Role of vitamin D in cardiovascular health

Optimised liquid chromatography tandem mass spectrometry method for the simultaneous quantification of serum vitamin D analogues while also accounting for epimers and isobars

The accurate quantification of multiple vitamin D analogues simultaneously is challenging. This study set out to use liquid chromatography-tandem mass spectrometry (LC-MS/MS) to develop a method capable of measuring a comprehensive vitamin D profile, encompassing twelve vitamin D analogues (vitamin D2, D3, 25(OH)D2, 25(OH)D3, 1,25(OH)2D2, 1,25(OH)2D3, 24,25(OH)2D2, 24,25(OH)2D3, 3-epi-25(OH)D2, 3-epi-25(OH)D3, 7αC4 and1α(OH)D3) in a single run. Serum samples were prepared using double liquid-liquid extraction and analysed on an Agilent 6460 QQQ LC-MS/MS equipped with a Pursuit 3 Pentafluorophenyl (4.6 x 100 mm, 3 μm) column. Recovery rates for all analytes were above 95 % with a coefficient of variation (CV) below 10 %. The method exhibited good linearity (r > 0.995) and had a range of detection limits between 0.01 and 0.35 ng/mL and quantification limits between 0.15 and 0.96 ng/mL. Repeatability and within-lab precision were acceptable, with CV values below 10 % and 15 %, respectively. Method accuracy was excellent, with a systematic error below 6.60 %. additionally, all analytes-maintained stability for 48 h following sample preparation, and no interferences were observed among co-eluting analytes. Lastly, this method achieved "world-class" status according to the Sigma metric scale specifications, requiring minimal quality control to ensure data quality. This successfully validated method has the potential not only for improving vitamin D profiling procedures but also for aiding in the diagnosis of other genetic disorders where measuring beyond 25(OH)D is crucial.

Implementing micronutrient fortification programs as a potential practical contribution to achieving sustainable diets

Due to sustainability concerns related to current diets and environmental challenges, it is crucial to have sound policies to protect human and planetary health. It is proposed that sustainable diets will improve public health and food security and decrease the food system's effect on the environment. Micronutrient deficiencies are a well-known major public health concern. One-third to half of the world's population suffers from nutrient deficiencies, which have a negative impact on society in terms of unrealised potential and lost economic productivity. Large-scale fortification with different micronutrients has been found to be a useful strategy to improve public health. As a cost-effective strategy to improve micronutrient deficiency, this review explores the role of micronutrient fortification programmes in ensuring the nutritional quality (and affordability) of diets that are adjusted to help ensure environmental sustainability in the face of climate change, for example by replacing some animal-sourced foods with nutrient-dense, plant-sourced foods fortified with the micronutrients commonly supplied by animal-sourced foods. Additionally, micronutrient fortification considers food preferences based on the dimensions of a culturally sustainable diet. Thus, we conclude that investing in micronutrient fortification could play a significant role in preventing and controlling micronutrient deficiencies, improving diets and being environmentally, culturally and economically sustainable.

Associations of serum 25(OH)D levels with physical performance and anabolic hormones in young men

Purpose: The present study examined the association of vitamin D measured by serum 25(OH)D with physical performance outcomes and serum levels of anabolic hormones in young men. Methods: 412 young men (age 19 ± 1 year) entering their compulsory military service volunteered to participate in the study. The study consisted of two groups from two different military bases: Group A was studied in January and group B in July. The groups were first compared with each other and due to statistically significant (p < 0.001 analyzed with independent samples t-test) differences in physical condition (sit-up, push-up, and standing long jump-tests and testosterone levels) between the groups, groups were analyzed separately. The serum levels of 25(OH)D, testosterone (TES), sex hormone binding globulin (SHBG), and insulin-like growth factor-1 (IGF-1) were analyzed by electrochemiluminescence immunoassay. Physical performance tests consisted of muscular fitness (sit-ups, push-ups, standing long jump) and aerobic fitness (12-minute-running) tests. The association of serum 25(OH)D with physical performance tests and anabolic hormones was analyzed using linear regression. Results: After controlling for the group, body mass index, and leisure-time physical activity, serum 25(OH)D level was positively associated with aerobic and muscular fitness (β = 0.15-0.20, all p < 0.05). Also, the participants with sufficient serum 25(OH)D levels (≥75 nmol/L) had better aerobic and muscular fitness and higher TES in group B, and better upper extremity muscular fitness in group A (all p < 0.05). In group A, there were 166 participants with serum levels of 25(OH) D < 75 nmol/L and 18 ≥ 75 nmol/L. In group B, the amounts were 92 (<75 nmol/L) and 136 (≥75 nmol/L), respectively. Conclusion: Serum 25(OH)D was positively associated with both aerobic and muscular fitness and those with sufficient vitamin D levels, had higher levels of TES. Thus, maintaining a sufficient serum 25(OH)D level may be beneficial for physical performance and anabolic state in young men.

Vitamin D in Health and Disease

Vitamin D (VD) is a fat-soluble hormone that plays a fundamental role not only in calcium homeostasis and bone metabolism, but also has anti-inflammatory and antioxidant properties, acting on both innate and adaptive immunity [...].

The Pathogenesis of Cardiac Arrhythmias in Vitamin D Deficiency

The global prevalence of vitamin D deficiency is more than 20%, and the main causes include insufficient intake, reduced absorption, abnormal metabolism, or resistance to its effects. The levels of serum vitamin D appear to influence cardiovascular risk, and the mechanism involved is linked to the transient outward current and the ultrarapid delayed rectifier K+ current densities, activated through the nuclear vitamin D receptor and Akt pathway. A significant number of studies have correlated vitamin D deficiency with an increased risk of developing cardiac arrhythmias and sudden cardiac death. For this reason, the purpose of this review is to analyze the relation between vitamin D deficiency and the pathogenesis of cardiac arrhythmias. Atrial fibrillation, increased QT interval, and QT dispersion were the most common findings associated with vitamin D deficiency. Due to the heterogeneity among existing studies, further research is necessary to confirm the existing data and to analyze its relationship with other types of arrhythmias.

Vitamin D as therapeutic modulator in cerebrovascular diseases: a mechanistic perspectives

Vitamin D deficiency has been linked to several major chronic diseases, such as cardiovascular and neurodegenerative diseases, diabetes, and cancer, linked to oxidative stress, inflammation, and aging. Vitamin D deficiency appears to be particularly harmful to the cardiovascular system, as it can cause endothelial dysfunctioning and vascular abnormalities through the modulation of various downstream mechanisms. As a result, new research indicates that therapeutic approaches targeting vitamin D inadequacies or its significant downstream effects, such as impaired autophagy, abnormal pro-inflammatory and pro-oxidant reactions, may delay the onset and severity of major cerebrovascular disorders such as stroke and neurologic malformations. Vitamin D modulates the various molecular pathways, i.e., Nitric Oxide, PI3K-Akt Pathway, cAMP pathway, NF-kB Pathway, Sirtuin 1, Nrf2, FOXO, in cerebrovascular disorder. The current review shows evidence for vitamin D's mitigating or slowing the progression of these cerebrovascular disorders, which are significant causes of disability and death worldwide.

Inadequate vitamin D intake among pregnant women in Malaysia based on revised recommended nutrient intakes value and potential dietary strategies to tackle the inadequacy

BACKGROUND/OBJECTIVES

Recently, the recommended nutrient intakes (RNI) for vitamin D for Malaysian aged 1-70 yrs has been revised from 5 µg/day to 15 µg/day. This study is aimed to assess the adequacy of vitamin D intake based on revised RNI and to recommend several dietary strategies to increase total vitamin D intake.

SUBJECTS/METHODS

Vitamin D intake from both food and supplement of 217 pregnant women was assessed using a validated food frequency questionnaire. Hypothetical effect of expanded supplementation and food fortifications strategies were modelled using the consumption data.

RESULTS

The results revealed that more than half (67.7%) of pregnant women had inadequate vitamin D intake (RNI < 15 µg/day). The modelling results demonstrated the potential of universal provision of 10 µg/day of multivitamins supplements in increasing vitamin D intake. Moreover, mandatory fortification of both milk and malted drink at single level of 5 µg/serving would lead to increase in vitamin D intake of Malaysians, particularly pregnant women.

