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Vitamin D supplementation does not improve CVD risk factors in vitamin D-insufficient subjects.

ABSTRACT: OBJECTIVE:Low serum 25(OH)D levels are associated with cardiovascular disease (CVD) and some of its risk factors. However, in interventional studies, the effects of vitamin D supplementation have been uncertain, possibly due to inclusion of vitamin D-sufficient subjects. Our aim was therefore to examine effects of vitamin D supplementation on CVD risk factors in vitamin D-insufficient subjects. DESIGN:Double-blinded randomized controlled trial. METHODS:A 4-month interventional study with high-dose vitamin D (100,000?IU loading dose, followed by 20,000?IU/week) or placebo with measurements of blood pressure, lipids (total-, LDL- and HDL-cholesterol, triglycerides, apolipoproteins A1 and B), and glucose metabolism parameters (blood glucose, HbA1c, serum human receptors for advanced glycation end products (sRAGE), insulin, C-peptide and HOMA-IR). RESULTS:A total of 422 subjects with mean serum 25(OH)D level 34?nmol/L were included, with 411 subjects completing the study. Serum 25(OH)D levels increased with 56?nmol/L and decreased with 4?nmol/L in the vitamin D and placebo group, respectively. We found no statistically significant differences between the two groups in any of the measured CVD risk factors, except for a minor increase in sRAGE in the vitamin D group. Stratified analyses of subjects with low baseline serum 25(OH)D levels alone, or combined with blood pressure, lipid and HOMA-IR values above the median for the cohort, did not skew the results in favour of vitamin D supplementation. CONCLUSION:Supplementation with vitamin D in subjects with baseline vitamin D insufficiency does not improve CVD risk factor profile.

SUBMITTER: Kubiak J

PROVIDER: S-EPMC6000752 | biostudies-literature | 2018 Jun

REPOSITORIES: biostudies-literature

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Vitamin D supplementation does not improve CVD risk factors in vitamin D-insufficient subjects.

Kubiak Julia J Thorsby Per Medbøe PM Kamycheva Elena E Jorde Rolf R

Endocrine connections 20180515 6

<h4>Objective</h4>Low serum 25(OH)D levels are associated with cardiovascular disease (CVD) and some of its risk factors. However, in interventional studies, the effects of vitamin D supplementation have been uncertain, possibly due to inclusion of vitamin D-sufficient subjects. Our aim was therefore to examine effects of vitamin D supplementation on CVD risk factors in vitamin D-insufficient subjects.<h4>Design</h4>Double-blinded randomized controlled trial.<h4>Methods</h4>A 4-month interventio ...[more]

PMID: 29764903

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Project description:INTRODUCTION:Our previous study-level (aggregate data) meta-analysis suggested that vitamin D supplements may be beneficial for bone density specifically in children with vitamin D deficiency. However, the misclassification of vitamin D status inherent in study-level data means that the results are not definitive and cannot provide an accurate assessment of the size of any effect. Therefore, we propose to undertake an individual patient data (IPD) meta-analysis to determine whether the effect of vitamin D supplementation on bone density in children differs according to baseline vitamin D status, and to specifically estimate the effect of vitamin D in children who are vitamin D deficient. METHODS AND ANALYSIS:This study has been designed to adhere to the Preferred Reporting Items for Systematic Review and Meta-Analyses of IPD statement. We will include randomised placebo-controlled trials of vitamin D supplementation reporting bone density outcomes at least 6 months after the study commenced in children and adolescents (aged <20 years) without coexistent medical conditions or treatments causing osteoporosis. We will update the search of the original review to cover the period 2009-2017, using the same methods as the original review. Fully anonymised data on all randomised patients will be requested. Outcomes will be femoral neck, total hip, lumbar spine and proximal and distal forearm bone mineral density, and total body bone mineral content. A two-stage IPD meta-analysis will be used to examine the effect of baseline serum 25-hydroxyvitamin D (25(OH)D) on treatment effect for each bone density outcome. Restricted maximum likelihood will be used to estimate the random-effects meta-analysis models, with 95% CI for summary effects. Heterogeneity will be assessed by I2 and potential publication bias (small-study effects) and availability bias by funnel plots, Egger's test and Peter's test. ETHICS AND DISSEMINATION:Ethics approval will not be required as the data are to be used for the primary purpose for which they were collected and all original individual studies had ethics approval. Results of the IPD meta-analysis will be submitted for publication in a peer-reviewed journal. PROSPERO REGISTRATION NUMBER:CRD42017068772.

