High Prevalence of Vitamin D Deficiency and Correlation of Serum Vitamin D with Cardiovascular Risk in Patients with Metabolic Syndrome

Association of serum vitamin D and the risk of cardiovascular diseases among diabetic patients: A systematic review and meta-analysis

BACKGROUND

The emerging role of vitamin D has drawn the attention of researchers around the world, including its involvement in cardiovascular complications among individuals with diabetes.

AIM

This study aimed to obtain comprehensive evidence on the association between serum vitamin D level and the risk of cardiovascular disease among patients with diabetes.

METHODS

Systematic search was performed on July 1st, 2023, to identify and screen published literature reporting the association between vitamin D and cardiovascular disease among diabetic patients in six databases. Each eligible study was appraised for its quality using modified Newcastle Ottawa Scale for cross-sectional and cohort studies. Meta-analysis was performed using Dersimonian-Laird random effect model or fix-effect model. The heterogeneity and publication bias were judged based on percentage of I2 and the symmetry of Begg's funnel plot, respectively.

RESULTS

As many as 22 studies were found eligible for the systematic review. A meta-analysis from 13 studies comprising of 3850 and 1797 (control and exposure groups, respectively) revealed that serum vitamin D level was significantly lower in patients with diabetes and cardiovascular diseases (Z = 4.89; p-total<0.001; SMD = 0.68 [95%CI: 0.41-0.95]), yet the heterogeneity was high. Following the adjustment of removing the potential outliers, the same results were still observed (Z = 6.19; p-total<0.001; SMD = 0.35 [95%CI: 0.24-0.46]). Though decreased, high heterogeneity could not be resolved, resulting in moderate level of this evidence. Another pooled analysis of 7 studies with 4211 patients in control group and 2381 patients in exposure group revealed that lower level of serum vitamin D is a risk factor for cardiovascular disease incidence among diabetic patients (Z = 4.89; p-total<0.001; OR: 1.76 [95%CI: 1.4-2.2]).

CONCLUSION

Serum vitamin D level status is a risk factor for developing cardiovascular diseases among diabetic patients, hence should be carefully monitored and maintained.

PROSPERO REGISTRATION

CRD42023437698.

Telmisartan ameliorates nephropathy and restores the hippo pathway in rats with metabolic syndrome

The main objective of this study was to determine if the telmisartan-ameliorative effects of metabolic syndrome (MetS)-evoked nephropathy are attributed to the Hippo pathway. A secondary objective was to investigate the potential of vitamin D3 to enhance telmisartan-favourable effects. A diet composed of 24% fat and 3% salt, along with drinking water containing 10% fructose, was administered for 12 weeks to induce MetS. MetS-rats were given telmisartan (5 mg/kg/day), vitamin D3 (10 μg/kg/day) or both by gavage, starting in the sixth week of experimental diet administration. Assessments performed at closure included renal function, histological examination, catalase, malondialdehyde (MDA), nuclear factor kappa-B (NF-κB), interleukin-6 (IL-6), peroxisome proliferator-activated receptor-γ (PPAR-γ), phosphatase and tensin homolog (PTEN), and transforming growth factor-β (TGF-β). Matrix metalloproteinase-9 (MMP-9) immunostaining was conducted. The expression of the Hippo pathway components, as well as that of angiotensin II type 1 and type 2 (AT1 and AT2), receptors was evaluated. Telmisartan attenuated MetS-evoked nephropathy, as demonstrated by improvement of renal function and histological features, enhancement of catalase, reduction of MDA, inflammation (NF-κB, IL-6), and renal fibrosis (increased PPAR-γ and PTEN and reduced MMP-9 and TGF-β). Telmisartan downregulated AT1-receptor, upregulated AT2-receptor and restored the Hippo pathway. Vitamin D3 replicated most of the telmisartan-elicited effects and enhanced the antifibrotic actions of telmisartan. The alleviative effects of telmisartan on MetS-evoked nephropathy may be related to the restoration of the Hippo pathway. The combination of vitamin D3 and telmisartan exerted more favourable effects on metabolic and nephropathic biomarkers compared with either one administered alone.

Vitamin D and the Metabolic Phenotype in Weight Loss After Bariatric Surgery: A Longitudinal Study

PURPOSE

To evaluate the influence of vitamin D (VD) concentrations coupled with metabolic phenotypes preoperatively and 6 months after Roux-en-Y gastric bypass (RYGB) on body variables and weight loss.

