scholarly journals Dietary Antioxidants, Circulating Antioxidant Concentrations, Total Antioxidant Capacity, and Risk of All-Cause Mortality: A Systematic Review and Dose-Response Meta-Analysis of Prospective Observational Studies

2018 ◽  
Vol 9 (6) ◽  
pp. 701-716 ◽  
Author(s):  
Ahmad Jayedi ◽  
Ali Rashidy-Pour ◽  
Mohammad Parohan ◽  
Mahdieh Sadat Zargar ◽  
Sakineh Shab-Bidar
Keyword(s):  
Systematic Review ◽  
Antioxidant Capacity ◽  
Dose Response ◽  
Total Antioxidant Capacity ◽  
Observational Studies ◽  
Meta Analysis ◽  
Dietary Antioxidants ◽  
All Cause Mortality ◽  
Total Antioxidant

Higher dietary total antioxidant capacity (TAC) reduces the risk of cardio-metabolic risk factors among adults: An updated systematic review and meta-analysis

2021 ◽  
pp. 1-15
Author(s):  
Mahdieh Abbasalizad Farhangi ◽  
Ali Mohammad-Rezaei
Keyword(s):  
Systematic Review ◽  
Blood Pressure ◽  
Antioxidant Capacity ◽  
Total Antioxidant Capacity ◽  
Observational Studies ◽  
Meta Analysis ◽  
Dietary Antioxidants ◽  
Total Antioxidant ◽  
Dietary Total Antioxidant Capacity

Abstract. Background: Numerous studies have revealed the protective role of dietary antioxidants against hypertension and diabetes. In the current systematic review and meta-analysis, we evaluated the possible role of dietary total antioxidant capacity (TAC) against metabolic parameters in the adult population. Methods: A literature search of authentic electronic resources including PubMed, Scopus, Web of Sciences, and Cochrane had been performed to retrieve the qualified observational studies that reported the mean plus/minus the SD for the parameter in subjects of the highest versus lowest dietary TAC categories up to July 2020. Results: Totally, the number of included studies was 13 for fasting blood sugar (FBS), 12 for systolic blood pressure (SBP), and 12 for diastolic blood pressure (DBP), with the participants’ number of 26349. The results of the current study showed that being at highest category of TAC significantly reduces serum FBS (WMD: −2.381; CI: −3.445, −1.316; P<0.001), SBP (WMD: −1.080; CI: −1.458, −0.701; P<0.001) and DBP (WMD: −0.854; CI: −1.655, −0.052; P<0.001), while no significant difference in the serum insulin, HOMA-IR values, prevalence of type 2 diabetes (T2DM) (P=0.37) and hypertension (HTN) (P=0.09) was observed. Subgroup analysis revealed the geographical location, dietary assessment tool, sample size, and gender as possible sources of heterogeneity. Conclusion: Higher intake of dietary TAC was associated with reduced SBP, DBP, and FBS in the current observational studies of this meta-analysis. These findings further confirm the clinical importance of dietary antioxidants in the prevention of different metabolic disorders.

Effects of Astaxanthin Supplementation on Oxidative Stress

2020 ◽  
Vol 90 (1-2) ◽  
pp. 179-194 ◽  
Author(s):  
Di Wu ◽  
Hao Xu ◽  
Jinyao Chen ◽  
Lishi Zhang
Keyword(s):  
Systematic Review ◽  
Superoxide Dismutase ◽  
Antioxidant Capacity ◽  
Subgroup Analysis ◽  
Total Antioxidant Capacity ◽  
Meta Analysis ◽  
Antioxidant Effect ◽  
High Dose ◽  
Standard Mean Difference ◽  
Total Antioxidant

Abstract. A systematic review and meta-analysis was conducted in six databases from 1948 to 2015 to assess the antioxidant activity of astaxanthin in humans. Nine randomized controlled trials were included in the systematic review. Results of meta-analysis revealed a borderline significant antioxidant effect of astaxanthin between the intervention and control groups, with a malondialdehyde-lowering effect for lipid peroxidation ( p = 0.050). However, the data included here are insufficient. When compared with the baseline in intervention groups, the meta-analysis suggested that astaxanthin supplements significantly decreased plasma malondialdehyde {Standard mean difference (SMD) −1.32 μmol/L [95% CI −1.92, −0.72]; p < 0.0001} and isoprostane (SMD −3.10 ng/mL [95% CI −4.69, −1.51]; p < 0.0001). However, they increased superoxide dismutase (SMD 1.57 U/mL [95% CI 0.57, 2.56]; p = 0.002) and total antioxidant capacity (SMD 0.77 mmol 95% CI [0.12, 1.43]; p = 0.018). For dosage subgroup analysis, high dose (≥20 mg/day) of astaxanthin showed significant antioxidant effect (on total antioxidant capacity, isoprostane, and superoxide dismutase, p < 0.05). However, low dose (<20 mg/day) showed no significant effect ( p > 0.05). Further duration subgroup analysis indicated that astaxanthin showed antioxidant effect after a 3-week intervention ( p < 0.001), whereas this effect was not observed after a 12-week or 3-month intervention (on isoprostane and superoxide dismutase, p > 0.05). This review suggested that the antioxidant effect of astaxanthin on humans is unclear.