CONCLUSIONS

The outcome of this study can be used as a reference for public health professionals to re-evaluate the existing Malaysian food fortification policies and supplementation recommendation for vitamin D for pregnant women.

Negative Air Ions in Neuropsychiatric Disorders

BACKGROUND

Air ions (AIs) are clusters of ionized particles present in the atmosphere, carrying an electrical charge of negative or positive polarity. Past speculations suggested that exposure to positive air ions may be harmful, while exposure to negative air ions (NAIs) may be associated with beneficial health effects. Increasing attention has been directed towards investigating the potential effect of NAIs on human brain activities since initial observations of their beneficial effects on some cognitive processes and mood.

AIMS

Given the paucity and scattered literature, our paper aims to review the available studies on potential positive effects of NAIs exposure on cognitive performances and depression.

DISCUSSION

The review of the literature seems to confirm the effects of NAIs on several brain functions. Indeed, a significant association between NAIs exposure and both well-being and high cognitive performances has been described. Furthermore, exposure to high concentrations of NAIs could be related to the improvement of depressive symptoms.

CONCLUSION

A growing evidence of data, although not yet conclusive, would suggest that NAIs might improve cognitive processes. These findings require specific and urgent controlled trials adopting systems based on AIs release to possibly prevent and treat cognitive dysfunctions present in a broad range of neuropsychiatric conditions.

Vitamin D and Stress Fractures in Sport: Preventive and Therapeutic Measures-A Narrative Review

There are numerous risk factors for stress fractures that have been identified in literature. Among different risk factors, a prolonged lack of vitamin D (25(OH)D) can lead to stress fractures in athletes since 25(OH)D insufficiency is associated with an increased incidence of a fracture. A 25(OH)D value of <75.8 nmol/L is a risk factor for a stress fracture. 25(OH)D deficiency is, however, only one of several potential risk factors. Well-documented risk factors for a stress fracture include female sex, white ethnicity, older age, taller stature, lower aerobic fitness, prior physical inactivity, greater amounts of current physical training, thinner bones, 25(OH)D deficiency, iron deficiency, menstrual disturbances, and inadequate intake of 25(OH)D and/or calcium. Stress fractures are not uncommon in athletes and affect around 20% of all competitors. Most athletes with a stress fracture are under 25 years of age. Stress fractures can affect every sporty person, from weekend athletes to top athletes. Stress fractures are common in certain sports disciplines such as basketball, baseball, athletics, rowing, soccer, aerobics, and classical ballet. The lower extremity is increasingly affected for stress fractures with the locations of the tibia, metatarsalia and pelvis. Regarding prevention and therapy, 25(OH)D seems to play an important role. Athletes should have an evaluation of 25(OH)D -dependent calcium homeostasis based on laboratory tests of 25-OH-D₃, calcium, creatinine, and parathyroid hormone. In case of a deficiency of 25(OH)D, normal blood levels of ≥30 ng/mL may be restored by optimizing the athlete’s lifestyle and, if appropriate, an oral substitution of 25(OH)D. Very recent studies suggested that the prevalence of stress fractures decreased when athletes are supplemented daily with 800 IU 25(OH)D and 2000 mg calcium. Recommendations of daily 25(OH)D intake may go up to 2000 IU of 25(OH)D per day.

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. .

Seasonal variability of the vitamin D effect on physical fitness in adolescents

Studies investigating the relationship between vitamin D and physical fitness in youth have provided inconsistent findings. Recent evidence indicates that the expression of receptors and vitamin D-modulated genes in young subjects has a seasonal profile. Therefore, we investigated the role of vitamin D on physical fitness across seasons in a total of 977 male adolescents. Anthropometrics, lifestyle, dietary habits, biochemical profiles and physical fitness were studied. Multiple linear regression models, including pairwise interaction terms involving total 25-OH-vitamin D, were fitted. The interacting effect of season and total 25-OH-vitamin D had a significant influence on physical fitness performance (spring and total 25-OH-vitamin D: ß 0.19, SE 0.07, p = 0.007; summer and total 25-OH-vitamin D: ß 0.10, SE 0.06, p = 0.11; autumn and total 25-OH-vitamin D: ß 0.18, SE 0.07, p = 0.01), whereas the main effect of total 25-OH-vitamin D alone was not significant (p = 0.30). Body fat percentage, recreational physical activity level, time spent per day gaming/TV-watching, smoking, and hemoglobin levels were also related to the physical fitness performance score. Future studies should further explore the role of seasonal-dependent effects of vitamin D on health.

Effect of vitamin D supplementation versus placebo on essential hypertension in patients with vitamin D deficiency: a double-blind randomized clinical trial

Findings from randomized trials addressing the effect of vitamin D supplementation and blood pressure are inconsistent and have been the subject of recent debate. This study aimed to assess the effect of vitamin D supplementation on primary hypertension. This double-blind randomized clinical trial was conducted on patients aged 26-84 years with essential hypertension from March 2017 to April 2019. Patients with vitamin D insufficiency (serum vitamin D levels 20-30 ng/ml) or vitamin D deficiency (serum vitamin D levels <20 ng/ml) were enrolled in the study. Patients were randomly assigned to receive vitamin D supplementation or placebo. Systolic and diastolic blood pressure was measured before the intervention and one and two months thereafter. Of 208 patients enrolled, 171 patients remained for analysis. The effect of vitamin D supplementation on systolic blood pressure was statistically significant in the first and second months after the intervention (P=0.004 and P=0.024, respectively). The effect of vitamin D supplementation on diastolic blood pressure was statistically significant in the first month after the intervention (P=0.046), but not in the second month (P=0.885). No evidence of drug side effects was reported in the two groups. The results of this trial are suggestive of the potential benefits of vitamin D supplementation on blood pressure end points. Therefore, the use of vitamin D may be recommended as an adjuvant drug in the treatment of essential hypertension in patients with vitamin D deficiency because it is safe and well-tolerated by the patients and can significantly reduce the systolic and diastolic blood pressure. Trial registration: Iranian Registry of Clinical Trials registration number: IRCT201703129014N151.

CYP3A4 and CYP11A1 variants are risk factors for ischemic stroke: a case control study

Background

This study aimed to investigate the roles of CYP3A4 and CYP11A1 variants in ischemic stroke (IS) susceptibility among the Han Chinese population.

Methods

Four hundred seventy-seven patients with IS and 493 healthy controls were enrolled. Seven single-nucleotide polymorphisms (SNPs) of CYP3A4 and CYP11A1 were genotyped by Agena MassARRAY. Odds ratio (OR) and 95% confidence intervals (CI) were calculated by logistic regression adjusted for age and gender.

Results

We found that CYP3A4 rs3735451 (OR = 0.81, p = 0.039) and rs4646440 (OR = 0.72, p = 0.021) polymorphisms decreased the risk of IS. CYP3A4 rs4646440 (OR = 0.74, p = 0.038) and CYP11A1 rs12912592 (OR = 1.58, p = 0.034) polymorphisms were correlated with IS risk in males. CYP3A4 rs3735451 (OR = 0.63, p = 0.031) and rs4646440 (OR = 0.57, p = 0.012) possibly weaken the IS susceptibility at age > 61 years. Besides, CYP3A4 rs4646437 (OR = 0.59, p = 0.029), CYP11A1 rs12912592 (OR = 1.84, p = 0.017) and rs28681535 (OR = 0.66, p = 0.038) were associated with IS risk at age ≤ 61 years. CYP11A1 rs28681535 TT genotype was higher high-density lipoprotein cholesterol level than the GT and GG genotype (p = 0.027).

Conclusions

Our findings indicated that rs3735451, rs4646440, rs4646437 in CYP3A4 and rs28681535 in CYP11A1 might be protective factors for IS, while CYP11A1 rs12912592 polymorphism be a risk factor for IS in Chinese Han population.

