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1.
The Acute Effects of Prolonged Uninterrupted Sitting on Vascular Function: A Systematic Review and Meta-analysis.
Taylor, FC, Pinto, AJ, Maniar, N, Dunstan, DW, Green, DJ
Medicine and science in sports and exercise. 2022;(1):67-76
Abstract
OBJECTIVE This study aimed to determine the dose-response relationship between prolonged sitting and vascular function in healthy individuals and those with metabolic disturbances and to investigate the acute effects, on vascular function, of interventions that target interrupting prolonged sitting. DESIGN This is a systematic review with meta-analysis. DATA SOURCES Ovid Embase, Ovid Medline, PubMed, and CINAHL were searched from inception to 4 December 2020. ELIGIBILITY CRITERIA Randomized crossover trials, quasi-randomized trials, and parallel group trials where vascular function (flow-mediated dilation [FMD]) was assessed before and after an acute period of sedentary behavior was used in this study. RESULTS Prolonged sitting resulted in a significant decrease in the standardized mean change (SMC) for lower-limb FMD at the 120-min (SMC = -0.85, 95% confidence interval [CI] = -1.32 to -0.38) and 180-min (SMC = -1.18, 95% CI = -1.69 to -0.66) time points. A similar pattern was observed for lower-limb shear rate. No significant changes were observed for any outcomes in the upper limb. Subgroup analysis indicated that prolonged sitting decreased lower-limb FMD in healthy adults (SMC = -1.33, 95% CI = -1.89 to -0.78) who had higher a priori vascular endothelial function, but not in those with metabolic and vascular dysfunction (SMC = -0.51, 95% CI = -1.18 to 0.15). Interrupting sitting with active interruptions increased the standardized mean difference for FMD, relative to prolonged sitting, but it was not statistically significant (0.13, 95% CI = -0.20 to 0.45). CONCLUSIONS Lower-limb vascular function is progressively impaired as a consequence of prolonged sitting, up to 180 min. A similar trend was not observed in upper-limb vascular function. Subgroup analysis indicated that prolonged sitting negatively affects healthy populations, a finding not observed in those with metabolic disturbances. Regularly interrupting sitting with activity may be beneficial for those with metabolic disturbances.
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2.
Effects of tree nut and groundnut consumption compared with those of l-arginine supplementation on fasting and postprandial flow-mediated vasodilation: Meta-analysis of human randomized controlled trials.
Smeets, ETHC, Mensink, RP, Joris, PJ
Clinical nutrition (Edinburgh, Scotland). 2021;(4):1699-1710
Abstract
INTRODUCTION l-arginine supplementation may improve vascular endothelial function. As tree nuts and groundnuts are a source of the amino acid l-arginine, we performed a meta-analysis of human randomized controlled trials (RCTs) to compare effects of tree nut and groundnut consumption with those of l-arginine supplementation on fasting and postprandial endothelial function as assessed by flow-mediated vasodilation of the brachial artery (FMD). METHODS Summary estimates of weighted mean differences (WMDs) in FMD and 95% confidence intervals (CIs) were calculated using random-effect meta-analyses. RESULTS A total of thirteen RCTs focusing on tree nut and groundnut consumption and nineteen RCTs investigating effects of l-arginine supplementation were included. Longer-term consumption of tree nuts and groundnuts increased fasting FMD by 1.09 %-point (PP) (95% CI: 0.49, 1.69, P < 0.001; I2: 76.7%, P < 0.001), while l-arginine supplementation (daily range: 3-21 g) increased fasting FMD by 0.53 PP (95% CI: 0.12, 0.93; P = 0.012; I2: 91.6%, P < 0.001). Effects between treatments were not statistically different (P = 0.31). Tree nut and groundnut consumption did not affect postprandial FMD responses (1.25 PP, 95% CI: -0.31, 2.81, P = 0.12; I2: 91.4%, P < 0.001), whereas l-arginine supplementation (range: 3-15 g) improved FMD during the postprandial phase by 2.02 PP (95% CI: 0.92, 3.13, P < 0.001; I2: 99.1%, P < 0.001). However, treatment effects did not differ significantly (P = 0.60). Overall, these results derive from high-quality evidence. CONCLUSION Longer-term consumption of tree nuts and groundnuts, as well as l-arginine supplementation did improve fasting endothelial function, as assessed by FMD. However, the positive effects of tree nuts and groundnuts could not be fully explained by the amount of l-arginine in these nuts. Only l-arginine supplementation did improve postprandial FMD, but effects were not different from those of tree nuts and groundnuts. Future studies should focus on the identifications of the bioactive nutrients in tree nuts and groundnuts and mechanistic pathways behind differences in postprandial and longer-term fasting changes in FMD.