MATERIALS AND METHODS

A longitudinal, retrospective, analytical study comprising 30 adult individuals assessed preoperatively (T0) and 6 months (T1) after undergoing Roux-en-Y gastric bypass. The participants were distributed preoperatively into metabolically healthy obese (MHO) and metabolically unhealthy obese individuals (MUHO) according to the HOMA-IR classification, as well as the adequacy and inadequacy of vitamin D concentrations in the form of 25(OH)D. All participants were assessed for weight, height, body mass index (BMI), waist circumference (WC), waist-to-height ratio (WHtR), visceral adiposity index (VAI), body circularity index (BCI), body adiposity index (BAI), weight loss, and assessment of 25(OH)D and 1,25(OH)2D concentrations using high-performance liquid chromatography with an ultraviolet detector (HPLC-UV). The statistical program used was SPSS version 21.

RESULTS

VD adequacy and a healthy phenotype in the preoperative period may play an important role concerning body fat distribution, as the body averages for WHtR (0.020*) and BCI (0.020*) were lower in MHO participants. In comparison, those with VD inadequacy and MUHOs had higher BAI averages (0.000*) in the postoperative period. Furthermore, it is possible that VD inadequacy before and after RYGB, even in the presence of an unhealthy phenotype, may contribute to the increase in VAI values (0.029*) after this surgery. Only those with inadequate VD and MUHOs had higher 25(OH)D concentrations. Besides, this unhealthy phenotype had a greater reduction in BMI in the early postoperative period (p < 0.001).

CONCLUSION

This study suggests that VD adequacy and the presence of a healthy phenotype appear to have a positive impact on the reduction of visceral fat in the context of pre- and postoperative obesity. In addition, there was a greater weight reduction in those with VD inadequacy and in MUHO, which suggests that the volumetric dilution effect of VD and catabolism after bariatric surgery is more pronounced in this specific metabolic phenotype.

Mechanisms and risk factors of metabolic syndrome in children and adolescents

Metabolic syndrome (MetS) is a complex disorder characterized by abdominal obesity, elevated blood pressure, hyperlipidemia, and elevated fasting blood glucose levels. The diagnostic criteria for MetS in adults are well-established, but there is currently no consensus on the definition in children and adolescents. The etiology of MetS is believed to involve a complex interplay between genetic predisposition and environmental factors. While genetic predisposition explains only a small part of MetS pathogenesis, modifiable environmental risk factors play a significant role. Factors such as maternal weight during pregnancy, children's lifestyle, sedentariness, high-fat diet, fructose and branched-chain amino acid consumption, vitamin D deficiency, and sleep disturbances contribute to the development of MetS. Early identification and treatment of MetS in children and adolescents is crucial to prevent the development of chronic diseases later in life. In this review we discuss the latest research on factors contributing to the pathogenesis of MetS in children, focusing on non-modifiable and modifiable risk factors, including genetics, dysbiosis and chronic low-grade inflammation.

Association of Vitamin D Deficiency and Insufficiency with Pathology in Hospitalized Patients

Vitamin D deficiency is one of the most common medical conditions, with approximately one billion people having low vitamin D levels. Vitamin D is associated with a pleiotropic effect (immunomodulatory, anti-inflammatory and antiviral), which can be essential for a better immune response. The aim of this research was to evaluate the prevalence of vitamin D deficiency/insufficiency in hospitalized patients focusing on demographic parameters as well as assessing the possibility of its associations with different comorbidities. Of 11,182 Romanian patients evaluated in the study over 2 years, 28.83% had vitamin D deficiency, 32.11% insufficiency and 39.05% had optimal vitamin D levels. The vitamin D deficiency was associated with cardiovascular disorders, malignancies, dysmetabolic disorders and SARS-CoV2 infection, older age and the male sex. Vitamin D deficiency was prevalent and showed pathology association, while insufficiency of vitamin D (20-30 ng/mL) had lower statistical relevance and represents a grey zone in vitamin D status. Guidelines and recommendations are necessary for homogeneity of the monitoring and management of inadequately vitamin D status in the risk categories.

