Non-linear associations between serum 25-OH vitamin D and indices of arterial stiffness and arteriosclerosis in an older population

Vitamin D and ischemic stroke - Association, mechanisms, and therapeutics

Confronting the rising tide of ischemic stroke and its associated mortality and morbidity with ageing, prevention and acute management of ischemic stroke is of paramount importance. Mounting observational studies have established a non-linear association of vitamin D status with cardiovascular diseases, including ischemic stroke. Paradoxically, current clinical trials fail to demonstrate the cardiovascular benefits of vitamin D supplementation. We aim to update recent clinical and experimental findings on the role of vitamin D in the disease course of ischemic stroke, from its onset, progression, recovery, to recurrence, and the established and alternative possible pathophysiological mechanisms. This review justifies the necessities to address stroke etiological subtypes and focus on vitamin D-deficient subjects for investigating the potential of vitamin D supplementation as a preventive and therapeutic approach for ischemic stroke. Well-powered clinical trials are warranted to determine the efficacy, safety, timing, target individuals, optimal dosages, and target 25OHD concentrations of vitamin D supplementation in the prevention and treatment of ischemic stroke.

Analysis of the Dose-Response Relationship Between the International Normalized Ratio and Hepatic Encephalopathy in Patients With Liver Cirrhosis Using Restricted Cubic Spline Functions

Background

The International Normalized Ratio (INR) is significantly associated with Hepatic Encephalopathy (HE) in patients with liver cirrhosis. However, the dose-response relationship between continuous INR changes and HE risk has not been clearly defined. Thus, our goal was to explore the continuous relationship between HE and INR among patients hospitalized with liver cirrhosis and to evaluate the role of the INR as a risk factor for HE in these patients.

Methods

A total of 6,266 people were extracted from the Big Data Platform of the Medical Data Research Institute of Chongqing Medical University. In this study, unconditional logistic regression and restricted cubic spline (RCS) model were used to analyze the dose-response association of INR with HE. Alcoholic liver disease, smoking status, and drinking status were classified for subgroup analysis.

Results

The prevalence of HE in the study population was 8.36%. The median INR was 1.4. After adjusting for alcoholic liver disease, age, smoking status, drinking status, total bilirubin, neutrophil percentage, total hemoglobin, aspartate aminotransferase, serum sodium, albumin, lymphocyte percentage, serum creatinine, red blood cell, and white blood cell, multivariate logistic regression analysis revealed that INR ≥ 1.5 (OR = 2.606, 95% CI: 2.072–3.278) was significantly related to HE risk. The RCS model showed a non-linear relationship between the INR and HE (non-linear test, χ² = 30.940, P < 0.001), and an increased INR was an independent and adjusted dose-dependent risk factor for HE among patients with liver cirrhosis.

Conclusion

This finding could guide clinicians to develop individualized counseling programs and treatments for patients with HE based on the INR risk stratification.

Analysis of angiographic characteristics and intervention of vitamin D in type 2 diabetes mellitus complicated with lower extremity arterial disease

AIMS

Previous studies have suggested that type 2 diabetes mellitus with lower extremity arterial disease is related to 25-hydroxyvitamin D deficiency. The purpose of this study is to explore the relation between vitamin D supplementation and the characteristics of type 2 diabetes mellitus complicated with lower extremity arterial disease.

METHODS

The clinical data of 514 patients and 148 healthy subjects treated in the First Hospital of Lanzhou University from January 2012 to June 2019 were collected, including the clinical data, ankle-brachial index, and medical records of lower limb artery angiography. We divided the patients into control group (NC group), type 2 diabetes mellitus group (DM group), lower extremity artery disease in type 2 diabetes mellitus without vitamin D supplement group (DM1 group) and lower extremity artery disease in type 2 diabetes mellitus with vitamin D supplement group (DM2 group). The level of serum 25(OH)D was analyzed and the characteristics of arterial lesions of lower extremities were compared by DSA arteriography in DM1 and DM2 group, respectively.

