, yet, there is very little data characterizing its direct cardiac effects. Vitamin D modulates the function of transient receptor potential C cation channels (TRPC), which is a mechanosensitive cation channel that plays a role in cardiac slow-force responses to hemodynamic changes. The purpose of this study was to determine the cardiac effects of VDD and the potential role of TRPC.

METHODS

Three-week old mice were placed on a VDD or normal diet (ND) for 19 weeks. Mice were then implanted with radiotelemeters for the measurement of heart rate (HR) and heart rate variability (HRV), while a separate group was anesthetized to measure blood pressure (BP) and left ventricular function using an intraventricular probe. Animals were treated with a TRPC antagonist or vehicle after which they were challenged with dobutamine to measure cardiac responses.

RESULTS

VDD mice had significantly increased BP (72 ± 3 mmHg vs. 62 ± 2 mmHg) and left ventricular pressure (LVP) (84.6 ± 0.8 mmHg vs. 78.2 ± 2.0 mmHg), and decreased cardiac contractility (-3 % vs. + 11 %) and HR response (+8 % vs. + 13 %) to dobutamine when compared to ND. These responses were blocked by the TRPC antagonist. HRV decreased with increasing dobutamine doses in ND but not VDD mice, however, the antagonist had no effect.

CONCLUSION

VDD increases BP and alters cardiac mechanical function in mice, the latter appears to be mediated by TRPC, in particular TRPC6. Although the cardiac effects might be due to increased BP, it is likely that VDD also affects the function of the heart directly. This is the first study to demonstrate the potentially deleterious effects of VDD on cardiac function and the role of TRPC6 in this response.

Association of Vitamin D Deficiency with Diabetic Nephropathy

BACKGROUND

Low 25-hydroxyvitamin D (25OHD) levels are associated with the incidence of type 2 diabetes mellitus (T2DM). However, the association between 25OHD and metabolic health status or diabetic complications is inconclusive. We evaluated this relationship between vitamin D status and metabolic parameters and complications of T2DM.

METHODS

This study included 1,392 patients with T2DM who visited Eulji and Ewha Diabetes Center between January 2011 and August 2016. Anthropometric parameters and laboratory tests including glycated hemoglobin (HbA1c), lipid profile, liver and kidney function, and urinary albumin-to-creatinine ratio (UACR) were evaluated. Diabetic macro- and microvascular complications were determined through a medical record review. Serum 25OHD concentrations were measured by chemiluminescent immunoassay.

RESULTS

The mean 25OHD level was 16.8±9.6 ng/mL. Vitamin D deficiency (&lt;20 ng/mL) and severe deficiency (&lt;10 ng/mL) were observed in 990 (71.1%) and 351 (25.2%) participants, respectively. 25OHD level was positively correlated with age and highdensity lipoprotein cholesterol (HDL-C) level and negatively correlated with HbA1c, triglyceride level, and UACR. HDL-C and UACR were significantly associated with 25OHD after adjusting for other variables. Vitamin D deficiency was independently related to nephropathy after adjusting for confounding variables.

CONCLUSION

Vitamin D deficiency was common among Korean T2DM patients; it was independently associated with microalbuminuria and HDL level, and positively related to diabetic nephropathy.

VDR Gene Polymorphisms in Healthy Individuals with Family History of Premature Coronary Artery Disease

AIM

The gene encoding the vitamin D receptor (VDR) is considered in many studies to be a good candidate responsible for susceptibility to several diseases such as coronary artery disease (CAD). Epidemiological data show that cardiovascular disease is one of the major health problems in Polish society. Basic studies show that genetic factors play a significant role in the pathogenesis of CAD. We conducted this clinical study to determine if the VDR gene polymorphisms TaqI (rs731236), ApaI (rs7975232), and FokI (rs2228570) could predispose healthy individuals to an increased risk of premature CAD (P-CAD) incidents.

METHODS

We genotyped 845 subjects in a cohort consisting of 386 healthy volunteers with a documented P-CAD incident in their first-degree relatives and 459 healthy volunteers without family history (FH) of P-CAD. TaqI, ApaI, and FokI polymorphisms in VDR were genotyped using TaqMan assays and the endpoint genotyping method (qPCR). Statistical analyses were performed using the Power Analysis Software STATISTICA v.13.3.

RESULTS

Although no statistical significance was found for TaqI and ApaI genotype frequencies, the AA genotype of FokI polymorphism was significantly more frequent in the study group compared to the control group (24.61% vs. 16.99%). The results of logistic regression analysis suggested a significant association between FokI polymorphism and FH of P-CAD in heathy people under the recessive model (OR: 1.26 (1.07-1.49, p = 0.007)); however, the frequency of VDR haplotypes did not differ significantly between the control and study populations.

CONCLUSIONS

FokI polymorphism is may be associated with FH of P-CAD. FokI polymorphism may predispose to the development of P-CAD among healthy people over the next years.

Effect of cholecalciferol on unsaturated model membranes

Vitamin D plays an important role in many physiological processes, particularly calcium and phosphorous homeostasis. The biochemistry of vitamin D is also complex, encompassing a range of active molecules that may be either endogenous or dietary in origin. The role of lipids and fats in the production, processing and use of vitamin D is an interesting one, with a relative paucity of model studies into the interactions of vitamin D with lipidic systems such as micelles and vesicles. Here, we have studied the effect of vitamin D3 in simple unsaturated phospholipid systems. We used NMR and FTIR spectroscopy to investigate the effect of increasing vitamin D concentration on the structure and dynamics of the lipid chains and interfacial region. In order to link these model studies with more complex biomimetic environments, we compare results in the presence of buffer and vitamin D binding protein. We have also used DLS to determine that vitamin D3-DOPC vesicles can retain their size distribution for varying amounts of time in different conditions. We find that the acyl chain region of vitamin D3-DOPC membranes are generally disordered, and that the addition of buffer and/or protein alters the properties of the interfacial region.

The impact of methotrexate therapy with vitamin D supplementation on the cardiovascular risk factors among patients with psoriasis; a prospective randomized comparative study

BACKGROUND

Controlling psoriasis with various systemic treatments, including methotrexate, may significantly decrease associated cardiovascular risk problems.

OBJECTIVE

To assess the value of vitamin D supplementation on clinical response as well as changes in cardiovascular risk parameters in psoriasis patients treated with methotrexate.

METHODS

This prospective randomized comparative study included 30 patients with moderate to severe psoriasis divided randomly to receive either methotrexate alone (Mtx) or methotrexate plus intramuscular vitamin D (MtxD) for 3 months. Lipid profile, HsCRP, carotid intima-media thickness (CIMT) and blood pressure (BP) measurements were recorded before and after the therapy.

