1.
Effects of Vitamin D Supplementation on Lipid Profile in Adults with the Metabolic Syndrome: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.
AlAnouti, F, Abboud, M, Papandreou, D, Mahboub, N, Haidar, S, Rizk, R
Nutrients. 2020;(11)
Abstract
BACKGROUND Metabolic syndrome (MetS) increases the risk of cardiovascular disease, with atherogenic dyslipidemia being a major contributing factor. METHODS A systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement to assess whether vitamin D supplementation (VDS) alleviates dyslipidemia in adults with MetS. Scientific databases (PUBMED, MEDLINE, CINAHL, EMBASE, Cochrane Library, ClinicalTrials.gov, International Clinical Trials Registry Platform) and the gray literature were searched for randomized controlled trials of VDS, reporting on blood lipids. A narrative review, meta-analyses, sensitivity analyses, and appraisal of the risk of bias and overall quality of evidence produced were conducted. RESULTS Seven studies were included, and four were meta-analyzed. The risk of bias was generally low, and the final quality of evidence was low or very low. VDS, whether in high or low dose, significantly increased endline vitamin D blood levels; did not affect total, low-density, high-density cholesterol levels, and novel lipid-related biomarkers; yet, significantly increased triglycerides (TG) levels compared with placebo (MD: 30.67 (95%CI: 4.89-56.45) mg/dL; p = 0.02 for low-dose VDS; and MD: 27.33 (95%CI: 2.06-52.59) mg/dL; p = 0.03 for high-dose VDS). Pertaining heterogeneity was high (I2 = 86%; and I2 = 51%, respectively), and some included studies had significantly higher baseline TG in the intervention arm. The sensitivity analyses revealed robust results. CONCLUSION VDS seems not to affect blood lipids in adults with MetS.
2.
The Effects of Vitamin D Supplementation on Markers Related to Endothelial Function Among Patients with Metabolic Syndrome and Related Disorders: A Systematic Review and Meta-Analysis of Clinical Trials.
Tabrizi, R, Vakili, S, Lankarani, KB, Akbari, M, Jamilian, M, Mahdizadeh, Z, Mirhosseini, N, Asemi, Z
Hormone and metabolic research = Hormon- und Stoffwechselforschung = Hormones et metabolisme. 2018;(8):587-596
Abstract
This systematic review and meta-analysis of randomized controlled trials (RCTs) were conducted to summarize the effect of vitamin D supplementation on endothelial function among people with metabolic syndrome and related disorders. Cochrane library, Embase, PubMed, and Web of Science database were searched to identify related RCTs published up 20th May 2018. To check heterogeneity a Q-test and I2 statistics were used. Data were pooled by using the random-effect model and standardized mean difference (SMD) was considered as summary effect size. Twenty-two trials of 931 potential citations were found to be eligible for current meta-analysis. The pooled findings by using random effects model indicated that vitamin D supplementation to individuals with MetS and related disorders significantly increased flow-mediated dilatation (FMD) (SMD=1.10; 95% CI, 0.38, 1.81, p=0.003). However, it did not affect pulse-wave velocity (PWV) (SMD=0.04; 95% CI, -0.25, 0.33, p=0.80) and augmentation index (AI) (SMD=0.07; 95% CI, -0.25, 0.40; p=0.65). Overall, this meta-analysis demonstrated that vitamin D supplementation to patients with metabolic syndrome and related disorders resulted in an improvement in FMD, but did not influence PWV and AI.
3.
The Effects of Vitamin D Supplementation on Biomarkers of Inflammation and Oxidative Stress Among Women with Polycystic Ovary Syndrome: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.
Akbari, M, Ostadmohammadi, V, Lankarani, KB, Tabrizi, R, Kolahdooz, F, Heydari, ST, Kavari, SH, Mirhosseini, N, Mafi, A, Dastorani, M, et al
Hormone and metabolic research = Hormon- und Stoffwechselforschung = Hormones et metabolisme. 2018;(4):271-279
Abstract
The current systematic review and meta-analysis of randomized controlled trials (RCTs) was conducted to summarize the effect of vitamin D supplementation on biomarkers of inflammation and oxidative stress among women with polycystic ovary syndrome (PCOS). Cochrane library, Embase, PubMed, and Web of Science database were searched to identify related randomized-controlled articles (RCTs) published up to November 2017. Two researchers assessed study eligibility, extracted data, and evaluated risk of bias of included RCTs, independently. To check heterogeneity Q-test and I2 statistics were used. Data were pooled by using the random-effect model and standardized mean difference (SMD) was considered as summary effect size. Seven RCTs were included into our meta-analysis. The findings showed that vitamin D supplementation in women with PCOS significantly decreased high-sensitivity C-reactive protein (hs-CRP) (SMD -1.03; 95% CI, -1.58, -0.49; p <0.001) and malondialdehyde (MDA) (SMD -1.64, 95% CI -2.26 to -1.02, p <0.001), and significantly increased total antioxidant capacity (TAC) levels (SMD 0.86, 95% CI 0.08 to 1.64, p=0.03). Vitamin D supplementation had no significant effect on nitric oxide (NO) (SMD 0.11, 95% CI -0.44 to 0.66, p=0.69) and total glutathione (GSH) levels (SMD 0.54, 95% CI -0.20 to 1.28, p=0.15). Overall, the current meta-analysis demonstrated that vitamin D supplementation to women with PCOS resulted in an improvement in hs-CRP, MDA and TAC, but did not affect NO and GSH levels.