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3.
Effects of Oral Magnesium Supplementation on Vascular Function: A Systematic Review and Meta-analysis of Randomized Controlled Trials.
Marques, BCAA, Klein, MRST, da Cunha, MR, de Souza Mattos, S, de Paula Nogueira, L, de Paula, T, Corrêa, FM, Oigman, W, Neves, MF
High blood pressure & cardiovascular prevention : the official journal of the Italian Society of Hypertension. 2020;(1):19-28
Abstract
INTRODUCTION The effects of magnesium (Mg) supplementation on vascular function have been evaluated in some randomized controlled trials (RCT) but their results are conflicting. AIM: A systematic review and meta-analysis were conducted to summarize the effects of oral Mg supplementation on vascular function in RCT. METHODS The databases MEDLINE (PubMed), Embase, Web of Science and Cochrane Library were accessed from inception to May 27, 2019. Intergroup differences (treatment vs. control group) related to changes in flow-mediated dilation (FMD) and pulse wave velocity (PWV), expressed as mean and standard deviation, were used to evaluate the effect of Mg supplementation on these outcomes. The results of the meta-analysis were expressed using a random-effects model. The heterogeneity between studies was evaluated using the I2 statistic. RESULTS The oral supplementation of Mg had no significant effect on FMD (mean difference 2.13; 95% CI - 0.56, 4.82; p = 0.12) and PWV (mean difference - 0.54, 95% CI - 1.45, 0.36, p = 0.24). Heterogeneity for both outcomes (FMD and PWV) was high (I2 = 99%, p < 0.001). However, in subgroup analyses, oral Mg significantly improved FMD in studies longer than 6 months, in unhealthy subjects, in individuals older than 50 years, or in those with body mass index (BMI) ≥ 25 kg/m2. The reduced number of RCT and the heterogeneity among them were the main limitations. CONCLUSIONS This meta-analysis suggest that oral Mg supplementation may improve endothelial function when conducted at least for 6 months and in unhealthy, overweight or older individuals. Registration number: PROSPERO CRD42019111462.
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4.
Effect of vitamin D supplementation on endothelial function - An updated systematic review with meta-analysis and meta-regression.
Pincombe, NL, Pearson, MJ, Smart, NA, King, N, Dieberg, G
Nutrition, metabolism, and cardiovascular diseases : NMCD. 2019;(12):1261-1272
Abstract
BACKGROUND AND AIMS Atherogenesis and endothelial dysfunction contribute to cardiovascular risk and vitamin D has been implemented in endothelial repair. This systematic review, meta-analysis and meta-regression aims to establish the effect of vitamin D supplementation on endothelial function. METHODS AND RESULTS To conduct the systematic review we searched the Cochrane Library of Controlled Trials, PubMed, ProQuest and EMBASE for randomized controlled trials that investigated the effects of vitamin D supplementation on flow-mediated dilation (FMD%), pulse wave velocity (PWV), and central augmentation index (AIx). Meta-analysis was based on a random effects model and inverse-variance methods to calculate either mean difference (MD) or standardized mean difference (SMD) as effects sizes. This was followed by meta-regression investigating the effect of baseline vitamin D concentrations, vitamin D dosing and study duration. Risk of bias was assessed using the JADAD scale and funnel plots. We identified 1056 studies of which 26 studies met inclusion criteria for quantitative analysis. Forty-two percent of the 2808 participants had either deficient or insufficient levels of vitamin D. FMD% (MD 1.17% (95% CI -0.20, 2.54), p = 0.095), PWV (SMD -0.09 m/s (95% CI -0.24, 0.07), p = 0.275) and AIx (SMD 0.05% (95% CI -0.1, 0.19), p = 0.52) showed no improvement with vitamin D supplementation. Sub-analysis and meta-regression revealed a tendency for AIx and FMD% to increase as weekly vitamin doses increased; no other significant relationships were identified. CONCLUSIONS Vitamin D supplementation showed no improvement in endothelial function. More evidence is required before recommendations for management of endothelial dysfunction can be made.