RESULTS

Compared with the NC group, serum 25(OH)D level decreased in DM group (25.39 ± 4.94 ng/mL vs 19.43 ± 5.98 ng/mL) and significantly decreased in DM1 and DM2 group (14.22 ± 5.64 ng/mL vs 17.36 ± 6.25 ng/mL). However, the level of serum 25(OH)D in the DM2 group was higher than that in the DM1 group. Compared with the DM1 group, the disease rate of the inferior knee artery (65% vs 39.3%) and occlusion rate (11.5% vs 3.7%)were decreased in the DM2 group (P < 0.05). Logistic stepwise regression analysis showed that serum 25(OH)D level was a risk factor for lower extremity arterial disease in patients with type 2 diabetes mellitus (OR = 0.898,95%CI = 0.856-0.942).

CONCLUSIONS

The serum level of 25(OH)D in patients with type 2 diabetes mellitus complicated with lower extremity arterial disease is decreased, and level of 25 (OH) D is related to stenosis and occlusion rate, especially in inferior genicular artery in T2DM complicated with LEAD. A high level of 25(OH)D may be a protective factor in type 2 diabetes with lower extremity arterial disease.

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

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

A 3 year post-intervention follow-up on mortality in advanced heart failure (EVITA vitamin D supplementation trial)

Aims

Vitamin D supplementation is widely used in the clinical setting, but its effects on mortality and cardiovascular outcomes in patients with heart failure are unclear. This paper reports outcome data that were collected during follow‐up of 3 years after closure of the EVITA trial (a 3 year randomized, placebo‐controlled, intervention study with 4000 IU vitamin D daily in patients with advanced heart failure), to capture potential latency effects of vitamin D supplementation on clinical outcomes.

Methods and results

The prespecified primary endpoint was overall mortality. Secondary endpoints included hospitalization, mechanical circulatory support implantation, high urgent listing for heart transplantation, and heart transplantation. For group comparisons, we used Cox regression models with a time‐dependent categorical covariate. The calculated net difference in circulating 25‐hydroxyvitamin D between the vitamin D and placebo groups dropped from 60.9 nmol/L at the end of the active study period to 3.2 nmol/L at the end of the post‐intervention period. During the entire 6 year period, 73 patients (36.5%) died in the placebo group and 76 (38.8%) in the vitamin D group. Out of these 149 patients, 36 and 39 died during the first 3 years, and 37 and 37 during the second 3 years, respectively. The hazard ratio (HR) for mortality in the vitamin D versus the placebo group was 1.06 [95% confidence interval (CI): 0.68–1.66] for the first 3 years and 1.07 (95% CI: 0.68–1.70) for the 3 year post‐intervention follow‐up. Compared with the placebo group, the HRs for hospitalization and for mechanical circulatory support implant were significantly higher in the vitamin D group during vitamin D supplementation (HR = 1.31, 95% CI: 1.01–1.68 and HR = 2.01, 95% CI: 1.08–3.76, respectively) but not after vitamin D discontinuation (HR = 1.10, 95% CI: 0.62–1.94 and HR = 0.99, 95% CI: 0.38–2.56, respectively). There was no significant time‐dependent effect on the risk of high urgent listing for heart transplantation and heart transplantation.

Conclusions

No beneficial latency effects of vitamin D supplementation on overall mortality could be demonstrated. Instead, the disappearance of unfavourable findings in the vitamin D group (higher HRs for hospitalization and for mechanical circulatory support implant) after vitamin D discontinuation supports the assumption of adverse vitamin D effects on the cardiovascular system at doses of 4000 IU daily.

[Influencing factors for the clinical effect of bronchoalveolar lavage in children with Mycoplasma pneumoniae pneumonia and atelectasis]

OBJECTIVE

To study the influencing factors for the clinical effect of bronchoalveolar lavage (BAL) in children with Mycoplasma pneumoniae pneumonia (MPP) and atelectasis.

METHODS

A total of 75 children with MPP and atelectasis were divided into a good response group with 51 children and a poor response group with 24 children according to the clinical effect of BAL treatment. LASSO logistic regression analysis was used to investigate the factors influencing the clinical effect of BAL treatment. The receiver operating characteristic (ROC) curve and restricted cubic spline model analysis were used to evaluate the value of the course of the disease at the time of BAL treatment in predicting the clinical effect of BAL treatment.