Obesity-Associated Vitamin D Deficiency Correlates with Adipose Tissue DNA Hypomethylation, Inflammation, and Vascular Dysfunction

Vitamin D (VD) deficiency is a hallmark of obesity and vascular dysfunction. We sought to test the hypothesis that VD deficiency may contribute to obesity-related vascular dysfunction by inducing adipokine hypomethylation and augmented expression. To this end, we collected blood and adipose tissues (ATs) from a cohort of 77 obese participants who were classified as having mild, moderate, or severe VD deficiency. The body composition, vascular reactivity, cardiometabolic profiles, and DNA methylation of 94 inflammation-related adipokines were measured. Our results show that higher degrees of VD deficiency were associated with lower DNA methylation and induced the expression of inflammatory adipokines such as B-cell lymphoma 6 (BCL6), C-X-C Motif Chemokine Ligand 8 (CXCL8), histone deacetylase 5 (HDAC5), interleukin 12A (IL12A), and nuclear factor κB (NFκB) in the ATs. They were also associated with higher BMI and total and visceral fat mass, impaired insulin sensitivity and lipid profiles, AT hypoxia, and higher concentrations of circulating inflammatory markers. Moderate and severe VD deficiency correlated with impaired vasoreactivity of the brachial artery and AT-isolated arterioles, reduced nitric oxide generation, and increased arterial stiffness. In a multivariate regression analysis, the VD deficiency level strongly predicted the adipokine methylation score, systemic inflammation, and microvascular dysfunction. In conclusion, our findings suggest that VD deficiency is a possible contributor to obesity-related adipokine hypomethylation, inflammation, and vascular dysfunction.

Effect of vitamin D levels on the hormonal and metabolic status in patients with metabolic syndrome and chronic kidney disease

Aim. To assess the association of vitamin D deficiency with hormonal and metabolic disorders, including with insulin resistance and leptin levels, in patients with metabolic syndrome (MS) and chronic kidney disease (CKD).

Material and methods. The study included 81 patients with MS and CKD aged 45-59 years (mean age, 51±4 years). Depending on vitamin D level, the patients were divided into two groups: group 1 (n=49) — patients with reduced level (23,2±5,1 ng/ml); group 2 (n=32) — patients with an adequate level (54,8±12,1 ng/ml). Statistical processing was carried out using STATISTICA 10.0 software.

Results. In patients of the first group, the following parameters were higher than in the second one: waist circumference by 9,0% (p<0,05), waist-to-hip ratio by 8,2% (p<0,05), body mass index by 15,1% (p<0,05). The groups did not differ significantly in systolic and diastolic blood pressure levels. In the first group, the level of total cholesterol by 18,6% (p<0,01), low density lipoprotein cholesterol by 11,9% (p<0,05), triglycerides by 20,8% (p<0,01), Homeostasis Model Assessment Insulin Resistance (HOMA-IR) by 42,5% (p<0,001), leptin by 30,5% (p<0,01) were higher than in the second group. More severe left ventricular diastolic dysfunction in the first group than in the second one was determined as follows: lower left ventricular early to late filling (E/A) by 13,2% (p<0,05) and deceleration time of the early transmitral flow velocity by 13,1% (p<0,05).

Conclusion. The results obtained indicate that patients with MS, CKD and vitamin D deficiency are more likely to have general obesity, more pronounced carbohydrate (HOMA-IR index) and fat (levels of total cholesterol, low-density lipoprotein cholesterol, triglycerides) metabolism disorders, as well as high serum levels of leptin compared with patients with adequate levels of this vitamin.

Consumption of pistachio nuts positively affects lipid profiles: A systematic review and meta-analysis of randomized controlled trials

We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) to evaluate the effects of consuming pistachio nuts on lipid profiles (total cholesterol [TC], low-density lipoprotein cholesterol [LDL-C], high-density lipoprotein cholesterol [HDL-C], and triglyceride [TG]). Databases of PubMed, Scopus, ISI Web of Science, and Cochrane Library were searched from inception to June 2019 to identify RCTs documenting the effects of consuming pistachio nuts on blood lipid profiles in adults. Effect sizes were reported as weighted mean difference (WMD) and 95% confidence interval (CI) using the random-effects models (DerSimonian-Laird method). Twelve eligible RCTs were included. Consumption of pistachio nuts decreased TC (WMD: -7.48 mg/dL; 95% CI, -12.62 to -2.34), LDL-C (WMD: -3.82 mg/dL; 95% CI, -5.49 to -2.16) and TG (WMD: -11.19 mg/dL; 95% CI, -14.21 to -8.17) levels. However, HDL-cholesterol levels (WMD: 2.45 mg/dL; 95% CI, -2.44 to 7.33) did not change following pistachio consumption. Consuming pistachio nuts may improve lipid profiles (TC, LDL-C, TG) in adults and may be protective against cardiometabolic diseases. However, further studies with larger sample sizes are required to confirm these results.