RESULTS

At end of study period, significant clinical improvement in both groups was observed. CIMT and systolic BP decreased in both groups but only statistically significant in Mtx group. HsCRP decreased in both groups but didn't reach statistical significance. We also observed, an increase in triglycerides and cholesterol levels in the Mtx group with the latter decreasing in the combined Mtx and vitamin D therapy group.

CONCLUSION

Treating psoriasis with methotrexate may decrease cardiovascular disease risk factors. Adding vitamin D supplementation to methotrexate may protect lipid homeostasis, specifically cholesterol and triglycerides.

Long-Term Bioavailability of Single Doses of Intramuscular Vitamin D2

OBJECTIVE

We sought to determine the long-term bioavailability of single doses of intramuscular (IM) vita-min D₂ (D₂) in healthy adults.

METHODS

Forty healthy volunteers with hypovitaminosis D received a single dose of 200,000, 400,000, or 600,000 IU intramuscular D₂ or no treatment. Levels of 25-hydroxyvitamin D₂ (25&lsqb;OH]D₂) and 25-hydroxyvitamin D₃ (25&lsqb;OH]D₃) in serum were measured by liquid chromatography-tandem mass spectrometry. Vitamin D binding protein (DBP) and intact parathyroid hormone (iPTH), bone turnover markers (BTMs), and serum and urinary calcium were also measured.

RESULTS

After a single dose of D₂ injection, the level of 25(OH)D₂ increased slowly and reached a plateau at 8 weeks. The plateau remained stable for 12 weeks. The mean increase in 25(OH)D₂ was 6.8, 9.6, or 15.6 ng/mL after injection of 200,000 IU, 400,000 IU, or 600,000 IU D₂. Although endogenous 25(OH)D₃ levels were reduced by IM D₂, the total 25(OH)D levels increased by 5.0, 7.0, or 10.3 ng/mL in average after injection of 200,000 IU, 400,000 IU, or 600,000 IU D₂. The iPTH levels were also decreased by IM D₂. However, levels of serum calcium, BTMs, and DBP and urinary calcium were not altered by IM D₂.

CONCLUSION

A single dose of 200,000 IU, 400,000 IU, or 600,000 IU IM D₂ raises total 25-hydroxyvitamin D levels by 5.0, 7.0, or 10.3 ng/mL on average for at least 12 weeks and reduces iPTH and endogenous 25(OH)D₃ levels without affecting levels of serum calcium, BTMs, DBP, and urinary calcium.

Association of vitamin D pathway gene polymorphisms with vitamin D level during pregnancy was modified by season and vitamin D supplement

BACKGROUND & AIMS

This study aims to explore the associations of vitamin D (VD) metabolic pathway gene with 25(OH)D level in pregnant women and the interactions of SNP with season and VD supplement.

METHODS

A total of 2658 pregnant women were selected from Zhoushan Pregnant Women Cohort study. Gestational 25(OH)D level and single nucleotide polymorphism (SNP) of VD metabolic pathway gene were detected. Multilinear regression models were used to estimate associations of SNPs with gestational 25(OH)D levels. Stratified analyses were performed to test the interactions of SNP with season and VD supplements.

RESULTS

The mutations of rs2298849 and rs7041 on the GC gene were respectively associated with higher 25(OH)D in the first and third trimester; the mutations of seven SNPs (rs1155563, rs16846876, rs17467825, rs2282679, rs2298850, rs3755967, and rs4588) on the GC gene were respectively associated with lower 25(OH)D both in the first and third trimester, and lower changes in 25(OH)D during late pregnancy. The mutations of above seven SNPs, except for rs1155563, were also respectively associated with lower 25(OH)D in the second trimester, but to a lesser extent; Besides, pregnant women with mutation on CYP24A1-rs2209314 had a higher increment in 25(OH)D than their counterparts in the second trimester. The increasing dose effect of Gc isoform on 25(OH)D was observed. The associations of GC and LRP2 genes with 25(OH)D modified by season and VD supplements.

CONCLUSIONS

The polymorphisms of VD metabolic pathway gene were associated with gestational 25(OH)D, and the associations differ by seasons and VD supplements. Gc isoform exerted a profound influence on gestational 25(OH)D.

Role of vitamin D in the pathogenesis of atheromatosis

BACKGROUND AND AIMS

Cardiovascular disease is the main cause of death worldwide, but the collective efforts to prevent this pathological condition are directed exclusively to individuals at higher risk due to hypercholesterolemia, hypertension, obesity, diabetes. Recently, vitamin D deficiency was identified as a risk factor for cardiovascular disease in healthy people, as it predisposes to different vascular dysfunctions that can result in plaque development and fragility. In this scenario, the fundamental aim of the study was to reproduce a disease model inducing vitamin D deficiency and atheromatosis in ApoE-/- mice and then to evaluate the impact of this vitamin D status on the onset/progression of atheromatosis, focusing on plaque formation and instability.

METHODS AND RESULTS

In our murine disease model, vitamin D deficiency was achieved by 3 weeks of vitamin D deficient diet along with intraperitoneal paricalcitol injections, while atheromatosis by western-type diet administration. Under these experimental conditions, vitamin D deficient mice developed more unstable atheromatous plaques with reduced or absent fibrotic cap. Since calcium and phosphorus metabolism and also cholesterol and triglycerides systemic concentration were not affected by vitamin D level, our results highlighted the role of vitamin D deficiency in the formation/instability of atheromatous plaque and, although further studies are needed, suggested a possible intervention with vitamin D to prevent or delay the atheromatous disease.

CONCLUSIONS

The data obtained open the question about the potential role of the vitamins in the pharmacological treatments of cardiovascular disorders as coadjutant of the primary drugs used for these pathologies.

Effect of Vitamin D Supplementation on the Regulation of Blood Pressure in Iranian Patients with Essential Hypertension: A Clinical Trial

BACKGROUND

Low serum vitamin D level is associated with both high blood pressure and incidence of primary hypertension. Experimental studies suggest that vitamin D supplements may reduce blood pressure.

OBJECTIVE

The aim of this study was to investigate whether vitamin D supplementation reduces systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) in Iranian patients with essential hypertension.

METHOD

A total of 173 patients with essential hypertension participated in this open-label clinical trial. SBP, DBP, and serum vitamin D levels were measured at baseline and at the end of the study. Vitamin D was administered at a dose of 50,000 IU/week, and 1000 IU/day in patients with serum vitamin D levels <20 ng/mL and 20-30 ng/mL, respectively, for 8 weeks.