Association of Serum 25-Hydroxyvitamin D Level With Metabolic Phenotypes of Obesity in Children and Adolescents: The CASPIAN-V Study

Background and Objective: Different metabolic phenotypes of obesity are related to cardiometabolic risk factors in children and adolescents. Vitamin D, as one important factor, could be related to different subgroups of metabolic obesity and might affect metabolic disorders. The purpose of this study was to evaluate the relationship between serum 25-hydroxyvitamin D concentration and subsets of metabolic phenotypes of obesity in children and adolescents. Methods: This nationwide cross-sectional study was conducted in the framework of the fifth survey of a national surveillance program, the CASPIAN study. Overall, 2,594 students aged 7-18 years were assessed for 25-hydroxyvitamin D status. Metabolic syndrome (MetS) was defined according to the ATP III criteria modified for the pediatric age group. Participants were classified into four metabolic phenotypes of obesity according to categories of the BMI and metabolic status: "metabolically healthy obese" (MHO), "metabolically non-healthy non-obese" (MNHNO), "metabolically non-healthy obese" (MNHO), and "metabolically healthy non-obese" (MHNO). Multinomial logistic regression analysis was performed for evaluating the association of 25-hydroxyvitamin D status with different metabolic phenotypes of obesity. Results: In this study, 85.2% of participants were classified as MHNO, 11.0 % as MHO, 2.5% as MNHNO, and 1.3% as MNHO. The frequency of hypovitaminosis D was more prevalent in MNHO (85.3%) than in other phenotypes (MHNO: 70%; MHO: 76.5%; MNHNO: 78.1%, respectively; p < 0.05). In the multivariate model, hypovitaminosis D significantly increased the odds of being MHO (OR: 1.46; 95% CI: 1.07-1.77) and MNHO (OR: 2.89; 1.05-8.31) compared to the healthy group. Likewise, in multivariate model, per each unit (ng/mL) increment in 25-hydroxyvitamin D concentration, the odds of MNHNO and MNHO decreased significantly by 7% (OR: 0.93; 0.91-0.96) and 6% (OR: 0.94; 0.91-0.98) respectively. Conclusion: Our results support the hypothesis that 25-hydroxyvitamin D concentration is associated with metabolic obesity phenotypes. Longitudinal studies are necessary to assess the clinical impacts of this finding.

Vitamin D, Skeletal Muscle Function and Athletic Performance in Athletes-A Narrative Review

The active form of vitamin D (calcitriol) exerts its biological effects by binding to nuclear vitamin D receptors (VDRs), which are found in most human extraskeletal cells, including skeletal muscles. Vitamin D deficiency may cause deficits in strength, and lead to fatty degeneration of type II muscle fibers, which has been found to negatively correlate with physical performance. Vitamin D supplementation has been shown to improve vitamin D status and can positively affect skeletal muscles. The purpose of this study is to summarize the current evidence of the relationship between vitamin D, skeletal muscle function and physical performance in athletes. Additionally, we will discuss the effect of vitamin D supplementation on athletic performance in players. Further studies are necessary to fully characterize the underlying mechanisms of calcitriol action in the human skeletal muscle tissue, and to understand how these actions impact the athletic performance in athletes.

The vitamin D-folate hypothesis in human vascular health

The vitamin D-folate hypothesis has been proposed as an explanation for the evolution of human skin pigmentation. According to this hypothesis, a darkened skin pigment was adapted by early human populations living in equatorial Africa to protect against photodegradation of bioavailable folate by ultraviolet radiation (UVR). As humans moved away from the equator to more northern latitudes and occupied regions of lower UVR exposure and greater seasonal variation, however, depigmentation occurred to allow for adequate biosynthesis of vitamin D. Vitamin D and folate are both recognized for their evolutionary importance in healthy pregnancy and early childhood development. More recently, evidence has emerged demonstrating the importance of both vitamin D and folate in vascular health via their effects in reducing oxidative stress and improving nitric oxide (NO) bioavailability. Thus, populations with darkened skin pigmentation may be at elevated risk of vascular dysfunction and cardiovascular disease in low UVR environments due to hypovitaminosis D; particularly important as darkly-pigmented African-Americans represent an at-risk population for cardiovascular disease. Conversely, lightly pigmented populations in high UVR environments may be at risk of deleterious vascular effects of UVR-induced folate degradation. The focus of this review is to explore the currently available literature regarding the potential role of UVR in vascular health via its differential effects on vitamin D and folate metabolism, as well as the interaction between skin pigmentation, genetics, and environment in modulating the vascular influence of UVR exposure.

Vitamin D supplementation alters the expression of genes associated with hypertension and did not induce DNA damage in rats

Vitamin D3 deficiency has been correlated with altered expression of genes associated with increased blood pressure (BP); however, the role of vitamin D3 supplementation in the genetic mechanisms underlying hypertension remains unclear. Thus, the aim of this study was investigate the consequences of vitamin D3 supplemented (10,000 IU/kg) or deficient (0 IU/kg) diets on regulation of expression of genes related to hypertension pathways in heart cells of spontaneously hypertensive rats (SHR) and normotensive Wistar Kyoto (WKY) controls. An additional aim was to assess the impact of vitamin D3 on DNA damage and oxidative stress markers. The gene expression profiles were determined by PCR array, DNA damage was assessed by an alkaline comet assay, and oxidative stress markers by measurement of thiobarbituric acid reactive substances (TBARS) and glutathione (GSH) levels. In SHR rats data showed that the groups of genes most differentially affected by supplemented and deficient diets were involved in BP regulation and renin-angiotensin system. In normotensive WKY controls, the profile of gene expression was similar between the two diets. SHR rats were more sensitive to changes in gene expression induced by dietary vitamin D3 than normotensive WKY animals. In addition to gene expression profile, vitamin D3 supplemented diet did not markedly affect DNA or levels of TBARS and GSH levels in both experimental groups. Vitamin D3 deficient diet produced lipid peroxidation in SHR rats. The results of this study contribute to a better understanding of the role of vitamin D3 in the genetic mechanisms underlying hypertension. Abbreviations: AIN, American Institute of Nutrition; EDTA, disodium ethylenediaminetetraacetic acid; GSH, glutathione; PBS, phosphate buffer solution; SHR, spontaneously hypertensive rats; TBARS, thiobarbituric acid reactive substances; WKY, Wistar Kyoto.

The effects of vitamin D supplementation on endothelial activation among patients with metabolic syndrome and related disorders: a systematic review and meta-analysis of randomized controlled trials

Background and objective

The current systematic review and meta-analysis of randomized controlled trials (RCTs) was conducted to summarize the effect of vitamin D supplementation on endothelial activation among patients with metabolic syndrome and related disorders.

Methods

Cochrane library, Embase, PubMed, and Web of Science database were searched to identify related RCTs published before 30th April 2018. The heterogeneity among the included studies was assessed using Cochran’s Q test and I-square (I²) statistic. Data were pooled by using the random-effect model and standardized mean difference (SMD) was considered as summary effect size.

Results

Fourteen clinical trials that contained a total of 1253 participants were included in the current meta-analysis. Vitamin D supplementation significantly decreased von willebrand factor (vWF) (SMD -0.27; 95% CI, − 0.46, − 0.08; P = 0.006; I²:40.5%). However, we found no significant impact of vitamin D supplementation on intercellular adhesion molecule 1(ICAM-1) (SMD -1.96; 95% CI, − 4.02, 0.09; P = 0.06; I²:97.4%), vascular celladhesion molecule 1 (VCAM-1) (SMD -0.50; 95% CI, − 1.19, 0.19; P = 0.15; I²:91.2%), on E-selectin (SMD -0.04; 95% CI, − 0.36, 0.28; P = 0.81; I²:78.8%) and endothelin (SMD -0.49; 95% CI, − 1.18, 0.19; P = 0.15; I²:90.5%). The pooled data from trials of vitamin D supplementation with dosage of ≤4000 IU/day (− 0.37, 95% CI: -0.65, − 0.10, I²: 73.5%) significantly reduced vWF concentrations, while there was no effect of vitamin D supplementation on vWF concentrations among trials with the dosage of intervention > 4000 IU/day (− 0.17, 95% CI: -0.43, 0.10, I²: 0.0%). VWF concentrations significantly reduced in pooled data from trials with duration study ≤8 weeks (− 0.37, 95% CI: -0.67, − 0.07, I²: 60.6%), but there was no effect of vitamin D supplementation on vWF concentrations among trials with > 8 weeks (− 0.20, 95% CI: -0.45, 0.05, I²: 0.0%). While there was no effect of vitamin D supplementation on vWF concentrations among trials with total sample size of ≤60 patients (− 0.03, 95% CI: -0.42, 0.36, I²: 0.0%), vWF concentrations in trials with more than 60 patients decreased significantly (− 0.34, 95% CI: -0.56, − 0.12, I²: 60.9%).