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5.
The Effects of Resveratrol Supplementation on Endothelial Function and Blood Pressures Among Patients with Metabolic Syndrome and Related Disorders: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.
Akbari, M, Tamtaji, OR, Lankarani, KB, Tabrizi, R, Dadgostar, E, Kolahdooz, F, Jamilian, M, Mirzaei, H, Asemi, Z
High blood pressure & cardiovascular prevention : the official journal of the Italian Society of Hypertension. 2019;(4):305-319
Abstract
INTRODUCTION There are current trials investigating the effect of resveratrol supplementation on endothelial function and blood pressures among patients with metabolic syndrome (MetS); however, the findings are controversial. AIM: This systematic review and meta-analysis of randomized controlled trials (RCTs) were carried out to summarize the effects of resveratrol supplementation on endothelial activation and blood pressures among patients with MetS and related disorders. METHODS We searched systematically online databases including: PubMed-Medline, Embase, ISI Web of Science and Cochrane Central Register of Controlled Trials until October, 2018. Two independent authors extracted data and assessed the quality of included articles. Data were pooled using the fixed- or random-effects model and considered as standardized mean difference (SMD) with 95% confidence intervals (95% CI). RESULTS Out of 831 electronic citations, 28 RCTs (with 33 findings reported) were included in the meta-analyses. The findings showed that resveratrol intervention significantly increased flow-mediated dilatation (FMD) levels (SMD 1.77; 95% CI 0.25, 3.29; P = 0.02; I2: 96.5). However, resveratrol supplements did not affect systolic blood pressure (SBP) (SMD - 0.27; 95% CI - 0.57, 0.03; P = 0.07; I2: 88.9) and diastolic blood pressure (DBP) (SMD - 0.21; 95% CI - 0.52, 0.11; P = 0.19; I2: 89.8). CONCLUSIONS Resveratrol supplementation significantly increased FMD among patients with MetS and related disorders, but did not affect SBP and DBP. Additional prospective studies are needed to investigate the effect of resveratrol supplementation on endothelial function and blood pressures, using higher-dose of resveratrol with longer durations.
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6.
Eating and arterial endothelial function: a meta-analysis of the acute effects of meal consumption on flow-mediated dilation.
Thom, NJ, Early, AR, Hunt, BE, Harris, RA, Herring, MP
Obesity reviews : an official journal of the International Association for the Study of Obesity. 2016;(11):1080-1090
Abstract
Given that endothelial dysfunction precedes atherosclerotic cardiovascular disease, exploring the parameters that modify postprandial flow-mediated dilation (FMD) is important for public health. The objectives of the study are to estimate the population effect of meal ingestion on FMD and to determine how the effect varied based on patient characteristics and modifiable methodological features. Articles published before June 2015 were located using MEDLINE, PubMed and Web of Science. One hundred fifty-four effects were derived from 78 articles involving 2,548 subjects were selected. Included articles required measurement of FMD in adults before and after meal ingestion. Effects were analysed using an unstandardized mean gain random effects model, and significant moderators were analysed using meta-regression. Meal consumption significantly reduced FMD by a heterogeneous mean effect size delta (Δ) of -2.03 (95% CI: [-2.28, -1.77]), an ~2% reduction in FMD. FMD reductions were larger among normal weight individuals, males, those with a cardio-metabolic disorder, those with elevated baseline FMD, and individuals with impaired glucose tolerance at baseline. Macronutrient meal ingestion significantly reduced FMD, an effect that was moderated by body mass index, sex and two-way interactions between disease status and both baseline FMD and baseline blood glucose levels.