RESULTS

Based on serum vitamin D levels, 45.1%, 17.3%, and 29.5% of patients were deficient, insufficient, and sufficient for vitamin D intake, respectively. Baseline serum levels of vitamin D were not correlated with SBP, DBP, and MAP at the beginning of the study (p = ns). Multiple logistic regression analysis revealed that the risk of vitamin D deficiency was 2.5-fold times higher in women than in men (p = 0.03). After 8 weeks of supplementation with vitamin D, mean SBP and MAP were significantly reduced by 5.5 ± 16.16 (p = 0.01) and 3.7 ± 9.24 (p = 0.004) mmHg, respectively. Neither sex nor age could significantly predict BP response to vitamin D supplementation.

CONCLUSION

Vitamin D supplementation may significantly reduce SBP and MAP but not DBP in patients with essential hypertension.

Impact of Guidelines on Hypertension Control in the Elderly

BACKGROUND

Hypertension control is a crucial measure to reduce cardiovascular (CV) risk, and blood pressure (BP) treatment targets have been recently revised to address this issue. However, achieving the recommended goal may be challenging.

OBJECTIVE

We aimed to assess the prevalence of uncontrolled hypertension, according to the US hypertension guidelines, among elderly participants in an Italian nationwide epidemiological survey, the relevant clinical correlates, and the agreement with the application of the European guidelines.

METHODS

Elderly (≥65y) volunteers enrolled in an Italian nationwide survey underwent BP measurement using standard protocols. Uncontrolled hypertension was defined as BP≥130/80 mmHg. Agreement of this definition with those from European guidelines (≥140/90 mmHg; ≥140/80 mmHg) was tested using Cohen's kappa. Selfreported information on modifiable/non-modifiable CV risk factors was also collected.

RESULTS

Of the 13,162 treated hypertensive elderly, 69.8% had uncontrolled hypertension. They tended to be overweight/obese men with diabetes. Overall agreement between US and European guidelines was poor to good (κ = 0.289, p<0.001 and κ = 0.691, p<0.001 based on the 140/90 and 140/80 mmHg threshold, respectively). Elderly participants with controlled hypertension were more likely to report a history of CV or chronic kidney disease. No difference in lifestyle habits was observed by BP control status.

CONCLUSION

Real-world data identify limited concordance between guidelines in terms of BP target achievement among older hypertensive Italians and highlights the need to spread awareness of the CV risk, especially in the presence of diabetes and obesity.

Relationship of Vitamin D Status with Thyroid Autoimmunity in New Onset Autoimmune Hypothyroidism

Background

Study of serum vitamin D level in new onset hypothyroid patients and its correlation with thyroid related parameters and antibody titers.

Objectives

We aimed to compare serum vitamin D level in new onset hypothyroid patients versus controls. Furthermore we evaluated for any association of vitamin D status with hypothyroid state and its correlation with various thyroid related parameters.

Methodology

In this cross sectional study , 61 new onset hypothyroid subjects (cases) and 40 age, sex and BMI matched healthy individuals (controls) were recruited. Measurements of serum vitamin D, thyroid hormones, thyroid peroxidase antibody (TPO-Ab), parathyroid hormone (PTH), calcium and phosphorus were done for all study participants.

Results

The mean serum vitamin D in cases (22.95±8.59 ng/ml) was significantly lower than the controls (27.9±7.85 ng/ml) (p<0.01). The prevalence of vitamin D deficiency was significantly higher among hypothyroid subjects than controls (p=0.009). Hypothyroid subjects with vitamin D deficiency group had significantly higher TSH level, greater thyroid volume and elevated anti TPO titres than those with vitamin D sufficiency. Serum vitamin D level had significant inverse correlation with anti TPO-Abtiters even after adjustment for age, sex and BMI.

Conclusion

Serum vitamin D is significantly low in new onset hypothyroid patients than healthy controls. Hypothyroid patients with vitamin D deficiency have significantly higher TSH, antibody titres and thyroid volume. A significant negative correlation was observed between serum vitamin D leveland anti TPO titres. Moreover, serum vitamin D remained an independent predictor of TPO level among hypothyroid subjects.

Vitamin D and cardiovascular health

The principal source of vitamin D in humans is its biosynthesis in the skin through a chemical reaction dependent on sun exposure. In lesser amounts, the vitamin can be obtained from the diet, mostly from fatty fish, fish liver oil and mushrooms. Individuals with vitamin D deficiency, defined as a serum level of 25 hydroxyvitamin D < 20 ng/dl, should be supplemented. Vitamin D deficiency is a prevalent global problem caused mainly by low exposure to sunlight. The main role of 1,25 dihydroxyvitamin D is the maintenance of calcium and phosphorus homeostasis. However, vitamin D receptors are found in most human cells and tissues, indicating many extra-skeletal effects of the vitamin, particularly in the immune and cardiovascular (CV) systems. Vitamin D regulates blood pressure by acting on endothelial cells and smooth muscle cells. Its deficiency has been associated with various CV risk factors and appears to be linked to a higher mortality and incidence of CV disease (CVD). Several mechanisms have been proposed relating vitamin D deficiency to CV risk factors such as renin-angiotensin-aldosterone system activation, abnormal nitric oxide regulation, oxidative stress or altered inflammatory pathways. However, in the latest randomized controlled trials no benefits of vitamin D supplementation for CVD have been confirmed. Although more work is needed to establish the protective role of vitamin D in this setting, according to current evidences vitamin D supplements should not be recommended for CVD prevention.

Association of serum 25-Hydroxy vitamin D with total and regional adiposity and cardiometabolic traits

Background

Lower serum 25-hydroxyvitamin D [25(OH)D] is associated with greater adiposity and adverse cardiometabolic risk profile. The evidence is inconsistent among South Asian Indians. We aimed to examine associations between 25(OH)D and cardiovascular (CVD) risk markers in a rural and urban cohort from South India.

Subjects/Methods

In this cross sectional study, 373 individuals (men, n = 205) underwent detailed CVD risk marker assessment including anthropometry [body mass index (BMI), waist, (WC) and hip circumferences (HC)], body composition analysis using dual energy x-ray absorptiometry (DXA), blood pressure and biochemical analysis (glucose, insulin and lipids). The distribution of CVD risk factors were compared across serum 25(OH)D levels, stratified as deficiency (<20 ng/ml), insufficiency (20 to 29 ng/ml) and normal (≥30 ng/ml) levels. Multiple regression analysis, adjusting for potential confounders, was used to study associations of 25(OH)D with adiposity and cardiometabolic traits.