Conclusions

Overall, the current meta-analysis demonstrated that vitamin D supplementation to patients with metabolic syndrome and related disorders resulted in an improvement in vWF, but did not affect ICAM-1, VCAM-1, E-selectin and endothelin levels.

Electronic supplementary material

The online version of this article (10.1186/s12986-018-0320-9) contains supplementary material, which is available to authorized users.

Assessing the effect of oral activated vitamin D on overall survival in hemodialysis patients: a landmark analysis

BACKGROUND

Patients with end stage renal disease have a high all-cause and cardiovascular mortality. Secondary hyperparathyroidism and vitamin D deficiency are considered part of the mechanism for the excess mortality observed. We aimed to evaluate the relationship between vitamin D use and all-cause mortality.

METHODS

In this retrospective cohort study, we included all incident patients who started hemodialysis in Taiwan between 2001 and 2009. Patients were followed from landmark time, i.e., the 360th day from hemodialysis initiation, through the end of 2010 or death. We evaluated the association between activated vitamin D use or not before landmark time and all-cause mortality using conditional landmark analysis with Cox regression. We used group-based trajectory model to categorize high-dose versus average-dose users to evaluate dose-response relationships.

RESULTS

During the median follow-up of 1019 days from landmark time, vitamin D users had a lower crude mortality rate than non-users (8.98 versus 12.93 per 100 person-years). Compared with non-users, vitamin D users was associated with a lower risk of death in multivariate Cox model (HR 0.91 [95% CI, 0.87-0.95]) and after propensity score matching (HR 0.94 [95% CI, 0.90-0.98]). High-dose vitamin D users had a lower risk of death than conventional-dose users, HR 0.75 [95% CI, 0.63-0.89]. The association of vitamin D treatment with reduced mortality did not alter when we re-defined landmark time as the 180th day or repeated analyses in patients who underwent hemodialysis in the hospital setting.

CONCLUSIONS

Our findings supported the survival benefits of activated vitamin D among incident hemodialysis patients.

Vitamin D status in diabetic children and adolescents

INTRODUCTION

Besides its role in calcium homeostasis, vitamin D (VD) has an important immuno-mudulation effect. However, its role in autoimmune diseases such as type 1 diabetes is under discussion. This study designed to investigate serum VD status in children and adolescents with and without diabetes.

MATERIALS AND METHODS

In a case-control study, 85 diabetic and 85 non-diabetic control (total 170) aged 1-15 yr. were enrolled. History of breast feeding and vitamin supplementation was obtained; growth indices and serum levels of Calcium, phosphorous, Alkaline-Phosphatase (ALP), Hemoglobin-A1c and VD were measured and analyzed.

RESULTS

The mean values for VD in case and control groups were 12.80 ± 10.59 and 15.85 ± 9.92 nmol/L, respectively (p = 0.057). Serum VD status in these two groups was sufficient in 5.88% and 9.41%, insufficient in 18% and 14%, and deficient in 75.29% and 76.74%, respectively. Compared to the controls, diabetics had more history of breast-feeding (62.35% vs. 42.35%; p = 0.017) and higher serum ALP levels (772.34 ± 309.89 vs. 657.99 ± 395.11 U/L; p = 0.032).

CONCLUSION

More frequency of breast-feeding, higher serum ALP and mildly lower serum level of VD in diabetics suggests a significant difference in VD status in diabetics compared to the healthy peers indicating a potential role of this deficiency in the disease process.

Effect of Vitamin D supplementation on body composition and cardiorespiratory fitness in overweight men-a randomized controlled trial

PURPOSE

Several observational studies have shown an association between vitamin D deficiency and non-skeletal major health issues including impaired cardiorespiratory fitness and adiposity. Only a few studies have examined the impact of vitamin D supplementation on these conditions and the results are ambiguous. The aim of this study was to examine the effect of vitamin D supplementation on body composition and cardiorespiratory fitness in overweight/obese men with vitamin D deficiency.

METHODS

This study was a prospective, placebo controlled, double blinded, randomized trial with a study period of 6 months. Forty overweight/obese men (BMI > 25 kg/m²) with vitamin D deficiency (25(OH)D ≤ 55 nmol/L) were randomized to receive either 2000 IU Cholecalciferol drops or the equivalent amount of drops of placebo. At baseline and follow up body composition and cardiorespiratory fitness were measured and blood samples were obtained. Body composition was measured using bioelectrical impedance analysis (BIA) and cardiorespiratory fitness using cardiopulmonary exercise test (CPET). The primary outcomes were changes in percentage body fat and in maximum oxygen uptake (VO_2max).

RESULTS

No statistically significant difference between the placebo and the intervention group regarding changes in percentage body fat (p = 0.54) and VO_2max (p = 0.90) was observed. Moreover, there was no statistically significant difference between the groups concerning changes in BMI (p = 0.26), maximum load (p = 0.89) and oxygen uptake at anaerobic threshold (AT) (p = 0.14).

CONCLUSIONS

We conclude that treatment with 2000 IU/d vitamin D for 6 months does not impact body composition or maximum oxygen uptake in overweight/obese men with vitamin D deficiency.

Rationale and design of a placebo controlled randomized trial to assess short term, high-dose oral cholecalciferol on select laboratory and genomic responses in African Americans with hypovitaminosis D

Cardiovascular Disease (CVD) and related disorders remain a leading cause of health disparities and premature death for African Americans. Hypovitaminosis D is disproportionately prevalent in African Americans and has been linked to CVD and CVD risk factors including hypertension, diabetes and obesity. Thus, hypovitaminosis D may represent a common pathway influencing CV risk factors in a select subgroup of persons. The purpose of this paper is to report the study design of a prospective eight week prospective double-blind randomized, placebo-controlled trial (n = 330 allocated 2:1 to intervention vs. control) to assess the effect of placebo vs. high-dose oral cholecalciferol (100,000 IU vitamin D3 at baseline and week 2) on 6-week change of select biologic cardiometabolic risk factors (including parathyroid hormone to assess biologic activity, pro-inflammatory/pro-thrombotic/fibrotic markers, insulin sensitivity and vitamin D metabolites) and their relationship to vitamin D administration and modification by vitamin D receptor polymorphisms in overweight, hypertensive African Americans with hypovitaminosis D. Findings from this trial will present insights into potential causal links between vitamin D repletion and mechanistic pathways of CV disease, including established and novel genomic markers.

Docosahexaenoic acid reversed atherosclerotic changes in human endothelial cells induced by palmitic acid in vitro

Abnormal activity of atherosclerotic endothelial cells paving luminal surface of blood vessels has been described in many diseases. It has been reported that natural polyunsaturated fatty acids such as docosahexaenoic acid exert therapeutic effects in atherosclerotic condition. Human umbilical vein endothelial cells were treated with 1mM palmitic acid for 48 hours and exposed to 40μM docosahexaenoic acid for the next 24 hours. Real-time polymerase chain reaction analysis was used to measure the expression of PTX3, iNOS, and eNOS. The level of nitric oxide was detected by Griess reagent. The transcription level of genes participating in coagulation and blood pressure was studied by polymerase chain reaction array. Docosahexaenoic acid improved the survival rate by reducing apoptosis rate (P < .05). Compared with that of the group given palmitic acid, attenuation of proinflammatory status was indicated by reduced interleukin-6 (P < .05) and prostaglandin E₂ levels. All genes PTX3, iNOS, and eNOS were down-regulated after being exposed to docosahexaenoic acid. Nitric oxide contents were not changed in cells exposed to docosahexaenoic acid. Polymerase chain reaction array confirmed the reduction of LPA, PDGFβ, ITGA2, SERPINE1, and FGA after exposure to docosahexaenoic acid for 24 hours (P < .05). Docosahexaenoic acid had potential to blunt atherosclerotic changes in the modulation of genes controlling blood coagulation, pressure, and platelet function.