Nutritional Supplementation of Naturally Occurring Vitamin D to Improve Hemorrhagic Stroke Outcomes

Vitamin D deficiency, if left untreated, is associated with bone disorders, cardiovascular damage, and an increased risk of ischemic stroke. While there are various nutritional options for the natural intake of vitamin D, we hope to elucidate the potential mechanisms dietary vitamin D may play in hemorrhagic stroke pathology. This scoping review outlines findings from studies relevant to the biochemical activity of vitamin D, the impact of vitamin D deficiency on hemorrhagic stroke outcomes, and the potential benefit of nutritional vitamin D on hemorrhagic stroke outcomes. Here, we analyze the relevant factors that can lead to vitamin D deficiency, and subsequently, a higher risk of hemorrhagic stroke incidence with worsened subsequent outcomes. The neuroprotective mechanisms through which vitamin D works to attenuate hemorrhagic stroke onset and post-stroke outcomes have not yet been thoroughly examined. However, researchers have proposed several potential protective mechanisms, including reduction of blood brain barrier disturbance by inhibiting the production of reactive oxygen species, mitigation of inflammation through a reduction of levels of proinflammatory cytokines, and prevention of cerebral vasospasm and delayed cerebral ischemia following subarachnoid hemorrhage and intracerebral hemorrhage. While more research is needed and there are limitations to vitamin D supplementation, vitamin D as a whole may play a significant role in the dynamics of hemorrhagic stroke. Further research should focus on expanding our understanding of the neuroprotective capacity and mechanisms of vitamin D, as well as how vitamin D supplementation could serve as an effective course of treatment of hemorrhagic strokes.

Machine learning approaches to constructing predictive models of vitamin D deficiency in a hypertensive population: a comparative study

Objective: Given the association between vitamin D deficiency and risk for cardiovascular disease, we used machine learning approaches to establish a model to predict the probability of deficiency. Determination of serum levels of 25-hydroxy vitamin D (25(OH)D) provided the best assessment of vitamin D status, but such tests are not always widely available or feasible. Thus, our study established predictive models with high sensitivity to identify patients either unlikely to have vitamin D deficiency or who should undergo 25(OH)D testing.Methods: We collected data from 1002 hypertensive patients from a Spanish university hospital. The elastic net regularization approach was applied to reduce the dimensionality of the dataset. The issue of determining vitamin D status was addressed as a classification problem; thus, the following classifiers were applied: logistic regression, support vector machine (SVM), random forest, naive Bayes, and Extreme Gradient Boost methods. Classification accuracy, sensitivity, specificity, and predictive values were computed to assess the performance of each method.Results: The SVM-based method with radial kernel performed better than the other algorithms in terms of sensitivity (98%), negative predictive value (71%), and classification accuracy (73%).Conclusion: The combination of a feature-selection method such as elastic net regularization and a classification approach produced well-fitted models. The SVM approach yielded better predictions than the other algorithms. This combination approach allowed us to develop a predictive model with high sensitivity but low specificity, to identify the population that could benefit from laboratory determination of serum levels of 25(OH)D.

Vitamin D and Stroke: Effects on Incidence, Severity, and Outcome and the Potential Benefits of Supplementation

Vitamin D serum level has been positively associated with improved cardiovascular health, especially with reduction of stroke risk. This systemic review summarizes and synthesizes findings from studies relevant to the relationship between vitamin D and stroke risk, severity, and outcome; potential mechanisms explaining such a relationship; and outcomes from vitamin D supplementation. The literature shows that vitamin D deficiency is a significant risk factor for ischemic stroke, with sun exposure, sex, age, race, diabetes, and genetics playing a role as well. Stroke severity and short- and long-term outcomes also worsen with vitamin D deficiency. The neuroprotective mechanisms by which vitamin D operates to mitigate stroke onset and outcomes have yet to be fully studied, but researchers have proposed several pathways, including promotion of certain neuroprotective growth factors, reduction of arterial pressure through vasodilation, and inhibition of reactive oxygen species. There is some evidence that vitamin D supplementation could lower stroke risk and improve recovery, though outcomes can also be negligible or negative. Although results are mixed and the limitations of vitamin D supplementation merit some caution, vitamin D overall plays a significant role in stroke health. Future research should further develop understanding of the neuroprotective mechanisms of vitamin D and study how supplementation could be administered effectively in stroke treatment.