Results

The mean and standard deviation (SD) of age, BMI and 25(OH)D levels were 41.4 (1.1) years, 25.5 (4.8) kg/m² and 23.4 (10.4) ng/ml respectively. The prevalence of 25(OH)D deficiency was 39.9% in this cohort. Individuals in the 25(OH)D deficiency category had significantly higher mean (SD) BMI [26.6 (5.1) kg/m²], waist circumference [89.9 (12.5) cm] and total fat mass [20.6 (7.9) kg] compared with the Vitamin D sufficient group [BMI: 24.0 (4.4); WC 84.7 (12.0); total fat mass: 15.2 (6.8)]. Significantly inverse associations were observed with DXA measured total and regional fat depots with 25(OH)D levels, while anthropometric indices of adiposity showed significant inverse association only in women. After adjusting for total fat mass, no significant associations were observed between 25(OH)D and the cardiometabolic traits.

Conclusions

Our results confirm that lower 25(OH)D is independently associated with both total and regional adiposity, but not with cardiometabolic traits, in this population.

Vitamin D for prevention of sternotomy healing complications: REINFORCE-D trial

Background

Most cardiac surgery patients undergo median sternotomy during open heart surgery. Sternotomy healing is an arduous, very complex, and multifactorial process dependent on many independent factors affecting the sternum and the surrounding soft tissues. Complication rates for median sternotomy range from 0.5 to 5%; however, mortality rates from complications are very variable at 7–80%. Low calcidiol concentration below 80 nmol/L results in calcium absorptive impairment and carries a risk of bone loss, which is considered as a risk factor in the sternotomy healing process. The primary objective of this clinical trial is to compare the incidence of all postoperative sternotomy healing complications in two parallel patient groups administered cholecalciferol or placebo. The secondary objectives are focused on general patient recovery process: sternal bone healing grade at the end of the trial, length of hospitalization, number of days spent in the ICU, number of days spent on mechanical lung ventilation, and number of hospital readmissions for sternotomy complications.

Methods

This clinical trial is conducted as monocentric, randomized, double-blind, placebo-controlled, with planned enrollment of 600 patients over 4 years, approximately 300 in the placebo arm and 300 in the treatment arm. Males and females from 18 to 95 years of age who fulfill the indication criteria for undergoing cardiac surgery with median sternotomy can be included in this clinical trial, if they meet the eligibility criteria.

Discussion

REINFORCE-D is the first monocentric trial dividing patients into groups based on serum calcidiol levels, and with dosing based on serum calcidiol levels. This trial may help to open up a wider range of postoperative healing issues.

Trial registration

EU Clinical Trials Register, EUDRA CT No: 2016-002606-39. Registered on September 8, 2016.

Serum Vitamin D and Depressive Symptomatology among Boston-Area Puerto Ricans

BACKGROUND

Low vitamin D status, assessed using serum 25-hydroxyvitamin D [25(OH)D] concentration, has been associated with depression, but research among minority populations, such as Puerto Ricans is limited. We examined the association between serum 25(OH)D and self-reported depressive symptomatology across 3 waves of follow-up in a cohort of Puerto Rican adults residing in Massachusetts.

OBJECTIVES

We evaluated the cross-sectional and longitudinal associations between serum 25(OH)D and self-reported depressive symptoms in the Boston Puerto Rican Health Study (BPRHS) cohort.

METHODS

Participants of the BPRHS were evaluated for depressive symptoms using the Center for Epidemiologic Studies Depression Scale (CES-D). Serum 25(OH)D was measured at baseline (n = 1434), year 2 (n = 1218), and year 5 (n = 914). We categorized serum 25(OH)D concentration as sufficient (≥20 ng/mL), insufficient (12 to <20 ng/mL), and deficient (<12 ng/mL). Multivariable linear regression was used for cross-sectional analyses at baseline, and repeated measures mixed effects modeling was used over 3 waves of follow-up for longitudinal analyses. We conducted sensitivity analyses in vitamin D supplement nonusers and participants with complete data on baseline serum 25(OH)D and CES-D at all 3 visits.

RESULTS

Serum 25(OH)D concentration was not associated with CES-D score in cross-sectional analysis [β = -0.85; 95% CI: -2.80, 1.10 for deficient compared with sufficient 25(OH)D; P-trend = 0.59] or in longitudinal analyses over 5 y [β = -0.41; 95% CI: -1.95, 1.13 for deficient compared with sufficient 25(OH)D; P-trend = 0.93]. Results were similar in sensitivity analyses restricted to vitamin D supplement nonusers (n = 1371) and in analyses conducted in participants with complete measures of baseline serum 25(OH)D and CES-D score at all 3 visits (n = 887) [β = -0.12; 95% CI: -1.98, 1.74 for deficient compared with sufficient 25(OH)D; P-trend = 0.93].

CONCLUSIONS

We did not observe a significant association between serum 25(OH)D and depressive symptomatology in the BPRHS cohort.

Atherosclerosis and Inflammatory Bowel Disease-Shared Pathogenesis and Implications for Treatment

Atherosclerosis and inflammatory bowel disease (IBD) are often regarded as 2 distinct entities. The commonest manifestation of atherosclerosis is ischemic heart disease (IHD), and an association between IHD and IBD has been reported. Atherosclerosis and IBD share common pathophysiological mechanisms in terms of their genetics, immunology, and contributing environmental factors. Factors associated with atherosclerosis are implicated in the development of IBD and vice versa. Therefore, treatments targeting the common pathophysiology pathways may be effective in both conditions. The current review considers the pathophysiological pathways that are shared between the 2 conditions and discusses the implications for treatment and research.