SIGNIFICANCE OF THE STUDY

The current experiment showed that docosahexaenoic acid could reverse atherosclerotic changes in human endothelial cells induced by palmitic acid. The increased levels of interleukin-6 and prostaglandin E₂ in atherosclerotic cells were returned to near-to-normal status. Gene expression analysis showed a reduced activity of genes participating in atherosclerotic endothelial cells treated by docosahexaenoic acid. The expression of genes related to cell clotting activity was also similar to that of normal cells.

Frailty Is Associated with an Increased Risk of Major Adverse Cardiac Events in Patients with Stable Claudication

BACKGROUND

Frailty, a syndrome characterized by decreased physiologic reserves and resistance to stressors, is associated with disability, poor surgical outcomes, and mortality. We evaluated the impact of frailty on cardiovascular disease (CVD) events in peripheral arterial disease (PAD) patients with intermittent claudication.

METHODS

We conducted a retrospective review of patients with stable intermittent claudication enrolled in the OMEGA-PAD study between 2010 and 2015. The modified frailty index (mFI) is a retrospectively validated index of frailty derived from the Canadian Study of Health and Aging and was used in this study to categorize frailty as low, medium, or high. Our outcome was time to occurrence of a major adverse cardiac event (MACE), defined as a composite endpoint of myocardial infarction, coronary revascularization, stroke, or CVD-related death. Cox proportional hazards models were used to calculate relative hazards ratio.

RESULTS

There were 129 subjects with a mean age of 67 years, 97% were men, 36% were diabetic, and 33% had known coronary heart disease. When the mFI criteria were applied, 38 subjects were "low" frailty, 72 were "medium" frailty, and 19 were "high" frailty. During the median follow-up period of 34 months (interquartile range: 25-43), 29 subjects experienced a MACE. When compared to the lowest mFI, patients with medium frailty were 2.8 times more likely to have an event (95% confidence interval [CI]: 0.95-8.46, P = 0.06), whereas patients with a high mFI were 4.8 times as likely (95% CI: 1.43-15.8, P = 0.01). In a model adjusted for age, smoking status, and presence of diabetes, those with a medium mFI were 4.3 times more likely to have an event (95% CI: 1.37-13.7, P = 0.01) and those with a high mFI were 9.2 times as likely (95% CI: 2.6-32.4, P = 0.001).

CONCLUSIONS

Higher mFI category is associated with a significantly increased risk of MACE in PAD patients with stable claudication. Frailty may serve as a useful adjunct for assessment of overall cardiac risk, particularly as treatment options are being contemplated.

Associations of vitamin D with insulin resistance, obesity, type 2 diabetes, and metabolic syndrome

The aim of this study is to determine the relationships of vitamin D with diabetes, insulin resistance obesity, and metabolic syndrome. Intra cellular vitamin D receptors and the 1-α hydroxylase enzyme are distributed ubiquitously in all tissues suggesting a multitude of functions of vitamin D. It plays an indirect but an important role in carbohydrate and lipid metabolism as reflected by its association with type 2 diabetes (T2D), metabolic syndrome, insulin secretion, insulin resistance, polycystic ovarian syndrome, and obesity. Peer-reviewed papers, related to the topic were extracted using key words, from PubMed, Medline, and other research databases. Correlations of vitamin D with diabetes, insulin resistance and metabolic syndrome were examined for this evidence-based review. In addition to the well-studied musculoskeletal effects, vitamin D decreases the insulin resistance, severity of T2D, prediabetes, metabolic syndrome, inflammation, and autoimmunity. Vitamin D exerts autocrine and paracrine effects such as direct intra-cellular effects via its receptors and the local production of 1,25(OH)₂D₃, especially in muscle and pancreatic β-cells. It also regulates calcium homeostasis and calcium flux through cell membranes, and activation of a cascade of key enzymes and cofactors associated with metabolic pathways. Cross-sectional, observational, and ecological studies reported inverse correlations between vitamin D status with hyperglycemia and glycemic control in patients with T2D, decrease the rate of conversion of prediabetes to diabetes, and obesity. However, no firm conclusions can be drawn from current studies, because (A) studies were underpowered; (B) few were designed for glycemic outcomes, (C) the minimum (or median) serum 25(OH) D levels achieved are not measured or reported; (D) most did not report the use of diabetes medications; (E) some trials used too little (F) others used too large, unphysiological and infrequent doses of vitamin D; and (G) relative paucity of rigorous clinical data on the effects of vitamin D sufficiency on non-calcium endpoints. Although a large number of observational studies support improving T2D, insulin resistance, obesity, and metabolic syndrome with vitamin D adequacy, there is a lack of conclusive evidence from randomized control clinical trials that, these disorders are prevented following optimization of serum levels of 25(OH)D. However, none of the currently conducted clinical studies would resolve these issues. Thus, specifically designed, new clinical studies are needed to be conducted in well-defined populations, following normalizing the serum vitamin D levels in vitamin D deficient prediabetes subjects, to test the hypothesis that hypovitaminosis D worsens these disorders and correction would alleviate it.

Role of vitamin D deficiency in systemic lupus erythematosus incidence and aggravation

Vitamin D is one of the main groups of sterols; playing an important role in phospho-calcic metabolism. The conversion of 7-dehydrocholesterol to pre- vitamin D3 in the skin, through solar ultraviolet B radiation, is the main source of vitamin D. Since lupus patients are usually photosensitive, the risk of developing vitamin D deficiency in is high in this population. Although evidences showed the connotation between systemic lupus erythematosus (SLE) and vitamin D through which SLE can lead to lower vitamin D levels, it is also important to consider the possibility that vitamin D deficiency may have a causative role in SLE etiology. This paper analyzes existing data from various studies to highlight the role of vitamin D deficiency in SLE occurrence and aggravation and the probable efficacy of vitamin D supplementation on SLE patients. We searched “Science Direct” and “Pub Med” using “Vitamin D” and “SLE” for finding the studies focusing on the association between vitamin D deficiency and SLE incidence and consequences. Evidences show that vitamin D plays an important role in the pathogenesis and progression of SLE and vitamin D supplementation seems to ameliorate inflammatory and hemostatic markers; so, can improve clinical subsequent.

Identification of Novel Non-secosteroidal Vitamin D Receptor Agonists with Potent Cardioprotective Effects and devoid of Hypercalcemia

Vitamin D regulates many biological processes, but its clinical utility is limited by its hypercalcemic effect. Using a virtual screening platform to search novel chemical probes that activate the vitamin D signaling, we report discovery of novel non-steroidal small-molecule compounds that activate the vitamin D receptor (VDR), but are devoid of hypercalcemia. A lead compound (known as VDR 4-1) demonstrated potent transcriptional activities in a VDR reporter gene assay, and significantly ameliorated cardiac hypertrophy in cell culture studies and in animal models. VDR 4-1 also effectively suppressed secondary hyperparathyroidism in 1α-hydroxylase knockout mice. In contrast to 1α,25-dihydroxyvitamin D₃ (1,25-D₃ or calcitriol), a naturally occurring VDR agonist, VDR 4-1 therapy even at high doses did not induce hypercalcemia. These findings were accompanied by a lack of upregulation of calcium transport genes in kidney and in the gut providing a mechanism for the lack of hypercalcemia. Furthermore, VDR 4-1 therapy significantly suppressed cardiac hypertrophy and progression to heart failure in both vitamin D deficient and normal mice without inducing significant hypercalcemia. In conclusion, we have identified a unique VDR agonist compound with beneficial effects in mouse models of hyperparathyroidism and heart failure without inducing significant hypercalcemia.

Role of serum MMP-9 levels and vitamin D receptor polymorphisms in the susceptibility to coronary artery disease: An association study in Iranian population

BACKGROUND

Data concerning the association of serum levels of vitamin D and metalloproteinases and vitamin D receptor gene polymorphism with coronary artery disease (CAD) is not fully demonstrated. The present study aimed to evaluate the association of vitamin D receptor gene polymorphism, serum levels of 25(OH) vitamin D and metalloproteinase-9 (MMP-9) with CAD.