Logistic LASSO and Elastic Net to Characterize Vitamin D Deficiency in a Hypertensive Obese Population

Aim: The primary objective of our research was to compare the performance of data analysis to predict vitamin D deficiency using three different regression approaches and to evaluate the usefulness of incorporating machine learning algorithms into the data analysis in a clinical setting. Methods: We included 221 patients from our hypertension unit, whose data were collected from electronic records dated between 2006 and 2017. We used classical stepwise logistic regression, and two machine learning methods [least absolute shrinkage and selection operator (LASSO) and elastic net]. We assessed the performance of these three algorithms in terms of sensitivity, specificity, misclassification error, and area under the curve (AUC). Results: LASSO and elastic net regression performed better than logistic regression in terms of AUC, which was significantly better in both penalized methods, with AUC = 0.76 and AUC = 0.74 for elastic net and LASSO, respectively, than in logistic regression, with AUC = 0.64. In terms of misclassification rate, elastic net (18%) outperformed LASSO (22%) and logistic regression (25%). Conclusion: Compared with a classical logistic regression approach, penalized methods were found to have better performance in predicting vitamin D deficiency. The use of machine learning algorithms such as LASSO and elastic net may significantly improve the prediction of vitamin D deficiency in a hypertensive obese population.

The Use of Nutraceuticals to Counteract Atherosclerosis: The Role of the Notch Pathway

Despite the currently available pharmacotherapies, today, thirty percent of worldwide deaths are due to cardiovascular diseases (CVDs), whose primary cause is atherosclerosis, an inflammatory disorder characterized by the buildup of lipid deposits on the inside of arteries. Multiple cellular signaling pathways have been shown to be involved in the processes underlying atherosclerosis, and evidence has been accumulating for the crucial role of Notch receptors in regulating the functions of the diverse cell types involved in atherosclerosis onset and progression. Several classes of nutraceuticals have potential benefits for the prevention and treatment of atherosclerosis and CVDs, some of which could in part be due to their ability to modulate the Notch pathway. In this review, we summarize the current state of knowledge on the role of Notch in vascular health and its modulation by nutraceuticals for the prevention of atherosclerosis and/or treatment of related CVDs.

Avaliação da frequência de deficiência de vitamina D em pacientes com obesidade

Introdução: A obesidade é um problema de saúde pública mundial. Além das diversas alterações metabólicas encontradas em indivíduos obesos, há evidências de alterações no sistema endócrino, como observado no metabolismo da vitamina D.Objetivos:Avaliar a frequência de deficiência de vitamina D em uma amostra de pacientes adultos com obesidade.Materiais e métodos: Foi realizado um estudo transversal retrospectivo analisando 183 prontuários dos pacientes atendidos pela primeira vez buscando tratamento para obesidade. Após os fatores de exclusão, restaram 113 prontuários válidos.Resultados: O IMC variou de 30.1 a 77.1, com uma mediana de 44.5 kg/m2. Trinta pacientes (26,55 %) tinham a Vitamina D abaixo de 20 ng/ml, sendo considerados com diagnóstico de Deficiência de Vitamina D. Nenhum correlação foi encontrada entre os níveis de Vitamina D e os parâmetros antropométricos. Houve associação significativa estatística dos níveis de Vitamina D com colesterol total (r=-0.26; p=0.0053), LDL-colesterol (r=-0.25; p=0.0071), além de uma tendência à significância com os níveis de TGP (r=0.16; p=0.088).Conclusão: Houve uma elevada frequência de deficiência de vitamina D em pacientes obesos. Não houve correlação entre os níveis de vitamina D e os marcadores antropométricos, porém foi encontrada uma correlação inversa de vitamina D com níveis de colesterol total e LDL-colesterol, mostrando a relação com a dislipidemia. Também, houve uma tendência à significância com os níveis de TGP, o que provavelmente remete à esteatose hepática, comum em obesos.

Effects of grape products on blood lipids: a systematic review and dose–response meta-analysis of randomized controlled trials

Grape products through several plausible mechanisms-of-action are reported to improve lipid profile. The present systematic review revealed that grape product supplementation might have a positive effect on achieving a lipid profile target.