Measurement of plasma 25-hydroxyvitamin D2, 25-hydroxyvitamin D3 and 3-epi-25-hydroxyvitamin D3 in population of patients with cardiovascular disease by UPLC-MS/MS method

Vitamin D has a potential role in protecting against cardiovascular disease (CVD). Serum 25-hydroxyvitamin D (25D) is the most widely used indicator of vitamin D status in the human body. 25D is estimated as total of 25-hydroxyvitamin D2 (25D2) and 25-hydroxyvitamin D3 (25D3). However, the presence of 3-epi-25-hydroxyvitamin D3 (3epi25D3) can affect 25D measurement. In this research a novel validated UPLC-MS/MS technique was developed to measure three vitamin D metabolites, 25D2, 25D3 and 3epi25D3 in human plasma. A liquid-liquid extraction using hexane was applied for isolation of the analytes from the samples. A chromatographic separation was achieved in a Kinetex F5 analytical column with isocratic elution (water and methanol with 0.1% methanoic acid, 20:80 v/v). Mass spectrometry detection of the metabolites was performed in a triple-quadruple tandem mass spectrometer under positive ion mode. Concentrations of the analytes were estimated in plasma samples of 54 patients. Validation parameters of the UPLC-MS/MS method, including linearity, precision, accuracy, and stability, fulfilled the requirements for bioanalytical assays. The deficient concentration of 25D (<20 ng/mL) was stated in over 60% of patients. 3epi25D3 was present in 78% of samples and its relative amount ranged from 0 to 54.1% of 25D concentration. The analysis of 25D2, 25D3 and 3epi25D3 by the validated UPLC-MS/MS method in plasma of patients with CVD permitted the classification of the patients with insufficient levels of 25D. 3epi25D3 might be relevant in the classification of vitamin D status.

Autophagy participates in the protection role of 1,25-dihydroxyvitamin D3 in acute myocardial infarction via PI3K/AKT/mTOR pathway

Vitamin D deficiency is associated with acute myocardial infarction (AMI); thus we aimed to explore improvement effects of 1,25-dihydroxyvitamin D3 (VD3) on the AMI and its potential mechanism. AMI models were constructed using male C57/BL6J mice and randomly treated with normal saline or VD3, using sham rats as control. Heart functions, myocardial damage, apoptosis, and inflammation were evaluated. Cardiomyocytes isolated from 3-day-old suckling mice were used for in vitro verification. After VD3 treatment, AMI-induced cardiac dysfunction was reversed with better cardiac function parameters. VD3 treatment reduced inflammatory cell infiltration and myocardial infarction area accompanied by the reduction of inflammatory factors and myocardial infarction markers compared with the AMI group. VD3 treatment obviously alleviated AMI-induced myocardial apoptosis, along with Bcl-2 upregulation and downregulation of caspase-3, caspase-9, and Bax. Both in vivo and in vitro experiments revealed that VD3 enhanced the expression of LC3II and Beclin-1 and decreased soluble p62. Furthermore, VD3 enhanced the AMI-caused inhibition of PI3K, p-AKT, and p-mTOR expression, which was conversely reversed by the addition of 3-methyladenine in vitro. The study highlights the improvement effects of VD3 on cardiac functions. We proposed a potential mechanism that VD3 protects against myocardial damage, inflammation, and apoptosis by promoting autophagy through PI3K/AKT/mTOR pathway.

Relationship between risk markers for cardiovascular disease and peri-implant diseases

Background

The aim of this paper is to explore the serum biochemical parameters also known as risk markers for cardiovascular system, in individuals who have received dental implant treatment, and to reveal risk factors for peri-implant diseases.

Methods

The study included 58 subjects with peri-implantitis, 49 subjects with peri-implant mucositis, and 49 healthy subjects. All the subjects were assessed in terms of both peri-implant clinical parameters—probing depth (PD), bleeding on probing (BOP), the type of prosthesis, gingival index (GI), keratinized mucosa width (KMW), and plaque index (PI)—and serum biochemical parameters (e.g., LDL cholesterol, HDL cholesterol, triglyceride, total cholesterol, vitamin D, uric acid, white blood cell (WBC), neutrophil, hemoglobin (Hb), and platelet counts).

Results

KMW was the lowest in the peri-implantitis group. Compared with the other groups, the peri-implantitis group showed significantly higher levels of triglyceride, uric acid, and WBC. The peri-implantitis group had the lowest level of vitamin D. Triglyceride and uric acid levels had positive correlations with peri-implant clinical parameters.

Conclusion

High levels of triglyceride and uric acid may pose a risk for both peri-implant diseases and cardiovascular diseases. Prior to dental implant surgery, patients’ serum biochemical parameters should be checked.

Prevention and Management of Gestational Diabetes Using Vitamin D Supplementation: An Overview and Appraisal of Clinical Trials

A number of studies have examined the role of vitamin D in reproductive processes and disorders of pregnancy such as gestational diabetes mellitus (GDM). Although observational studies have linked maternal vitamin D deficiency with a plethora of adverse pregnancy outcomes including GDM, intervention trials generally do not support the use of vitamin D supplementation for GDM prevention or management. This narrative review provides an up-to-date overview and critical appraisal of randomised controlled trials (RCTs) to describe the current state of knowledge regarding the efficacy of vitamin D supplementation for preventing and/or managing GDM. Overall, although RCT data indicates a potential benefit of vitamin D in maternal glycaemic control, results are highly disparate and the data published to date have not conclusively established the efficacy of vitamin D in GDM prevention. There are, however, several limitations within the existing literature, including some considerable challenges that are unique to vitamin D trials, which should be carefully considered in the interpretation of the evidence and design of future studies. For now, many unanswered questions remain, and there is still a need for adequately powered and well-designed trials before routine supplementation can be recommended in the context of GDM.

Effects of Vitamin D Supplementation on Omentin-1 and Spexin Levels, Inflammatory Parameters, Lipid Profile, and Anthropometric Indices in Obese and Overweight Adults with Vitamin D Deficiency under Low-Calorie Diet: A Randomized Placebo Controlled Trial

Background and Aims

Improved vitamin D levels can have a favorable effect on some metabolic variables. The objective of the current study was to determine the effects of vitamin D supplementation during a weight-loss intervention on the levels of omentin-1, spexin, lipid profiles, and inflammatory factors in obese and overweight participants.

Methods and Materials

In this double-blind placebo-controlled randomized clinical trial, 70 overweight and obese participants with vitamin D deficiency (25(OH)D ≤ 20 nmol/L) were assigned into the intervention (a daily dose of 2,000 IU vitamin D + low-calorie diet) and placebo (placebo + low-calorie diet) groups for 8 weeks. Anthropometric parameters, serum levels of 25-hydroxy vitamin D (25(OH)D), lipid profiles, omentin-1 and spexin levels, high-sensitivity C-reactive protein (hs-CRP), and soluble intercellular adhesion molecule-1 (sICAM-1) concentrations were assessed before and after the intervention.