METHODS

104 patients with CAD and 69 Non-CAD subjects were included in current study. Vitamin D receptor genotypes were determined by PCR-RFLP method. The 25(OH) vitamin D and MMP-9 were determined by ELISA assay.

RESULTS

There was a significant reduction of vitamin D in CAD patients (P=0.001). The metalloproteinase 9 levels of CAD patient was increased significantly compared with controls (P=0.001). A significant reverse correlation also was found between MMP-9 concentration and 25(OH) vitamin D levels of patients (r=-0.28, P<0.001). In addition, we identified that VDR gene FokI polymorphism was significantly associated with CAD. Furthermore, MMP-9 levels of CAD patients with ff genotype of FokI polymorphism was higher significantly than patients with FF and Ff genotypes. It has been also found that MMP-9 levels of CAD patients with ff genotype of FokI polymorphism was higher significantly than patients with FF and Ff genotypes.

CONCLUSION

Our results indicated that 25(OH) vitamin D, MMP-9 levels and VDR gene FokI polymorphisms play a critical role in the development and progression of CAD and may contribute to susceptibility to CAD in Iranian populations.

The impact of vitamin D supplement intake on vascular endothelial function; a systematic review and meta-analysis of randomized controlled trials

Aim: to systematically review and conduct a meta-analysis of randomized controlled trials investigating the impact of vitamin D supplementation on endothelial function. Method: We searched PubMed-Medline, SCOPUS, Web of Science and Google Scholar (until June 2016) to detect prospective studies evaluating the impact of vitamin D supplementation on endothelial function indexes. We used random effects models (using DerSimonian-Laird method) and generic inverse variance methods to synthesize quantitative data. We used the leave-one-out method for sensitivity analysis. To quantitatively assess the heterogeneity we used the I² index. Systematic review registration: CRD42016039329. Results: From a total of 213 entries identified, 12 studies were appropriate for inclusion into the final analysis. The meta-analysis indicated a significant enhancement in flow-mediated dilation (FMD) following D supplementation (vitamin D intervention group versus control group 1.27 %, (95% CI 0.20 to 2.34, N = 11 arms, heterogeneity p = 0.054; I² 51.2 %). These findings were robust in sensitivity analyses. Conclusions: This meta-analysis suggested that vitamin D supplementation may improve endothelial function. Randomized control trials with a longer-term follow-up are warranted to clarify the existing controversies and shed light on the potential underlying mechanisms.

A study of cognitive functions in female elderly patients with osteoporosis: a multi-center cross-sectional study

OBJECTIVES

To investigate changes of cognitive performances in female elderly patients with osteoporosis and to determine whether any impairments can be attributed to dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis.

METHODS

This cross-sectional study included 277 postmenopausal women, who were divided into an osteoporosis patients group (n = 170) and an age, gender and educational history matching control group (n = 107). All the subjects completed a set of neuropsychological tests for the elderly for cognitive assessment, which included measures of executive function, episodic memory, attention and processing speed, semantic memory, and visuospatial construction. Blood biomarkers for osteoporosis, as well as diurnal rhythms of cortisol levels were used as cognitive performance correlation parameters in linear multivariate regression analyses.

RESULTS

Individuals with osteoporosis had poorer cognitive scores (P < 0.001). When dividing the osteoporosis patients according to their Mini-Mental State Examination scores into mild cognitive impairment (MCI) and normal cognitive (NC) performance groups, Auditory Verbal Learning trial 1-5 scores were lower (P = 0.006) and Trail Making Test-A scores were higher (P = 0.05) in the MCI compared to the NC group. Further comparison of the MCI and NC groups revealed that declarative memory was inversely associated with cortisol levels (P < 0.001), but this association became marginal when 25-hydroxy vitamin D was included in the linear multivariate regression analyses (P = 0.06).

CONCLUSIONS

Patients with osteoporosis are prone to cognitive impairments especially declarative memory deficits. The cognitive impairment may be the result of HPA axis dysregulation but 25-hydroxy vitamin D serum concentrations might be compensatory or even a potent contributing factor.

Association of Vitamin D Deficiency with Coronary Artery Disease

INTRODUCTION

Coronary Artery Disease (CAD) is a major global health problem. Recent studies demonstrated that lower vitamin D level (<30ng/ml) is associated with higher blood pressure and directly or indirectly with CAD, due to vascular endothelial damage. However the results are inconsistent.

AIM

To find the association of vitamin D deficiency with CAD.

MATERIALS AND METHODS

In this cross-sectional observational study, serum vitamin D level was measured in 315 patients who underwent coronary angiography.

RESULT

The mean (±SD) vitamin D was 13.40ng/ml (±10.40). However, the patients with normal coronary artery had much lower mean vitamin D (11.30ng/ml±9.50) as compared to the patients with CAD (14.10ng/ml±10.70). The mean (±SD) vitamin D levels were 19.00ng/ml (±16.50), 14.10ng/ml (±11.10) and 13.20ng/ml (±8.80) in patients with CAD with 50%-70%, >70%-90% and >90% stenosis respectively (p= 0.46) and 15.20ng/ml (±13.00), 15.50ng/ml (±11.30) and 11.80ng/ml (±7.00) in patients with CAD with single, double and triple vessels disease respectively (p= 0.14). The frequency of vitamin D deficiency were 66.70%, 83.20 % and 83.10% in patients with CAD with 50% -70%, >70%-90% and >90% stenosis respectively and 81.40%, 80.00% and 83.50% in patients with single, double and triple vessel disease respectively, as compared to 89.30% in patients with normal coronary artery (p= 0.41 and 0.075). So, all the study groups of CAD had low serum vitamin D level and high frequency of vitamin D deficiency, which was statistically insignificant.

CONCLUSION

Prevalence of vitamin D deficiency is very high in CAD, but it does not correlate with the angiographic severity of CAD.

Vitamin D status and V[combining dot above]O2peak during a skate treadmill graded exercise test in competitive ice hockey players

Vitamin D status has been associated with cardiorespiratory fitness (CRF) in cross-sectional investigations in the general population. Data characterizing the association between 25-hydroxyvitamin D (25(OH)D) concentration and CRF in athletes are lacking. Junior and collegiate ice hockey players were recruited from the Minneapolis, MN (44.9° N), area during the off-season period (May 16-June 28). The purpose of this study was to examine the cross-sectional association between 25(OH)D concentration and CRF in a sample population of competitive ice hockey players. Circulating 25(OH)D level was assessed from a capillary blood sample analyzed using liquid chromatography-tandem mass spectrometry. V[Combining Dot Above]O2peak during a skate treadmill graded exercise test (GXT) was used to assess CRF. Data on both 25(OH)D concentration and V[Combining Dot Above]O2peak were available for 52 athletes. Insufficient 25(OH)D concentrations were found in 37.7% of the athletes (<32 ng·ml). Vitamin D status was not significantly associated with any physiological or physical parameter during the skate treadmill GXT.

Increased Incidence of Hypovitaminosis D Among Patients Requiring Treatment for Cerebral Aneurysms

OBJECTIVE

Aneurysmal subarachnoid hemorrhage management is hampered by our incomplete understanding of what variables promote aneurysm formation, growth, and rupture. Because hypovitaminosis D has been identified as a risk factor for other vascular diseases, we examined its association with cerebral aneurysms requiring treatment.

METHODS

We retrospectively reviewed charts of patients with cerebral aneurysms with recorded 25-hydroxy vitamin D levels undergoing treatment at our institution from May 2010 to May 2015. We compared these patients with a group of patients without aneurysms. We used multivariable Poisson regression and backward elimination to identify factors associated with cerebral aneurysms, with a threshold P < 0.20. A propensity-matching algorithm was used, incorporating all factors with P < 0.10 in our regression model.

RESULTS

Patients in the aneurysm group were older than those in the control group (P = 0.001) and more likely to be female (P = 0.004), to be tobacco users (P < 0.001), and to have a diagnosis of hypertension (P = 0.001), but ethnicity, body mass index, and diabetes rates did not differ. Vitamin D levels in the aneurysm group were lower than in the control group (23.3 ± 12.3 vs. 28.7 ± 14.1 ng/mL, P = 0.001), and the patients were more likely to be vitamin D deficient (P = 0.028). Multivariable Poisson regression demonstrated that vitamin D level, tobacco use, age, and sex were significantly associated with aneurysms requiring treatment (P < 0.05). The propensity-matching algorithm confirmed a significant difference in vitamin D levels between the aneurysm and control groups (P = 0.01).