RESULTS

Compared with the good response group, the poor response group had a significantly lower percentage of lymphocytes in bronchoalveolar lavage fluid, a significantly higher proportion of children with atelectasis of two or more lung lobes or stenosis of the bronchial cavity or opening caused by inflammation, and a significantly longer course of the disease at the time of BAL treatment and azithromycin treatment (P<0.05). The LASSO logistic regression analysis showed that a prolonged course of the disease at the time of BAL treatment (OR=1.23), atelectasis of two or more lung lobes (OR=11.99), and stenosis of the bronchial cavity or opening caused by inflammation (OR=5.31) were independent risk factors for poor clinical effect of BAL treatment (P<0.05). The ROC curve analysis showed that the course of disease of ≥11.5 days at the time of BAL treatment suggested a poor clinical effect of BAL treatment, with a sensitivity of 91.7% and a specificity of 54.9%. The restricted cubic spline model analysis showed that there was a non-linear dose-response relationship between the course of disease at the time of BAL treatment and the clinical effect of BAL treatment (P<0.05).

CONCLUSIONS

Early BAL treatment may have a good clinical effect in children with MPP and atelectasis. Atelectasis of two or more lung lobes and inflammation-induced stenosis of the bronchial cavity or opening shown under bronchoscope may indicate a poor clinical effect of BAL treatment.

The Association between Cardiovascular Disease Risk Factors and 25-Hydroxivitamin D and Related Analytes among Hispanic/Latino Adults: A Pilot Study

Although the association of vitamin D levels with cardiovascular risk profiles among Hispanics/Latinos has been studied, little is known about this association among Hispanics/Latinos with chronic conditions. This pilot study determined serum vitamin D and parathyroid hormone (PTH) levels in a sample of participants from the University of Illinois at the Chicago Cohort of Patients, Family and Friends (UIC Cohort) and examined their association with traditional cardiovascular disease risk factors. From July 2012 to June 2016, the UIC Cohort study enrolled and conducted clinical examinations on men and women ages 18 years and older, who had one or more diagnosed chronic diseases/conditions (excluding cancer). This pilot study sample included 40 participants from the six main Hispanic/Latino background groups in the United States, namely Dominican, Cuban, Puerto Rican, Mexican, Central American, and South American, and were grouped by Caribbean or mainland origin. No substantial differences were noted in the vitamin D-related measures by Hispanic/Latino background, but the PTH levels were somewhat higher in the Caribbean vs. mainland group (43.0 ± 4.6 vs. 38.6 ± 2.7 pg/mL). The associations between selected CVD risk factors (systolic and diastolic blood pressure (SBP, DBP), total cholesterol, glucose) and PTH and vitamin D-related analytes were investigated using interval-censored multivariate regression models adjusted for age, sex, percent body fat, serum albumin/calcium, and Hispanic/Latino background. A negative association between total 25[OH]D and blood pressure was corroborated (SBP: β = -1.2, 95%CI = -2.0, -0.3; DBP: β = -0.7, 95% CI = -1.2, -0.1), whereas a positive association with total cholesterol was observed (β = 1.9, 95% CI = 0.02, 3.7). Levels of 1, 25[OH]2D were not associated with CVD risk factors, whereas 24, 25[OH]2D3 was associated with blood pressure (SBP: β = -13.0, 95% CI = -20.7, -5.2; DBP: β = -6.3, 95% CI = -11.6, -1.0). Estimated free 25[OH]D was inversely associated with both SBP (β = -3.5, 95% CI = -6.1, -0.9) and DBP (β = -2.1, 95% CI = -3.8, -0.3). Similarly, calculated bioavailable 25[OH]D was inversely associated with both SBP (β = -9.2, 95% CI = -15.9, -2.4) and DBP(β = -5.3, 95% CI = -9.8, -0.8). In conclusion, a negative association between 25[OH]D with BP was observed and a positive association with lipids is suggested. Due to the small sample size, most associations did not reach statistical significance.