Results

Vitamin D supplementation after the intervention led to a significant decrease in triglycerides (TG) (P = 0.02), very-low-density lipoprotein-cholesterol (VLDL-C) (P = 0.02), and hs-CRP (P = 0.03) concentrations and a significant increase in the serum vitamin D level (P < 0.001). Furthermore, after adjusting for baseline values, age, and baseline BMI, the levels of serum high-density lipoprotein-cholesterol (HDL-C) (P = 0.01) increased significantly, and a significant reduction was observed in the concentration of sICAM-1 (P = 0.01) in the intervention group. However, we did not find any significant difference in serum omentin-1 and spexin concentrations between the groups after intervention.

Conclusions

Vitamin D supplementation along with a low-calorie diet (LCD) program for 8 weeks significantly decreased the inflammatory markers in obese individuals, while it did not alter serum omentin-1 and spexin concentrations.

Controversies in Vitamin D: A Statement From the Third International Conference

The Third International Conference on Controversies in Vitamin D was held in Gubbio, Italy, September 10–13, 2019. The conference was held as a follow‐up to previous meetings held in 2017 and 2018 to address topics of controversy in vitamin D research. The specific topics were selected by the steering committee of the conference and based upon areas that remain controversial from the preceding conferences. Other topics were selected anew that reflect specific topics that have surfaced since the last international conference. Consensus was achieved after formal presentations and open discussions among experts. As will be detailed in this article, consensus was achieved with regard to the following: the importance and prevalence of nutritional rickets, amounts of vitamin D that are typically generated by sun exposure, worldwide prevalence of vitamin D deficiency, the importance of circulating concentrations of 25OHD as the best index of vitamin D stores, definitions and thresholds of vitamin D deficiency, and efficacy of vitamin D analogues in the treatment of psoriasis. Areas of uncertainly and controversy include the following: daily doses of vitamin D needed to maintain a normal level of 25OHD in the general population, recommendations for supplementation in patients with metabolic bone diseases, cutaneous production of vitamin D by UVB exposure, hepatic regulation of 25OHD metabolites, definition of vitamin D excess, vitamin D deficiency in acute illness, vitamin D requirements during reproduction, potential for a broad spectrum of cellular and organ activities under the influence of the vitamin D receptor, and potential links between vitamin D and major human diseases. With specific regard to the latter area, the proceedings of the conference led to recommendations for areas in need of further investigation through appropriately designed intervention trials. © 2020 The Authors. JBMR Plus published by Wiley Periodicals LLC. on behalf of American Society for Bone and Mineral Research.

Is there a link between vitamin D status, SARS-CoV-2 infection risk and COVID-19 severity?

The outbreak of COVID-19 emerged in December 2019 rapidly spread across the globe and has become pandemic. Little is known about the protective factors of this infection, which is equally distributed between genders and different ages while severe and poor prognosis cases are strongly associated to old males and the presence of comorbidities. Thus, preventive measures aiming at reducing the number of infection and/or their severity are strongly needed. Vitamin D has got great attention and has been claimed as potentially protective against the infection since it may be associated with immunocompetence, inflammation, aging, and those diseases involved in determining the outcomes of COVID-19. This narrative review aims at collecting the literature available on the involvement of the vitamin D status in the pathogenesis of COVID-19 and the putative utility of vitamin D supplementation in the therapeutics. It emerges that a poor vitamin D status seems to associate with an increased risk of infection whereas age, gender and comorbidities seem to play a more important role in COVID-19 severity and mortality. While randomized control trials are needed to better inquire into this topic, vitamin D supplementation may be useful beside its potential effects on SARS-CoV-2 infection and COVID-19.

The relationship between circulating vitamin D3 and subclinical atherosclerosis in an elderly Asian population

The current evidence regarding the association between vitamin D deficiency and cardiovascular diseases/metabolic disorders is contradictory and inconclusive. In this large-scale observational study, we investigated the relationship between the serum 25-hydroxy vitamin D3 [25(OH)D] concentration and subclinical atherosclerosis in an elderly Asian population. In the I-Lan longitudinal study (ILAS), 1798 elderly, aged 50 and older, were enrolled. For each subject, serum 25-hydroxy vitamin D3 [25(OH)D] concentration and demographic data were recorded. The participants were divided into two groups according to their serum 25(OH)D level (sufficient, > 20 ng/mL and deficient, ≤ 20 ng/mL). Carotid intima-media thickness (cIMT) was measured at bilateral common carotid arteries. Subclinical atherosclerosis was defined as a mean cIMT > 0.81 mm. The mean subject age was 64 ± 9 years old, and 604 (33.6%) were identified as having serum 25(OH)D level ≤ 20 ng/mL. Subjects with serum 25(OH)D level ≤ 20 ng/mL were younger, more likely to be female and smoker, and had a higher incidence of hypertension, dyslipidemia, and metabolic syndrome, compared to those with serum 25(OH)D level > 20 ng/mL. Additionally, patients with serum 25(OH)D level ≤ 20 ng/mL were associated with a lower risk of subclinical atherosclerosis (crude OR: 0.63, 95% CI 0.50–0.81, p < 0.001), according to univariate analysis. However, after adjusting for gender and age, serum 25(OH)D level ≤ 20 ng/mL was not a significant risk factor for subclinical atherosclerosis. Serum 25(OH)D level ≤ 20 ng/mL was not an independent risk factor for subclinical atherosclerosis in this large elderly Asian population. Association observed in the univariate analysis may be confounded by gender or comorbidities.

Association between Vitamin D and Candida-Associated Denture Stomatitis

Candida-associated denture stomatitis (CADS) is a fungal infection affecting 60–65% of denture wearers. Its etiology is complex and multifactorial and often associated with host immunodeficiency. Evidence exists that vitamin D has potential immunomodulatory and anti-inflammatory effects. The aim of this case–control study was to assess the association between vitamin D levels and CADS. The study included 32 complete denture wearers with CADS and 32 sex- and age-matched complete denture wearers without CADS. The patients were clinically examined, and the severity of denture stomatitis was assessed according to Newton’s classification scale. The serum vitamin D level was determined via the use of an electrochemiluminescence assay. The vitamin D level in the CADS group and control group was 54.68 ± 17.07 and 56.82 ± 17.75 nmol/L, respectively. There was no significant difference between the groups (p = 0.622). Univariate logistic regression analysis showed that the presence of CADS was not associated with hypovitaminosis D (odds ratio (OR) = 1.44; 95% confidence interval (CI) = 0.37–5.54). It can be concluded that vitamin D is not associated with CADS and does not play a significant role in host susceptibility to CADS. This finding suggests that vitamin D screening is not indicated routinely in patients with Candida-associated denture stomatitis.