Association between serum 25-hydroxyvitamin D, hemoglobin A1c and fasting blood glucose levels in adults with diabetes mellitus

In the present study, the aim was to investigate the association between serum 25-hydroxyvitamin D concentration and measures of glycemic control including hemoglobin A1c (HbA1c) and fasting blood glucose (FBG) in adult patients with diabetes mellitus (DM) from the north of Jordan. Another aim was to compare serum levels of 25-hydroxyvitamin D between patients with good glycemic control and patients with uncontrolled DM. This was a cross-sectional study that included 261 participants with DM. The concentration of 25-hydroxyvitamin D was measured using electrochemiluminescence immunoassay, HbA1c was measured using turbidimetric inhibition immunoassay and FBG was measured using the hexokinase method. Data regarding other clinical variables were obtained from medical records or by self-reporting. Participants with good glycemic control exhibited significantly higher levels of 25-hydroxyvitamin D compared with participants with uncontrolled DM (P=0.03). Participants with sufficient vitamin D status (>30 ng/ml in serum) exhibited significantly lower HbA1c level compared with participants with deficient vitamin D (<20 ng/ml) status (P=0.02). Correlation analysis determined significant inverse correlations between 25-hydroxyvitamin D levels and HbA1c and FBG levels (r=-0.23 and -0.17, respectively, both P<0.01). There were also significant correlations between duration of DM and HbA1c and FBG levels (both r=0.21, P<0.01). HbA1c level was also inversely correlated with participants' age (r=-0.19, P<0.01). Further multiple linear regression analysis revealed an inverse significant association between HbA1c and 25-hydroxyvitamin D levels (F=12.95, R²=0.48, P<0.01) but did not identify a similar association between FBG and 25-hydroxyvitamin D levels. These findings may encourage further research to identify if vitamin D supplementation may improve measures of glycemic control, and how vitamin D may affect glucose homeostasis in patients with DM.

The association between the serum level of vitamin D and ischemic heart disease: a study from Jordan

Background

Decreased levels of vitamin D were associated with increased risk of multiple diseases, including cardiovascular diseases. However, there seem to be some discrepancies among the results obtained from different studies. The aim of the present study was to explore the importance of having sufficient serum levels of vitamin D in reducing the incidence and the progression of coronary artery stenosis and ischemic heart disease (IHD).

Methods

Serum levels of vitamin D were measured using radioimmunoassay in 186 Jordanian patients who underwent investigative coronary catheterization. Of these patients, 133 were suffering from coronary artery stenosis. The association between vitamin D levels, coronary stenosis and many risk factors was determined using SPSS software.

Results and conclusions

Interestingly, the current results did not show an association between vitamin D abnormalities and the incidence or the reoccurrence of coronary artery stenosis. Moreover, significant differences were detected in the prevalence of vitamin D abnormalities based on the patient’s gender, and there was a significant association between vitamin D abnormalities and both body mass index and dyslipidemia. However, current results did not show any significant association with other risk factors for IHD. For instance, no association was found with smoking, hypertension, diabetes mellitus, stable and unstable angina or with acute recent myocardial infarction.

Association of vitamin D status with metabolic syndrome and its components: A cross-sectional study in a population of high educated Iranian adults

AIM

We aimed to assess the association of vitamin D status with metabolic syndrome and its components among high educated Iranian adults.

METHOD

In this cross-sectional study, 352 faculty members with age of 35 years or more, belong to Tarbiat Modares University, Tehran, Islamic Republic of Iran, were recruited during 2016 and 2017. Fasting blood samples were obtained to quantify serum 25(OH)D concentrations, glycemic indicators and lipid profile. Metabolic syndrome was defined based on the guidelines of the National Cholesterol Education Program Adult Treatment Panel III (ATP III). Multivariate logistic regression adjusted for potential confounders was used to evaluate the association between vitamin D status and metabolic syndrome.

RESULT

Metabolic syndrome and vitamin D insufficiency were prevalent among 26% and 60.2% of subjects, respectively. There was no statistically significant difference in the prevalence of metabolic syndrome across quartiles of 25(OH)D levels either before or after adjusting for potential confounders (OR: 0.94, 95% CI: 0.43-1.95). In terms of metabolic syndrome components, subjects in the highest quartile of vitamin D levels had 59% decreased risk of abdominal obesity compared with those in the lowest quartile (OR: 0.41, 95% CI: 0.17-0.99), after adjusting for potential confounders. Such inverse relationship was also seen for elevated blood pressure (OR: 0.37, 95% CI: 0.14-0.99), and abnormal glucose homeostasis (OR: 0.40, 95% CI: 0.19-0.85).