CONCLUSIONS

Patients with cerebral aneurysms requiring treatment have a significantly higher incidence of hypovitaminosis D compared with patients in a control group.

Vitamin D and Cardiac Differentiation

Calcitriol (1,25-dihydroxycholecalciferol or 1,25-D3) is the hormonally active metabolite of vitamin D. Experimental studies of vitamin D receptors and 1,25-D3 establish calcitriol to be a critical regulator of the structure and function of the heart. Clinical studies link vitamin D deficiency with cardiovascular disease (CVD). Emerging evidence demonstrates that calcitriol is highly involved in CVD-related signaling pathways, particularly the Wnt signaling pathway. Addition of 1,25-D3 to cardiomyocyte cells and examination of its effects on cardiomyocytes and mainly Wnt11 signaling allowed the specific characterization of the role of calcitriol in cardiac differentiation. 1,25-D3 is demonstrated to: (i) inhibit cell proliferation without promoting apoptosis; (ii) decrease expression of genes related to the regulation of the cell cycle; (iii) promote formation of cardiomyotubes; (iv) induce expression of casein kinase-1-α1, a negative regulator of the canonical Wnt signaling pathway; and (v) increase expression of noncanonical Wnt11, which has been recognized to induce cardiac differentiation during embryonic development and in adult cells. Thus, it appears that vitamin D promotes cardiac differentiation through negative modulation of the canonical Wnt signaling pathway and upregulation of noncanonical Wnt11 expression. Future work to elucidate the role(s) of vitamin D in cardiovascular disorders will hopefully lead to improvement and potentially prevention of CVD, including abnormal cardiac differentiation in settings such as postinfarction cardiac remodeling.

Contribution of vitamin D deficiency to the risk of coronary heart disease in subjects with essential hypertension

BACKGROUND

Vitamin D deficiency is proposed as a risk factor for coronary heart disease (CHD). An inverse relation was observed between serum 25-Hydroxy-Vitamin-D level and incidence of hypertension. This study aimed to evaluate the predictive value of serum 25-Hydroxy-Vitamin-D in improvement of CHD risk-stratification in patients with hypertension.

METHODS

In this cohort, we followed 1586 patients with essential hypertension (1078 diabetic and 508 non-diabetic) for 8.5 years. Physician-adjudicated first hard CHD event was the primary outcome. Cox regression analysis was used to investigate the association between 25-Hydroxy-Vitamin-D quartiles and incident CHD. 25-Hydroxy-Vitamin-D was also added to the Framingham Risk Score (FRS) and Net-Reclassification-Improvement (NRI) and Integrated-Discriminant-Improvement (IDI) were used to examine improved reclassification.

RESULTS

During follow-up, 176 events were recorded. Patients in the lowest quartile of 25-Hydroxy-Vitamin-D experienced the most number of hard CHD events. A significant linear trend was observed in hazard ratios (HR) of incident hard CHD events in 25-Hydroxy-Vitamin-D quartiles which remained significant after multiple adjustments for conventional CHD risk-factors (HRs in full-adjusted model: 2.87 [1.76-4.70] for 1st quartile, 2.31 [1.39-3.83] for 2nd quartile and 1.87 [1.15-3.03] for 3rd quartile, compared with the highest quartile; p-for-trend<0.001). Addition of 25-Hydroxy-Vitamin-D to FRS could improve CHD risk-estimation (relative-IDI = 15%, p-value<0.001). Addition of 25-Hydroxy-Vitamin-D to FRS successfully reclassified 33% [18-49] of patients with hypertension among CHD risk groups (p-value<0.001).

CONCLUSION

We observed that serum 25-Hydroxy-Vitamin-D is independently associated with future hard CHD events and improves its prediction in patients with essential hypertension. Addition of serum 25-Hydroxy-Vitamin-D to CHD risk-estimation models may have additive values.

Plausible ergogenic effects of vitamin D on athletic performance and recovery

The purpose of this review is to examine vitamin D in the context of sport nutrition and its potential role in optimizing athletic performance. Vitamin D receptors (VDR) and vitamin D response elements (VDREs) are located in almost every tissue within the human body including skeletal muscle. The hormonally-active form of vitamin D, 1,25-dihydroxyvitamin D, has been shown to play critical roles in the human body and regulates over 900 gene variants. Based on the literature presented, it is plausible that vitamin D levels above the normal reference range (up to 100 nmol/L) might increase skeletal muscle function, decrease recovery time from training, increase both force and power production, and increase testosterone production, each of which could potentiate athletic performance. Therefore, maintaining higher levels of vitamin D could prove beneficial for athletic performance. Despite this situation, large portions of athletic populations are vitamin D deficient. Currently, the research is inconclusive with regards to the optimal intake of vitamin D, the specific forms of vitamin D one should ingest, and the distinct nutrient-nutrient interactions of vitamin D with vitamin K that affect arterial calcification and hypervitaminosis. Furthermore, it is possible that dosages exceeding the recommendations for vitamin D (i.e. dosages up to 4000-5000 IU/day), in combination with 50 to 1000 mcg/day of vitamin K₁ and K₂ could aid athletic performance. This review will investigate these topics, and specifically their relevance to athletic performance.

Evaluating Vitamin D Repletion Regimens and Effects in Veteran Patients

BACKGROUND

There are wide variations in recommended dosing for vitamin D repletion. The identification of specific dosing thresholds to optimize repletion of 25-hydroxyvitamin D3 (also known as 25(OH)D) may help narrow the wide spectrum of vitamin D dosing.

OBJECTIVE

The primary objective of this study was to evaluate vitamin D treatment regimens and their dose response effect on vitamin D serum levels. Secondary outcomes include evaluation of the frequency of monitoring vitamin D serum levels and prescription adherence.

METHODS

This was a multicenter, retrospective data extraction analysis conducted in patients who initiated monotherapy of ergocalciferol and cholecalciferol between January 1, 2005 and December 31, 2010. Following vitamin D therapy initiation, changes in laboratory values, frequency of laboratory monitoring, and prescription adherence were assessed. Ergocalciferol and cholecalciferol groups were separately organized into quartiles to identify dosing ranges that had the most impact on changes in 25(OH)D laboratory values.

RESULTS

There were 2272 and 4140 monotherapy patients in the ergocalciferol and cholecalciferol groups, respectively. Cholecalciferol mean doses between 600 and 1100 IU had similar changes in 25(OH)D ranging from 8 to 9.1 ng/mL. Cholecalciferol mean doses of 2700 IU had 12.7 ng/mL 25(OH)D increase (P < 0.05). Ergocalciferol at mean doses of 11 000 IU had a 19.9 ng/mL increase of 25(OH)D (P < 0.05). At baseline 25(OH)D levels less than 15 ng/mL, 90% of subjects reached a therapeutic 25(OH)D level with a cumulative 300 000 IU cholecalciferol dose. Adherence, calculated by medication possession ratio, was greater with cholecalciferol than ergocalciferol (87% compared with 68%).

CONCLUSIONS

Lower vitamin D dose ranges had a comparable effect on 25(OH)D change. Higher doses can produce higher levels, but the relationship is not linear.

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

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

Dietary modulators of statin efficacy in cardiovascular disease and cognition

Cardiovascular disease remains the leading cause of morbidity and mortality in the United States and other developed countries, and is fast growing in developing countries, particularly as life expectancy in all parts of the world increases. Current recommendations for the prevention of cardiovascular disease issued jointly from the American Academy of Cardiology and American Heart Association emphasize that lifestyle modification should be incorporated into any treatment plan, including those on statin drugs. However, there is a dearth of data on the interaction between diet and statins with respect to additive, complementary or antagonistic effects. This review collates the available data on the interaction of statins and dietary patterns, cognition, genetics and individual nutrients, including vitamin D, niacin, omega-3 fatty acids, fiber, phytochemicals (polyphenols and stanols) and alcohol. Of note, although the available data is summarized, the scope is limited, conflicting and disparate. In some cases it is likely there is unrecognized synergism. Virtually no data are available describing the interactions of statins with dietary components or dietary pattern in subgroups of the population, particularly those who may benefit most were positive effects identified. Hence, it is virtually impossible to draw any firm conclusions at this time. Nevertheless, this area is important because were the effects of statins and diet additive or synergistic harnessing the effect could potentially lead to the use of a lower intensity statin or dose.