Does serum vitamin D level affect the association between cardiovascular health and cognition? Results of the Cardiovascular and Metabolic Diseases Etiology Research Center (CMERC) study

BACKGROUND AND PURPOSE

Few studies have assessed the role of vitamin D in the association between cardiovascular risk factors and cognitive function. Here, the aim was to investigate the association between cardiovascular health (CVH) and cognitive function according to vitamin D level in a middle-aged Korean population.

METHODS

This cross-sectional study included 840 men and 1811 women (mean age 57.2 years) from the Cardiovascular and Metabolic Diseases Etiology Research Center study baseline enrolment (2013-2018). Life's Simple 7 tools from the American Heart Association were used to assess CVH. Cognitive function was evaluated using the Mini-Mental State Estimation for Dementia Screening (MMSE-DS), and the serum 25-hydroxyvitamin D level was measured.

RESULTS

In the adjusted generalized linear regression models, no significant association between a high Life's Simple 7 score (4-7 metric at optimal level) and MMSE-DS score (β = 0.01, P = 0.93) was found. Amongst men with a high vitamin D level, the high Life's Simple 7 score group showed a significantly higher MMSE-DS score (β = 0.48, P = 0.03). However, amongst men in the low vitamin D group, the association was opposite with no statistical significance (β = -0.23, P = 0.08). In women, the results were similar, but both strata according to vitamin D level showed no statistical significance.

CONCLUSIONS

Our findings suggest that vitamin D is an effect modifier in the association between CVH and cognition, especially in men.

Association between serum vitamin D levels and venous thromboembolism (VTE): A systematic review and meta-analysis of observational studies

OBJECTIVE

Although many studies have attempted to unravel the relationship between vitamin D deficiency and the incidence of VTE, the results remained inconsistent. To address this discrepancy, we performed a systematic review and meta-analysis to precisely disentangle the relationship between serum vitamin D levels and VTE risk.

METHODS

The Web of Science, Scopus, PubMed/Medline, Embase, and Google Scholar databases were searched for all available observational studies that reported the risk of venous thromboembolism (VTE) based on serum vitamin D levels categories. The search was performed up to March 2020.

RESULTS

Seven studies were included. The overall analysis showed a significantly increased risk of VTE in subjects with low levels of serum vitamin D compared with those with normal vitamin D levels (RR = 1.34; 95% CI: 1.07-1.69; P = 0.011). In a sensitivity analysis, we did not observe a significant effect of any individual study on the combined effect sizes. Nevertheless, significant heterogeneity was present among the studies (Cochrane Q test, p = 0.018, I² = 61%). In the stratified analysis, low vitamin D levels were positively associated with an increased risk of VTE in prospective population-based studies (RR = 1.31; 95% CI: 1.06-1.61; P = 0.010) and in subjects below 60 years old (RR = 1.28; 95% CI: 1.07-1.54; P = 0.060).

CONCLUSION

our systematic review and meta-analysis showed that a low serum vitamin D level was indeed associated with an increased risk of VTE.

Are serum vitamin D, calcium and phosphorous associated with restless leg syndrome? A systematic review and meta-analysis

BACKGROUND

It is hypothesized that vitamin D deficiency, and calcium/phosphate imbalance could be involved in the pathophysiology of restless leg syndrome (RLS). This systematic review and meta-analysis of observational studies were carried out to reach a firm conclusion regarding the possible association between vitamin D, calcium and phosphorous levels with RLS in end-stage renal disease (ESRD) patients, other comorbidities and healthy population.

METHODS

PubMed, Scopus, ISI Web of Science, and Cochrane's library were systematically searched up to June 2020. Quality assessment of the included observational studies was performed using Newcastle-Ottawa Quality Assessment Scale. Statistical analyses were done using STATA 11.2. A P-value <0.05 were considered statistically significant.

RESULTS

A total of 36 studies involving 9590 participants were included in this systematic review and meta-analysis. We found that serum vitamin D level is significantly lower (WMD -3.39 ng/mL; 95% CI, -5.96 to -0.81; P = 0.010; I² = 86.2%) and phosphorous (SMD 0.19; 95% CI, 0.04-0.34; P = 0.011; I² = 83.6%) is significantly higher in RLS individuals compared to the non-RLS individuals. However, the mean difference of serum calcium was not significant in comparison between RLS and control groups (SMD -0.01; 95% CI, -0.19 to 0.18; P = 0.957; I² = 89.2%).

CONCLUSION

Results revealed a significant association between serum vitamin D and phosphorous with RLS. However, further prospective cohort studies and clinical trials are needed for better understanding of the relationship between these variables.

Vitamin D Provides Benefit Based on the Proinflammatory Effects of Homocysteine in Elderly Patients With Type 2 Diabetes Mellitus

PURPOSE

It is unclear whether vitamin D provides any benefit against the pro-inflammatory effects of homocysteine in elderly patients with type 2 diabetes mellitus (T2DM).

METHODS

We compared lymphocyte counts for CD3, CD19, CD4, and CD8 subsets between elderly (age ≥65 years) T2DM patients (n = 5098) and nondiabetes control subjects (n = 20,590) based on the serum concentrations of homocysteine and total vitamin D (calcidiol + calcifediol [total vitamin D, TVD]; <20, 20-30, and >30 ng/mL).

FINDINGS

Significant variation in CD19 (P = 0.019), CD4 (P = 0.015), and CD8 (P < 0.001) were associated with serum TVD in T2DM patients with homocysteine ≤15 μmol/L, whereas CD3 (P = 0.003) and CD8 (P = 0.019) varied in control subjects with homocysteine ≤15 μmol/L. In T2DM patients with high homocysteine (>15 μmol/L) levels, significant variation based on serum TVD occurred in CD19 only (P = 0.024), whereas CD3 (P = 0.016) and CD4 (P = 0.001) varied in control subjects with high homocysteine concentrations.

IMPLICATIONS

Serum TVD influences variation in CD3, CD19, CD4, and CD8 lymphocyte subsets based on the serum homocysteine concentration in elderly T2DM patients and nondiabetic individuals with moderate to high homocysteine concentrations. The effect of TVD is partially attenuated in individuals with high homocysteine concentrations, with greater attenuation occurring in patients with T2DM. Differences in the variation of lymphocyte subsets between nondiabetes subjects with moderate homocysteine concentrations and those with high homocysteine concentrations constitute a shift from CD8-positive cells to CD4-positive cells, suggesting a change in TH1/TH2 balance based on TVD and homocysteine concentrations that is absent in diabetes cases with high homocysteine concentrations.