Project description:BackgroundVascular calcification, a risk factor for cardiovascular disease, is common among patients with CKD and is an independent contributor to increased vascular stiffness and vascular risk in this patient group. Vitamin K is a cofactor for proteins involved in prevention of vascular calcification. Whether or not vitamin K supplementation could improve arterial stiffness in patients with CKD is unknown.MethodsTo determine if vitamin K supplementation might improve arterial stiffness in patients in CKD, we conducted a parallel-group, double-blind, randomized trial in participants aged 18 or older with CKD stage 3b or 4 (eGFR 15-45 ml/min per 1.73 m2). We randomly assigned participants to receive 400 μg oral vitamin K2 or matching placebo once daily for a year. The primary outcome was the adjusted between-group difference in carotid-femoral pulse wave velocity at 12 months. Secondary outcomes included augmentation index, abdominal aortic calcification, BP, physical function, and blood markers of mineral metabolism and vascular health. We also updated a recently published meta-analysis of trials to include the findings of this study.ResultsWe included 159 randomized participants in the modified intention-to-treat analysis, with 80 allocated to receive vitamin K and 79 to receive placebo. Mean age was 66 years, 62 (39%) were female, and 87 (55%) had CKD stage 4. We found no differences in pulse wave velocity at 12 months, augmentation index at 12 months, BP, B-type natriuretic peptide, or physical function. The updated meta-analysis showed no effect of vitamin K supplementation on vascular stiffness or vascular calcification measures.ConclusionsVitamin K2 supplementation did not improve vascular stiffness or other measures of vascular health in this trial involving individuals with CKD.Clinical trial registry name and registration numberVitamin K therapy to improve vascular health in patients with chronic kidney disease, ISRCTN21444964 (www.isrctn.com).

Project description:Background: Cardiovascular disease (CVD) risk factors are associated with low serum 25 hydroxyvitamin D (25(OH)D) concentrations in observational studies; however, clinical trial findings are inconsistent. Objective: We assessed the effect of vitamin D supplementation and increased serum 25(OH)D concentrations on CVD risk factors in a systemic review and meta-analysis of randomized controlled trials (RCTs). Design: MEDLINE, CINAHL, EMBASE, and Google Scholar were searched for RCTs that evaluated vitamin D supplementation and cardiovascular outcomes [blood pressure, parathyroid hormone (PTH), serum high-sensitivity C-reactive protein (hs-CRP), total cholesterol, high and low density lipoprotein (HDL and LDL, respectively), triglycerides, peak wave velocity (PWV) and Augmentation Index (AI)] from 1992 through 2017. Meta-analysis was based on a random-effects model and inverse variance method to calculate standardized mean difference (SMD) as effect sizes, followed by a leave-one-out method for sensitivity analysis. Risk of publication bias was assessed using Cochrane checklist and Begg funnel plots. The systematic review is registered as CRD42015025346. Results: We identified 2341 studies from which 81 met inclusion criteria. The meta-analysis indicated a significant reduction in systolic blood pressure (SMD = -0.102 ± 0.04 mmHg, 95% confidence interval (CI), -0.20 to -0.03), diastolic blood pressure (SMD = -0.07 ± 0.03 mmHg, 95% CI, -0.14 to -0.006), serum PTH (SMD = -0.66 ± 0.08 ng/L, 95% CI, -0.82 to -0.49), hs-CRP (SMD = -0.20 ± 0.07 mg/L, 95% CI, -0.34 to -0.06), total cholesterol (SMD = -0.15 ± 0.06 mmol/L, 95% CI, -0.25 to -0.04), LDL (SMD = -0.10 ± 0.05 mmol/L, 95% CI, -0.20 to -0.003), triglycerides (SMD = -0.12 ± 0.06 mmol/L, 95% CI, -0.23 to -0.003) and a significant increase in HDL (SMD = 0.09 ± 0.04 mmol/L, 95% CI, 0.00 to 0.17) with vitamin D supplementation. These findings remained significant in sensitivity analyses for blood pressure, lipid profile, serum PTH, and serum hs-CRP. There was no significant effect of vitamin D supplementation on PWV (SMD = -0.20 ± 0.13 m/s, 95% CI, -0.46 to 0.06, p = 0.14) and AI (SMD = -0.09 ± 0.14%, 95% CI, -0.37 to 0.19, p = 0.52) for vitamin D supplemented groups. Conclusion: These findings suggest that vitamin D supplementation may act to protect against CVD through improving risk factors, including high blood pressure, elevated PTH, dyslipidemia, and inflammation.

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Vitamin D supplementation does not improve CVD risk factors in vitamin D-insufficient subjects.

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Vitamin D supplementation does not improve CVD risk factors in vitamin D-insufficient subjects.

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