Links between High-Sensitivity C-Reactive Protein and Pulse Wave Analysis in Middle-Aged Patients with Hypertension and High Normal Blood Pressure

Arterial stiffness and arterial age provide valuable prognostic cardiovascular information. The present study aimed at assessing the levels of vitamin D, high-sensitivity C-reactive protein (hsCRP), low-density lipoprotein cholesterol (LDL), and oxidized LDL (oxLDL) in a group of middle-aged hypertensive patients and their relationship with pulse wave velocity (PWV), central blood pressure, and early arterial aging (EAA), respectively. A total of 56 patients, aged 48 ± 6 years, 57% males, with hypertension and high normal blood pressure (HNBP), were investigated using a Mobile-O-Graph, to assess central and peripheral blood pressure, PWV, and arterial age. Additionally, hsCRP, LDL, oxLDL, and 25-hydroxy vitamin D3 were assessed. PWV, 25-hydroxy vitamin D3, hsCRP, oxLDL, and LDL levels were 7.26 ± 0.69 m/s, 25.99 ± 11.17 microg/l, 0.48 ± 0.44 mg/dl, 261.37 ± 421 ng/ml, and 145.73 ± 39.53 mg/dl, respectively. Significant correlations were obtained between oxLDL and pulse pressure amplification (rS = -0.347, p = 0.028) and between hsCRP and LDL levels with PWV and EAA, respectively. ROC curve analysis revealed that hsCRP is a sensitive and specific predictor of EAA and increased PWV values. Concluding, vitamin D deficiency and increased hsCRP and LDL values are very common, and high oxidized LDL is related to pulse pressure amplification in patients with elevated blood pressure. Vitamin D level and high-sensitivity C-reactive protein and LDL provide valuable information in middle-aged hypertensive and HNBP patients related to arterial stiffness and early arterial aging, but only hsCRP is a sensitive predictor of EAA and PWV.

Obesity, dynapenia and high cardiovascular risk co-exist in post-liver transplant setting: results of a cross-sectional study

BACKGROUND

Cardiovascular disease is a major cause of death in post-liver transplantation (LT). The aim of this study was to evaluate LT patients as to the carotid intima-media thickness (CIMT) and its association with nutritional status, dietary intake, metabolic profile and cardiovascular risk factors.

METHODS

In this cross-sectional study, adult patients with more than 12 months of post-transplant follow-up underwent clinical, laboratory, functional and nutritional evaluation by 3-day-diet-record, anthropometry and dynamometry. CIMT was evaluated by Doppler ultrasonography.

RESULTS

Sixty-nine post-LT patients [males 61%, median of age 59 (51-64) years were included; median time post-liver transplantation 2.8 (1.4-6.3) years]. High prevalence of malnutrition was found (45% of arm muscle area < p15 and 71% of handgrip strength < p30). Excess weight was present in 72% of patients, body mass index ≥ 30 kg/m² in 35% and metabolic syndrome in 51%. Abnormal CIMT was found in 54% of the sample. Patients with abnormal CIMT presented higher cardiovascular risk Score, LDL cholesterol, higher prevalence of high-sensitive C-reactive protein ≥ 1 mg/L and higher intake of saturated and trans fatty acids (P < 0.05 for all).

CONCLUSIONS

Abnormal IMT was commonly found in LT patients presenting at the same time with overweight and dynapemia. These results were associated with higher LDL-cholesterol levels, high-sensitive C-reactive protein ≥ 1 mg/L and higher intake of saturated and trans fatty acids. Preventive measures, including dietary advice, are required for all post-liver transplantation patients to minimize cardiovascular risk.