Lower levels of vitamin D are associated with SARS-CoV-2 infection and mortality in the Indian population: An observational study

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Differential distributions of vitamin D were observed in the Indian population.

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Vitamin D levels was inversely correlated with SARS-CoV-2 infection rate.

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COVID-19 mortality rate was negatively associated with mean vitamin D levels.

Background

The role of vitamin D in the susceptibility and severity of various viral diseases has been well documented. Recently, some reports highlighted the possible importance of vitamin D in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Although India receives adequate sunlight throughout the year, the majority of Indians are deficient in vitamin D levels. In the present study, we hypothesized that vitamin D deficiency would be associated with the SARS-CoV-2 infection rate and mortality in the Indian population.

Materials and methods

SARS-CoV-2 infection and mortality data were obtained from the Government of India's official website (accessed on 16th August 2020). Various literature databases like PubMed and Google Scholar were searched to find the mean of 25-hydroxyvitamin D [25(OH)D] levels in different states and union territories of India, Pearson correlation was carried out to investigate the possible link between mean 25(OH)D levels and SARS-CoV-2 infection and mortality per million of the population.

Results

An inverse correlation was observed between the mean level of 25(OH)D and SARS-CoV-2 infection rate (r = −0.43, p = 0.02) and mortality rate (r = −0.42, p = 0.02).

Conclusions

The present observational study revealed an association of vitamin D with SARS-CoV-2 infection and related mortality. Further studies are required to validate our observations.

A comprehensive genetic and epidemiological association analysis of vitamin D with common diseases/traits in the UK Biobank

Vitamin D has been intensively studied for its association with human health, but the scope of such association and the causal role of vitamin D remain controversial. We aim to comprehensively investigate the links between vitamin D and human health through both epidemiological and Mendelian randomization (MR) analyses. We examined the epidemiological associations between serum 25-hydroxyvitamin D (25(OH)D) concentration and 90 diseases/traits in 326,409 UK Biobank (UKBB) Europeans. The causal relations between 25(OH)D and 106 diseases/traits were investigated by performing MR analysis using genome-wide significant 25(OH)D-associated variants (N = 143) from the largest UKBB GWAS to date. In epidemiological analysis, we found 25(OH)D was associated with 45 diseases/traits across cardiovascular/metabolic diseases, psychiatric/neurological diseases, autoimmune/inflammatory diseases, cancer, musculoskeletal diseases, and quantitative traits. In MR-analysis, we presented evidence suggesting potential causal role of 25(OH)D in increasing height (β = .064, 95% confidence interval [CI] = 0.019-0.11) and preventing the risk of ovarian cancer (odds ratio [OR] = 0.96, 95% CI = 0.93-0.99), multiple sclerosis (OR = 0.96, 95% CI = 0.94-0.98), leg fracture (OR = 0.60, 95% CI = 0.45-0.80) and femur fracture (OR = 0.53, 95% CI = 0.32-0.84). These findings confirmed associations of vitamin D with a broad spectrum of diseases/traits and supported the potential causal role of vitamin D in promoting health.

Serum 25-hydroxyvitamin D concentration and its association with glucose intolerance in an indigenous population

BACKGROUND AND AIMS

Type 2 diabetes is a multifactorial disease resulting from diverse genetic and environmental factors as well as the interaction between them. Low levels of 25-hydroxyvitamin D [25(OH)D], an indicator of vitamin D status, have been associated with an increased risk of type 2 diabetes, but not consistently. Also, it remains to be determined if this association differs among ethnic groups. Therefore, we aimed to evaluate vitamin D status and its association with glucose intolerance in a Brazilian indigenous population, the Xavante Indians.

METHODS

The study population consisted of 819 full Xavante Indians (410 women), aged ≥18 years and living in two indigenous reserves located in Mato Grosso State, central region of Brazil. Clinical examination and anthropometrical measurements were made, blood samples were obtained for total cholesterol, HDL-cholesterol, triglycerides and 25(OH)D measurement. Fasting and 2-h post 75 g oral glucose load capillary glucose was measured. Vitamin D status was defined by serum 25(OH)D levels: vitamin D sufficiency (25(OH)D: 30-100 ng/mL), vitamin D insufficiency (25(OH)D: 20- <30 ng/mL) and vitamin D deficiency (25(OH)D: < 20 ng/mL). Multiple logistic regression was performed to identify independent associations between 25(OH)D levels and impaired glucose tolerance or diabetes mellitus.

RESULTS

Analyses stratified by 25(OH)D levels shows that 65.5% of the population had vitamin D deficiency/insufficiency (25(OH)D < 30 ng/mL). 25(OH)D concentrations were lower in individuals with impaired glucose tolerance or diabetes mellitus than in normal glucose tolerant individuals. Multiple logistic regression analysis showed an inverse association between increments of 25(OH)D and presence of diabetes mellitus (OR per 1 ng/mL increase in 25(OH)D: 0.97; 95% confidence interval: 0.95-0.99), or impaired glucose tolerance (OR per 1 ng/mL increase in 25(OH)D: 0.87; 95% confidence interval: 0.85-0.89), in an age, sex, BMI and season of sampling-adjusted model.

CONCLUSIONS

The present population-based study found a high prevalence of hypovitaminosis D among Xavante Indians. In this at-risk population of type 2 diabetes, a significant association of higher serum 25(OH)D with a decreased prevalence of diabetes mellitus and impaired glucose tolerance was observed.

Vitamin D and Cardiovascular Disease, with Emphasis on Hypertension, Atherosclerosis, and Heart Failure

Vitamin D deficiency is the most common nutritional deficiency, affecting almost one billion people worldwide. Vitamin D is mostly known for its role in intestinal calcium absorption and bone mineralization. However, the observation of seasonal changes in blood pressure and the subsequent identification of vitamin D receptor (VDR) and 1α-hydroxylase in cardiomyocytes, as well as endothelial and vascular smooth muscle cells, implicated a role of vitamin D in the cardiovascular system. Animal studies provided compelling evidence that vitamin D signaling is essential for cardiovascular integrity, especially for the regulation of vascular tone and as an antifibrotic and antihypertrophic signaling pathway in the heart. In addition, observational studies reported an association between vitamin D deficiency and risk of hypertension, atherosclerosis, and heart failure. However, recent clinical intervention studies failed to prove the causal relationship between vitamin D supplementation and beneficial effects on cardiovascular health. In this review, we aim to highlight our current understanding of the role of vitamin D in the cardiovascular system and to find potential explanations for the large discrepancies between the outcome of experimental studies and clinical intervention trials.