CONCLUSION

Serum levels of 25(OH)D was inversely associated with the risk of abdominal obesity, hypertension, and abnormal glucose homeostasis. However, no significant relationship was seen for metabolic syndrome.

Association of parathyroid hormone and vitamin D with untreated hypertension: Is it different in white-coat or sustained hypertension?

BACKGROUND

Previous reports about the relationship between a high parathyroid hormone (PTH) and low vitamin D levels with blood pressure in different hypertension groups are conflicting.

OBJECTIVE

We studied serum PTH and vitamin D levels in white-coat (WCHT) and sustained hypertension (SHT) patients who had not been on antihypertensive treatment. We also investigated the association between serum PTH and vitamin D levels with respect to blood pressure in SHT and WCHT patients.

METHODS

We included 52 SHT patients (54.06 ± 9.2 years, 32 newly diagnosed and 20 previously diagnosed with SHT who had not been treated with antihypertensive medication for 3 months or more), 48 WCHT patients (53.64 ± 9.5 years), and 50 normotensive (NT) healthy controls (53.44 ± 8.4 years) in our study. In addition to routine tests, PTH and vitamin D levels were measured.

RESULTS

Serum PTH levels were significantly higher in SHT patients not taking antihypertensive medications than in WCHT patients and NT controls (p = 0.004). Although PTH levels were higher in WCHT than in NT groups, the difference was not statistically significant. In SHT patients, PTH levels showed a positive correlation with office systolic (r = 0.363, p = 0.008), office diastolic (r = 0.282, p = 0.038), home systolic (r = 0.390, p = 0.004), and home diastolic blood pressures (r = 0.397, p = 0.003). Serum vitamin D levels were similar in SHT, WCHT and NT groups. Vitamin D levels were not associated with blood pressures in the entire study group. Furthermore, no significant relation was found between vitamin D and PTH levels in SHT and WCHT groups.

CONCLUSION

PTH levels are significantly higher in untreated SHT patients than WCHT patients and NT subjects. However, vitamin D levels are similar in SHT, WCHT and NT groups. There is a significant association between PTH levels and blood pressures suggesting PTH has a role in increase of blood pressure in SHT.

No effect of vitamin D supplementation on cardiovascular risk factors in subjects with metabolic syndrome: a pilot randomised study

Introduction

Patients with metabolic syndrome (MetS) may have lower 25-hydroxyvitamin D (25(OH)VitD) serum levels compared with non-MetS individuals. Vitamin D (VitD) deficiency is associated with various cardiovascular disease (CVD) risk factors. Yet, the effect of VitD supplementation on MetS remains uncertain. Our aim was to examine the effect of VitD supplementation on CVD risk factors in MetS subjects.

Material and methods

This pilot study had a PROBE (prospective, randomised, open-label, blinded end-point) design. Fifty patients with MetS were included and randomised either to dietary instructions (n = 25) (control group) or dietary instructions plus VitD 2000 IU/day (n = 25) (VitD group) for 3 months. This study is registered in ClinicalTrials.gov (NCT01237769).

Results

In both groups a similar small weight reduction was achieved. In the VitD group serum 25(OH)VitD levels significantly increased by 91% (from 16.0 (3.0–35.0) to 30.6 (8.4–67.0) ng/ml, p < 0.001), while in the control group no significant change was observed (from 10.0 (4.0–39.6) to 13.0 (3.5–37.0) ng/ml). In both groups triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, fasting glucose, haemoglobin A_1c, homeostasis model assessment index and diastolic blood pressure did not significantly change. Systolic blood pressure decreased by 3.7% (from 134 ±14 to 129 ±13 mm Hg, p = 0.05) in the VitD group, while it decreased by 1.5% (from 132 ±13 to 130 ±16 mm Hg, p = NS) in the control group (p = NS between groups). In the VitD group serum 25(OH)VitD increase was negatively correlated with SBP decrease (r = –0.398, p = 0.049).

Conclusions

VitD supplementation (2000 IU/day) did not affect various CVD risk factors in patients with MetS.