Association between body mass index and fatty liver risk: A dose-response analysis

Body mass index (BMI) is associated with fatty liver risk, however, the dose-response relationship between continuous BMI changes and fatty liver risk has not been clearly defined. In this study, a cross-sectional study was conducted and a total of 3202 individuals were included. Unconditional logistic regression and restricted cubic spline model were used to analyze the dose-response association of BMI with fatty liver risk. After adjusting for confounding factors (age, gender, hypertension, total cholesterol, triglycerides, glucose, high-density lipoprotein, low-density lipoprotein, uric acid, homocysteine, creatinine, aspartate aminotransferase and alanine transaminase), overweight (OR = 3.55, 95% CI: 2.49–5.06, P = 2.79 × 10⁻¹²), obesity (OR = 7.59, 95% CI: 4.91–11.71, P = 6.56 × 10⁻²⁰) were significantly related to fatty liver risk. Stratified by gender (male/female), age (<50 years/≥50 years), prevalence of hypertension (yes/no), the above association was still significant (P = 0.004 or lower). In dose-response analysis, BMI was statistically significantly associated with fatty liver risk in a nonlinear fashion (approximately J-shaped fashion, P_nonlinearity = 1.71 × 10⁻⁴ or lower) in the total population and all subgroups mentioned above. Findings from this dose-response analysis suggest that higher BMI (overweight/obesity) is an independent, dose-dependent risk factor for fatty liver, and prevention of fatty liver focusing on continuous changes in BMI should be noted.

Vitamin D and cardiovascular disease

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

Association of Serum Vitamin D Level and Carotid Atherosclerosis: A Systematic Review and Meta-analysis

Vitamin D deficiency is associated with an increased risk of subclinical atherosclerosis. To explore the potential link of the serum vitamin D level with carotid atherosclerosis, this meta-analysis assessed the correlation between vitamin D and carotid intima-media thickness as well as carotid atherosclerotic plaque. PubMed, Embase, Web of Science, and Cochrane Library databases were searched until the end of March 2017. Clinical studies investigating the relationship between vitamin D and carotid atherosclerosis were included. The outcome data were extracted according to the inclusion criteria and pooled for an effect estimate by a random-effects model. Of the 506 initially retrieved studies, 11 studies involving a total of 16,434 participants were included in the meta-analysis. Newcastle-Ottawa Quality Assessment Scale scores suggested that the included studies were of high quality. The pooled effects estimate showed that the serum vitamin D level was negatively associated with carotid atherosclerosis (odds ratio, 0.95; 95% confidence interval [CI], 0.93-0.96), with substantial heterogeneity among the individual studies (I²  = 54%). Furthermore, a subgroup analysis suggested that hypovitaminosis D was associated with an 0.85-fold decrease in the odds of having a higher carotid intima-media thickness (95% CI, 0.76-0.96; P < .05; I²  = 69%). Additionally, the pooled analysis also indicated that the serum vitamin D level was a protective factor against increased carotid plaque (odds ratio, 0.95; 95% CI, 0.93-0.97; P < .05; I²  = 29%). Funnel plots and the Egger regression test showed the absence of a publication bias. In this meta-analysis, we comprehensively revealed a close link between vitamin D deficiency and carotid atherosclerosis. Patients with hypovitaminosis D might have extra requirements for preventive and therapeutic measures against early atherosclerosis, thus reducing the cardiovascular disease risk in the long term.

Associations between vitamin D status and atherosclerosis among Inuit in Greenland

BACKGROUND AND AIMS

Low levels of vitamin D are suspected to be a risk factor for cardiovascular disease and atherosclerosis. The aim of this study was to assess the prevalence of subclinical atherosclerosis among Inuit in Greenland, and to evaluate the association with vitamin D status. We hypothesized that low vitamin D status could be associated with higher carotid intima-media thickness (IMT) as a marker of atherosclerosis.

METHODS

756 adults from the Inuit Health in Transition (IHIT) study carried out in Greenland in the period 2005-2010 were included. A blood sample donated in 1987 was available for a sub-sample of 102 individuals. Serum 25(OH)D3 from the IHIT study and the 1987 survey was used as a measure of vitamin D status. IMT measurements were conducted by ultrasound scanning. The prevalence of atherosclerosis was estimated, and the association between serum 25(OH)D3 and IMT measurements was examined by linear regression.