scholarly journals Incidence, risk factors and prognostic effect of imaging right ventricular involvement in patients with COVID-19: a dose–response analysis protocol for systematic review

BMJ Open ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. e049866
Author(s):  
Chenghui Zhou ◽  
Baohui Lou ◽  
Hui Li ◽  
Xin Wang ◽  
Hushan Ao ◽  
...  
Keyword(s):  
Risk Factors ◽  
Systematic Review ◽  
Right Ventricular ◽  
Dose Response ◽  
Meta Analysis ◽  
Adult Patients ◽  
Sensitivity Analyses ◽  
Prognostic Effect ◽  
All Cause Mortality ◽  
Incidence Risk

IntroductionEmerging evidence has shown that COVID-19 infection may result in right ventricular (RV) disturbance and be associated with adverse clinical outcomes. The aim of this meta-analysis is to summarise the incidence, risk factors and the prognostic effect of imaging RV involvement in adult patients with COVID-19.MethodsA systematical search will be performed in PubMed, EMBase, ISI Knowledge via Web of Science and preprint databases (MedRxiv and BioRxiv) (until October 2021) to identify all cohort studies in adult patients with COVID-19. The primary outcome will be the incidence of RV involvement (dysfunction and/or dilation) assessed by echocardiography, CT or MRI. Secondary outcomes will include the risk factors for RV involvement and their association with all-cause mortality during hospitalisation. Additional outcomes will include the RV global or free wall longitudinal strain (RV-GLS or RV-FWLS), tricuspid annular plane systolic excursion (TAPSE), fractional area change (FAC) and RV diameter. Univariable or multivariable meta-regression and subgroup analyses will be performed for the study design and patient characteristics (especially acute or chronic pulmonary embolism and pulmonary hypertension). Sensitivity analyses will be used to assess the robustness of our results by removing each included study at one time to obtain and evaluate the remaining overall estimates of RV involvement incidence and related risk factors, association with all-cause mortality, and other RV parameters (RV-GLS or RV-FWLS, TAPSE, S’, FAC and RV diameter). Both linear and cubic spline regression models will be used to explore the dose–response relationship between different categories (>2) of RV involvement and the risk of mortality (OR or HR).Ethics and disseminationThere was no need for ethics approval for the systematic review protocol according to the Institutional Review Board/Independent Ethics Committee of Fuwai Hospital. This meta-analysis will be disseminated through a peer-reviewed journal for publication.PROSPERO registration numberCRD42021231689.

scholarly journals Dietary and circulating vitamin C, vitamin E, β-carotene and risk of total cardiovascular mortality: a systematic review and dose–response meta-analysis of prospective observational studies

2019 ◽  
Vol 22 (10) ◽  
pp. 1872-1887 ◽  
Author(s):  
Ahmad Jayedi ◽  
Ali Rashidy-Pour ◽  
Mohammad Parohan ◽  
Mahdieh Sadat Zargar ◽  
Sakineh Shab-Bidar
Keyword(s):  
Systematic Review ◽  
Vitamin E ◽  
Vitamin C ◽  
Dose Response ◽  
Observational Studies ◽  
Meta Analysis ◽  
Dietary Intakes ◽  
Relative Risks ◽  
Β Carotene ◽  
Cvd Mortality

AbstractObjectiveThe present review aimed to quantify the association of dietary intake and circulating concentration of major dietary antioxidants with risk of total CVD mortality.DesignSystematic review and meta-analysis.SettingSystematic search in PubMed and Scopus, up to October 2017.ParticipantsProspective observational studies reporting risk estimates of CVD mortality across three or more categories of dietary intakes and/or circulating concentrations of vitamin C, vitamin E and β-carotene were included. A random-effects meta-analysis was conducted.ResultsA total of fifteen prospective cohort studies and three prospective evaluations within interventional studies (320 548 participants and 16 974 cases) were analysed. The relative risks of CVD mortality for the highest v. the lowest category of antioxidant intakes were as follows: vitamin C, 0·79 (95 % CI 0·68, 0·89; I2=46 %, n 10); vitamin E, 0·91 (95 % CI 0·79, 1·03; I2=51 %, n 8); β-carotene, 0·89 (95 % CI 0·73, 1·05; I2=34 %, n 4). The relative risks for circulating concentrations were: vitamin C, 0·60 (95 % CI 0·42, 0·78; I2=65 %, n 6); α-tocopherol, 0·82 (95 % CI 0·76, 0·88; I2=0 %, n 5); β-carotene, 0·68 (95 % CI 0·52, 0·83; I2=50 %, n 6). Dose–response meta-analyses demonstrated that the circulating biomarkers of antioxidants were more strongly associated with risk of CVD mortality than dietary intakes.ConclusionsThe present meta-analysis demonstrates that higher vitamin C intake and higher circulating concentrations of vitamin C, vitamin E and β-carotene are associated with a lower risk of CVD mortality.

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