25-hydroxyvitamin D and parathyroid hormone levels do not predict changes in carotid arterial stiffness: the Multi-Ethnic Study of Atherosclerosis

OBJECTIVE

To evaluate the impact of vitamin D and parathyroid hormone (PTH) on longitudinal changes in arterial stiffness.

APPROACH AND RESULTS

Distensibility coefficient and Young's elastic modulus of the right common carotid artery were evaluated at baseline and after a mean (SD) of 9.4 (0.5) years in 2580 Multi-Ethnic Study of Atherosclerosis (MESA) participants. Cross-sectional and longitudinal associations were evaluated using multivariable linear regression and analysis of covariance. At baseline, participants were 60.1 (9.4) years old (54% female; 26% black, 20% Hispanic, 14% Chinese). Mean annualized 25(OH)D was <20 ng/dL in 816 participants, and PTH was >65 pg/dL in 285 participants. In cross-sectional analyses, low 25(OH)D (<20 ng/mL) was not associated with stiffer arteries after adjustment for cardiovascular disease risk factors (P>0.4). PTH >65 pg/mL was associated with stiffer arteries after adjustment for cardiovascular disease risk factors, other than systolic blood pressure (distensibility coefficient: β=-2.4×10(-4) mm Hg(-1), P=0.003; Young's elastic modulus: β=166 mm Hg, P=0.01); however, after adjustment for systolic blood pressure, these associations no longer were statistically significant. Longitudinal arterial stiffening was associated with older age (P<0.0001), higher systolic blood pressure (P<0.008), and use of antihypertensive medications (P<0.006), but not with 25(OH)D or PTH (both P>0.1).

CONCLUSIONS

Carotid arterial stiffness is not associated with low 25(OH)D concentrations. Cross-sectional associations between arterial stiffness and high PTH were attenuated by systolic blood pressure. After nearly a decade of follow-up, neither baseline PTH nor 25(OH)D concentrations were associated with progression of carotid arterial stiffness.

Investigation of serum bisphenol A, vitamin D, and parathyroid hormone levels in patients with obstructive sleep apnea syndrome

Obstructive sleep apnea syndrome (OSAS) is a common health problem, and associated with obesity, metabolic syndrome (MetS), and diabetes. Growing evidence shows that 25-hydroxyvitamin-D3 (25-OH-D) insufficiency and high parathyroid hormone (PTH) levels may be correlated to glucose intolerance, MetS, obesity, and cardiovascular abnormalities similar to OSAS. Bisphenol A (BPA) is an endocrine disruptor agent which exerts a wide variety of metabolic effects. It has estrogenic activity and its exposure may contribute to weight gain, obesity, impaired glucose metabolism, and the development of diabetes, also similar to OSAS. The aim of this study is to investigate the relationships between OSAS and serum BPA, 25-OH-D, and PTH levels. This study enrolled 128 subjects, with all of the OSAS patients having been diagnosed by polysomnography. The 128 subjects were divided into three groups: a control (n = 43), a moderate OSAS (n = 23) (AHI = 15-30), and a severe OSAS groups (n = 62) (AHI > 30). The serum BPA, 25-OH-D, and PTH levels for each subject were analyzed. 25-OH-D was lower in both OSAS groups, and PTH was higher in the OSAS groups than in the control subjects. The BPA levels were higher in the severe OSAS group than the moderate OSAS and control. There was a positive correlation between the BPA and body mass index, and a negative correlation between the 25-OH-D and BPA levels in all of the individuals. OSAS is related to high BPA and PTH levels, and low vitamin D levels. There is a positive association between BPA levels and OSAS, and the severity of OSAS. These results suggest that the BPA levels may have a role in the pathogenesis of OSAS.

Vitamin D deficiency and coronary artery disease: a review of the evidence

Coronary artery disease remains the leading cause of death in developed countries despite significant progress in primary prevention and treatment strategies. Older patients are at particularly high risk of poor outcomes following acute coronary syndrome and impaired nutrition, including low vitamin D levels, may play a role. The extraskeletal effects of vitamin D, in particular, its role in maintaining a healthy cardiovascular system are receiving increased attention. Longitudinal studies have demonstrated increased cardiovascular mortality and morbidity associated with vitamin D deficiency. Low vitamin D levels have been linked to inflammation, higher coronary artery calcium scores, impaired endothelial function and increased vascular stiffness. However, so far, few randomized controlled trials have investigated the potential benefits of vitamin D supplementation in preventing cardiovascular events, and most available trials have tested low doses of supplementation in relatively low-risk populations. Whether vitamin D supplementation will be beneficial among patients with coronary artery disease, including high risk older patients presenting with acute coronary syndrome, is unknown and warrants further investigation.

Relation of low vitamin D to nonvalvular persistent atrial fibrillation in Chinese patients

BACKGROUND

Low vitamin D status has been associated with increased risk of cardiovascular disease. Atrial fibrillation (AF) is the most common cardiac arrhythmia. We evaluated the association between low vitamin D and AF.

METHODS

We analyzed data from 162 Chinese patients with nonvalvular persistent AF and no other cardiovascular disease whose serum 25-hydroxyvitamin D [25(OH)D] levels were measured in our hospital (AF group). Healthy subjects without AF who underwent health screening at our hospital served as controls (non-AF group, n = 160). 25(OH)D was measured by chemiluminescence assay.

RESULTS

The serum 25(OH)D level was significantly lower in the AF group than in the non-AF group (18.5 ± 10.3 vs 21.4 ± 10.7 ng/mL, P < 0.05). The high-sensitivity C-reactive protein (hsCRP) level was significantly higher in the AF group than in the non-AF group (0.35 ± 0.19 vs 0.2 ± 0.17 mg/dL, P < 0.01). The average left atrial diameter was significantly larger in the AF group than in the non-AF group (P < 0.01). The serum 25(OH)D level showed a negative correlation with left atrial diameter, hsCRP level, and pulmonary artery systolic pressure. Logistic regression analysis identified that 25(OH)D was related to AF. Patients whose vitamin D levels were in the lowest 25(OH)D category (<20 ng/mL) were more often in the AF group, with their incidence about twofold higher than those in the highest 25(OH)D category (>30 ng/mL).

CONCLUSIONS

Low vitamin D levels are associated with AF. It may be involved in its development.

Vitamin D status and its relationship with metabolic markers in persons with obesity and type 2 diabetes in the UAE: a cross-sectional study

AIM

To report vitamin D status and its impact on metabolic parameters in people in the United Arab Emirates with obesity and type 2 diabetes (T2D).

METHODOLOGY

This cross-sectional study included 309 individuals with obesity and T2D who were randomly selected based on study criteria. Serum concentrations of 25-hydroxy vitamin D (s-25(OH)D), calcium, phosphorus, parathyroid hormone, alkaline phosphatase, glycemic profile, and cardiometabolic parameters were assessed in fasting blood samples, and anthropometric measurements were recorded.

RESULTS

Vitamin D deficiency (s-25(OH)D < 50 nmol/L) was observed in 83.2% of the participants, with a mean s-25(OH)D of 33.8 ± 20.3 nmol/L. Serum 25(OH)D correlated negatively (P < 0.01) with body mass index, fat mass, waist circumference, parathyroid hormone, alkaline phosphatase, triglycerides, LDL-cholesterol, and apolipoprotein B and positively (P < 0.01) with age and calcium concentration. Waist circumference was the main predictor of s-25(OH)D status. There was no significant association between serum 25(OH)D and glycemic profile.

CONCLUSION

There is an overwhelming prevalence of vitamin D deficiency in our sample of the Emirati population with obesity and T2D. Association of s-25(OH)D with body mass index, waist circumference, fat mass, markers of calcium homeostasis and cardiometabolic parameters suggests a role of vitamin D in the development of cardiometabolic disease-related process.