RESULTS

The overall prevalence of subclinical atherosclerosis was 20.1% (n = 152). The linear regression analyses indicated a weak positive association between serum 25(OH)D3 level and IMT measurements from the IHIT study, though not statistically significant after adjustment for potential confounders (β = 0.35% per 10 nmoL/L 25(OH)D3, p = 0.06). Linear regression analyses of the association between serum 25(OH)D3 level in the 1987 survey and IMT measurements also indicated a positive, though not statistically significant, association after adjustment (β = 0.07% per 10 nmoL/L 25(OH)D3, p = 0.86).

CONCLUSIONS

Our findings did not support the hypothesis of an association between low vitamin D levels and risk of atherosclerosis.

Crosstalk between Vitamins A, B12, D, K, C, and E Status and Arterial Stiffness

Arterial stiffness is associated with cardiovascular risk, morbidity, and mortality. The present paper reviews the main vitamins related to arterial stiffness and enabling destiffening, their mechanisms of action, providing a brief description of the latest studies in the area, and their implications for primary cardiovascular prevention, clinical practice, and therapy. Despite inconsistent evidence for destiffening induced by vitamin supplementation in several randomized clinical trials, positive results were obtained in specific populations. The main mechanisms are related to antiatherogenic effects, improvement of endothelial function (vitamins A, C, D, and E) and metabolic profile (vitamins A, B12, C, D, and K), inhibition of the renin-angiotensin-aldosterone system (vitamin D), anti-inflammatory (vitamins A, D, E, and K) and antioxidant effects (vitamins A, C, and E), decrease of homocysteine level (vitamin B12), and reversing calcification of arteries (vitamin K). Vitamins A, B12, C, D, E, and K status is important in evaluating cardiovascular risk, and vitamin supplementation may be an effective, individualized, and inexpensive destiffening therapy.

Vitamin D Metabolism and the Implications for Atherosclerosis

Vitamin D levels and metabolism may play a role in the pathogenesis and treatment of atherosclerosis and subsequent cardiovascular health. Herein, we discuss both normal and disordered vitamin D metabolism as it pertains to atherosclerosis, and we review major clinical trials regarding vitamin D levels and effects of supplementation. Although there are no official recommendations for vitamin D as it applies to atherosclerosis, it is clear that these two entities are linked. Further study of the complex association between vitamin D and atherosclerosis, as well as the effects of supplementation, are recommended.

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

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

Effectiveness of Vitamin D Supplementation for Cardiovascular Health Outcomes

There is a plausible physiological theory, supported by many observational studies, that vitamin D supplementation should be effective for improving cardiovascular end points, such as blood pressure (BP), large artery stiffness, atherosclerosis, endothelial function and clinical events. However, results from randomised controlled trials (RCTs) have been inconsistent. In this review, we evaluated the evidence regarding the effectiveness of vitamin D supplementation for cardiovascular surrogate and hard clinical end points. RCTs were assessed in terms of sample size, duration of supplementation, baseline vitamin D level inclusion criteria (i.e., absence of vitamin D deficiency), dosage of vitamin D and population under investigation. Forty-five RCTs were identified. Eight RCTs with BP and 6 RCTs with large artery stiffness as the end points were found to comply with guidelines for the optimal design of clinical trials evaluating nutrient effects. Only 2 of the RCTs with an optimal design were effective in decreasing BP with vitamin D supplementation, although these were of moderate sample size (<150) and very short duration (8 weeks for both), whilst no RCT was effective in reducing large artery stiffness. Similar results were observed for atherosclerotic and endothelial function markers as end points. Only 1 RCT reported cardiovascular events as an end point and found neither increased nor decreased incident cardiovascular events over 7 years of follow-up. In conclusion, results from published RCTs indicate that vitamin D supplementation is ineffective in improving cardiovascular health among various patient populations, including in the presence or absence of vitamin D deficiency.

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

Background

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

Methods

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

Results

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

Conclusions

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

The cross-sectional relationships of dietary and serum vitamin D with cardiometabolic risk factors: Metabolic components, subclinical atherosclerosis, and arterial stiffness

OBJECTIVE

There has been increasing interest in non-skeletal interactions between vitamin D insufficiency, which is common, and cardiovascular event and cardiovascular disease (CVD) risk factors.