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7.
Influence of beta-blockers on endothelial function: A meta-analysis of randomized controlled trials.
Peller, M, Ozierański, K, Balsam, P, Grabowski, M, Filipiak, KJ, Opolski, G
Cardiology journal. 2015;(6):708-16
Abstract
BACKGROUND Endothelial dysfunction (ED) frequently precedes cardiovascular diseases (CVD) and is a well-established risk factor of major adverse cardiac events. Beta-blockers are the fundamental drugs used in CVD treatment. METHODS A systematic literature search for randomized controlled trials investigating influence of beta-blockers on endothelial function assessed by flow-mediated dilation (FMD) was performed in the PubMed and Cochrane Databases. RESULTS Sixteen full-text studies involving a total of 1,273 patients were included in the final analysis. The mean age of participating patients ranged from 44.9 to 63.2 years, the follow-up duration from 1 to 12 months. The comparison of FMD change between the beta-blockers and placebo groups showed a statistically significant effect of beta-blockers on endothelial function (mean difference [MD] 0.83; 95% confidence interval [CI] 0.11-1.55; p = 0.02). Third generation beta-blockers improved FMD in a statistically significant manner compared with second generation beta-blockers (MD 1.65; 95% CI 0.17-3.11; p = 0.03). Beta-blockers gave an FMD change similar to that obtained with angiotensin receptor blockers (ARB), calcium channel blockers (CCB) or hydrochlorothiazide. The FMD value in the beta-blocker group was significantly lower compared with the group treated with angiotensin converting enzyme inhibitors (ACEI) (MD -0.79; 95% CI -1.37-(-0.21); p = 0.008) and higher than in the ivabradine group (1.6 ± 3.61 vs -0.3 ± 1.66; p = 0.02). CONCLUSIONS Beta-blockers improve the endothelial function compared with placebo. More-over, third generation beta-blockers improve FMD values significantly better than the second generation ones. Beta-blockers had similar effect on endothelial function as did ARB, CCB or diuretics. However, the beneficial effect of beta-blockers was lower when confronted with ACEI.
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8.
Exercise and Vascular Function in Child Obesity: A Meta-Analysis.
Dias, KA, Green, DJ, Ingul, CB, Pavey, TG, Coombes, JS
Pediatrics. 2015;(3):e648-59
Abstract
CONTEXT Conduit artery flow-mediated dilation (FMD) is a noninvasive index of preclinical atherosclerosis in humans. Exercise interventions can improve FMD in both healthy and clinical populations. OBJECTIVE This systematic review and meta-analysis aimed to summarize the effect of exercise training on FMD in overweight and obese children and adolescents as well as investigate the role of cardiorespiratory fitness (peak oxygen consumption [Vo2peak]) on effects observed. DATA SOURCES PubMed, Medline, Embase, and Cinahl databases were searched from the earliest available date to February 2015. STUDY SELECTION Studies of children and/or adolescents who were overweight or obese were included. DATA EXTRACTION Standardized data extraction forms were used for patient and intervention characteristics, control/comparator groups, and key outcomes. Procedural quality of the studies was assessed using a modified version of the Physiotherapy Evidence Base Database scale. RESULTS A meta-analysis involving 219 participants compared the mean difference of pre- versus postintervention vascular function (FMD) and Vo2peak between an exercise training intervention and a control condition. There was a significantly greater improvement in FMD (mean difference 1.54%, P < .05) and Vo2peak (mean difference 3.64 mL/kg/min, P < .05) after exercise training compared with controls. LIMITATIONS Given the diversity of exercise prescriptions, participant characteristics, and FMD measurement protocols, varying FMD effect size was noted between trials. CONCLUSIONS Exercise training improves vascular function in overweight and obese children, as indicated by enhanced FMD. Further research is required to establish the optimum exercise program for maintenance of healthy vascular function in this at-risk pediatric population.