METHODS

To evaluate cross-sectional associations between dietary and serum vitamin D status and metabolic abnormalities and arterial changes among 1054 adults aged ≥40 y (404 men and 650 women) in a rural area of South Korea. Study subjects were divided into three groups according to dietary vitamin D intake (tertiles) measured by food frequency questionnaire and serum 25(OH)D levels (≤20, 21-29, and ≥30 ng/mL). Metabolic components (blood pressure, lipid profiles, and glycemic index) and arterial changes (brachial ankle pulse wave velocity [baPWV] and carotid artery intima-media wall thickness [cIMT]) were measured.

RESULTS

Dietary vitamin D was inversely associated with diastolic blood pressure (DBP) and baPWV among men, but the association disappeared after multinutrient supplement users were excluded. Among women, there was an inverse association between dietary vitamin D and triacylglycerol (TG) levels. However, serum 25(OH)D showed a significant positive relationship with HDL cholesterol in both men and women, while a positive linear trend or nonlinear trend with serum 25(OH)D levels was shown in TG levels among men and in systolic blood pressure (SBP), DBP, total cholesterol, and baPWV among women. The positive relationship between serum 25(OH)D with baPWV disappeared after adjustment for blood pressure.

CONCLUSIONS

Serum 25(OH)D may be favorably related to HDL cholesterol. However, serum 25(OH)D may not favorably related to subclinical atherosclerosis and arterial stiffness measured by cIMT and baPWV. The positive relationship between 25(OH)D and baPWV is likely to be mediated by blood pressure.

BMI and Body Fat Mass Is Inversely Associated with Vitamin D Levels in Older Individuals

OBJECTIVE

To assess the association between obesity (measured by Body Mass Index (BMI) and fat percentage) and serum 25(OH)D levels in older persons.

DESIGN

Cross-sectional analysis of data from 'the B-PROOF study' (B-vitamins for the Prevention Of Osteoporotic Fractures).

PARTICIPANTS

2842 participants aged 65 years and older.

MEASUREMENTS

BMI and fat percentage, measured by Dual Energy X-ray, and serum 25(OH)D levels.

RESULTS

Mean age was 74 years (6.5 SD), with 50% women. Mean serum 25(OH)D levels were 55.8 nmol/L (25 SD). BMI and total body fat percentage were significant inversely associated with serum 25(OH)D levels after adjustment for confouders (β-0.93; 95% CI [-1.15; -0.71], p<0.001 and β-0.84; 95% CI [-1.04; -0.64], p<0.001). This association was most prominent in individuals with a BMI in the 'overweight' and 'obesity' range (β -1.25 and -0.96 respectively) and fat percentage in the last two upper quartiles (β-1.86 and -1.37 respectively).

CONCLUSION

In this study, higher BMI and higher body fat percentage were significantly associated with lower serum 25(OH)D levels in older persons. This association was particularly present in individuals with overweight, and higher fat percentages, suggesting that these persons are at increased risk of vitamin D insufficiency.

The Role of Vitamin D in Diabetes and Cardiovascular Disease: An Updated Review of the Literature

The dietary reference values for Vitamin D were set primarily considering its role in bone health, but with the discovery of Vitamin D receptors throughout body tissues, new links with other health conditions are now studied, such as for diabetes and cardiovascular diseases (CVD). This paper shall analyze and examine all new research studies carried out, especially in 2013–2015 regarding diabetes mellitus (DM) and cardiovascular diseases (CVD). Vast research has been carried out to establish strong relationship between Vitamin D serum levels, supplementation, diabetes, and CVD. However, the results from researches identified in this paper are disputable. Benefits of Vitamin D adequate levels were recognized from gestational period until later in disease development such as diabetes and/or CVD, but since not all studies are in agreement further investigation is suggested. Researches conducting large randomized controlled trials, exploring range of supplement doses, with variable baseline serum Vitamin D levels, and inclusion of array of associated parameters, are still required to conduct large-scale analysis and draw conclusion as a risk factor. Until then it is possible to conclude that maintenance of serum Vitamin D levels holds advantageous aspects in diabetic and cardiovascular conditions, and people should strive to attain them.