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9.
Weight loss improves fasting flow-mediated vasodilation in adults: a meta-analysis of intervention studies.
Joris, PJ, Zeegers, MP, Mensink, RP
Atherosclerosis. 2015;(1):21-30
Abstract
BACKGROUND Obesity is associated with vascular endothelial dysfunction. Effects of weight loss on endothelial function are however not clear. Therefore, we performed a meta-analysis to quantify effects of weight loss on flow-mediated vasodilation (FMD) of the brachial artery, a measurement of endothelial function. METHODS Studies with experimental (RCTs) and quasi-experimental designs published before June 2014 were identified by a systematic search. Changes in FMD were defined as the difference between measurements before and after the study. For RCTs, changes were corrected for those in the no-weight loss control group. Summary estimates of weighted mean differences (WMDs) in FMD and 95% confidence intervals (CIs) were calculated using random-effect meta-analyses. The impact of subject characteristics, type of weight-loss treatment, and dietary composition on changes in FMD was also investigated. RESULTS Four RCTs involving 265 subjects were included. Weight loss increased FMD vs. control by 3.29% (95% CI: 0.98-5.59%; P = 0.005; mean weight loss: 8.6 kg). A total of 1517 subjects participated in 33 studies with 49 relevant study arms. It was estimated that each 10 kg decrease in body weight increased fasting FMD by 1.11% (95% CI: 0.47-1.76%; P = 0.001). Effects were more pronounced when participants had coexisting obesity-related morbidities. Also, effects may be larger when subjects received low-fat diets or weight-reduction regimens including exercise therapy or weight-loss medication. CONCLUSION Weight loss significantly improves fasting FMD in adults, which is a risk marker for cardiovascular disease. Effects may depend on subject characteristics, type of weight-loss treatment, and dietary composition.
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10.
Microvascular Dilator Function in Athletes: A Systematic Review and Meta-analysis.
Montero, D, Walther, G, Diaz-Cañestro, C, Pyke, KE, Padilla, J
Medicine and science in sports and exercise. 2015;(7):1485-94
Abstract
PURPOSE Despite the growing research interest in vascular adaptations to exercise training over the last few decades, it remains unclear whether microvascular function in healthy subjects can be further improved by regular training. Herein, we sought to systematically review the literature and determine whether microvascular dilator function is greater in athletes compared to age-matched healthy untrained subjects. METHODS We conducted a systematic search of MEDLINE, Cochrane, EMBASE, and Web of Science since their inceptions until October 2013 for articles evaluating indices of primarily microvascular endothelium-dependent or endothelium-independent dilation (MVEDD and MVEID, respectively) in athletes. A meta-analysis was performed to determine the standardized mean difference (SMD) in MVEDD and MVEID between athletes and age-matched controls. Subgroup analyses were used to study potential moderating factors. RESULTS Thirty-six studies were selected after systematic review, comprising 521 athletes (506 endurance-trained and 15 endurance- and strength-trained) and 496 age-matched control subjects. After data pooling, athletes presented higher MVEDD (31 studies; SMD, 0.47; P < 0.00001) and MVEID (14 studies; SMD, 0.51; P < 0.00001) compared with the control subjects. Similar results were observed in young (younger than 40 yr) and master (older than 55 yr) athletes when analyzed separately. CONCLUSION Both young and master athletes present enhanced microvascular function compared with age-matched untrained but otherwise healthy subjects. These data provide evidence of a positive association between exercise training and microvascular function in the absence of known underlying cardiovascular disease.