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Table 1 Study design and participant characteristics of trials included in meta-analysisa

From: The effect of grape products containing polyphenols on oxidative stress: a systematic review and meta-analysis of randomized clinical trials

Study.Year (Lu et al., 2018) [32] (Kanellos et al., 2017) [43] (Taghizadeh et al., 2016) [42] (Saldanha et al., 2016) [36] (Torres et al., 2015) [118] (Macedo et al., 2015) [45] (Zunino et al., 2014) [38] (Evans et al., 2014) [1] (Amoutzopoulos et al., 2013) [40] (Noguer et al., 2012) [117] (Pourghassem-Gargari et al., 2011) [44] (Mellen et al., 2010) [119] (Estruch et al., 2011) [115] (Lafay et al., 2009) [116] (Hollis et al., 2009) [37] (Rankin et al., 2008) [39] (Avellone et al., 2006) [114]
Product of Intervention group OPCs Raisin GSE Resveratrol Red wine Resveratrol Grape Powder WGE grape-based beverage (hardaliye) LPD + dealcoholized wine GSE GSE Red wine Grape extract Concord grape juice Raisin Red wine
Country Taiwan Greece Iran Brazil Spain Brazil USA Canada Turkey Spain Iran USA Spain France USA USA Italy
Study design Parallel Parallel Parallel Cross-over Cross-over Parallel Cross-over Cross-over Parallel Cross-over Parallel Cross-over Cross-over Cross-over Parallel Cross-over Cross-over
Sample Size (I/C) 13/14 22/14 20/20 9/11 16/16 30/30 24/24 13/12 39/17 8/8 26/22 50/50 20/20 20/20 25/26 17/17 24/24
Health status of participants COPD patient Healthy smokers Healthy subjects CKD patient Healthy subjects Healthy subjects Healthy obese prehypertensive, overweight Healthy subjects Healthy subjects T2D CAD or ≥ 1 cardiac risk factor Healthy subjects Healthy subjects Healthy subjects Over weight Healthy subjects
Age of participantsb, y (I/C) 71 ± 7.2
/ 71 ± 7.4
30.8 ± 7.5/29.8 ± 5.23 19.8 ± 5 /21.6 ± 7 63.0 ± 7.5/62.0 ± 8.4 Total: 25.5 21.46 ± 9.68 /22.3 ± 9.73 Men: 37.1 ± 10.5 Women: 34.7 ± 13.9 46.1 ± 11.1 /38.0 ± 12.3 37.44 ± 8.33 /34.18 ± 5.96 Total: 28 ± 5.3 Total: 47.5 Total: 52.1 ± 8.1 Total: 37.6 ± 7.4 Total: 21.6 ± 8.9 22.0 ± 4.0/26.0 ± 9.0 Total: 26.5 ± 7.6 Total: 43 ± 10.6
BMI of participantsb, Kg/m2 (I/C) NR 24.4 ± 2.81/24.4 ± 2.99 21.6 ± 3.6/21.2 ± 1.5 26.8 ± 5.6/28.6 ± 4.4 NR NR Men: 36.6 ± 4.4 Women: 36.9 ± 5.3 Total:29.95 24.81 ± 3.29/24.97 ± 3.04 NR 31.0 ± 6.0/30.0 ± 4.0 Total: 29.8 ± 6.0 NR Total: 23.9 ± 2.4 27.0 ± 1.6 /27.0 ± 1.5 Total: 33.5 ± 6.7 Total: 23 ± 2.5
Sex of participants M NR 27 0 9 8 60 8 12 34 NR NR 25 40 20 NR 8 28
F NR 9 40 11 8 0 16 14 22 NR NR 25 0 0 NR 9 20
Product of Control group Placebo No raisin Placebo Placebo Water with sugar Placebo Placeb Powder Placebo No hardaliye LPD Placebo Placebo Gin Placebo Polyphenol free grape flavored drink Placebo Usual wine
Dose of grape product, g/d 0.15 90 0.6 0.5 160 0.1 92 0.35 500 300 0.2 1.3 320 0.4 480 90 250
Dose of GPP, mg/d ~ 150 178.75 ~ 600 ~ 500 361.6 ~ 100 62.24 ~ 350 1066 ~ 780 ~ 200 ~ 1300 ~ 832 ~ 400 ~ 945.5 ~ 178.75 ~ 650
Period, wk 8 4 8 16 8 12 9 6 6 2 8 14 12 10 12 8 12
SODb, U/mgHb I 0.0061 ± 0.003 NR NR 0.0037 ± 0.002 NR 0.005 ± 0.002 NR 0.004 ± 0.0007 NR 0.04 ± 0.01 0.001 ± 0.0002 NR 0.001 ± 0.0002 0.0025 ± 0.0004 NR NR NR
C 0.0068 ± 0.003 NR NR 0.0039 ± 0.002 NR 0.006 ± 0.003 NR 0.005 ± 0.002 NR 0.05 ± 0.01 0.001 ± 0.0001 NR 0.001 ± 0.0001 0.0023 ± 0.0003 NR NR NR
TACb, mmol/L I NR NR 811.4 ± 122.9 NR 19.3 ± 2.4 NR NR 1.7 ± 1.14 0.23 ± 0.07 NR NR 0.6 ± 0.07 NR NR NR NR 0.9 ± 0.02
C NR NR 826.5 ± 128.9 NR 17.7 ± 1.5 NR NR 1.2 ± 0.8 0.25 ± 0.1 NR NR 0.6 ± 0.07 NR NR NR NR 1 ± 0.02
ORACb, μmol/L I NR NR NR NR NR NR 1536.14 ± 164.44 NR NR 2586 ± 473 NR NR NR 13,885 ± 1609.2 2093 ± 827 7163 ± 1513 NR
C NR NR NR NR NR NR 1536.14 ± 164.44 NR NR 2657 ± 406 NR NR NR 14,488 ± 1698.6 2555 ± 936 8335.7 ± 1760.6 NR
MDAb, μmol/L I 7.1 ± 1.3 4.3 ± 1.4 4.7 ± 2.1 NR NR NR NR NR 1.5 ± 0.3 NR 3.5 ± 0.6 0.5 ± 0.2 0.041 ± 0.012 NR NR NR NR
C 7.9 ± 1.5 5.1 ± 2.2 3.9 ± 1.1 NR NR NR NR NR 1.6 ± 0.4 NR 3.5 ± 0.7 0.5 ± 0.2 0.049 ± 0.017 NR NR NR NR
GPXb, U/mgHb I NR NR NR 0.0008 ± 0.0003 NR 0.097 ± 0.037 NR NR NR NR 0.029 ± 0.003 NR 0.0023 ± 0.0005 0.018 ± 0.004 NR NR NR
C NR NR NR 0.0007 ± 0.0003 NR 0.123 ± 0.036 NR NR NR NR 0.022 ± 0.002 NR 0.0022 ± 0.0006 0.017 ± 0.004 NR NR NR
  1. a Meta-analyses were conducted with the use of the random-effects model. Main analysis: all studies from Table 1, includes both no-grape polyphenols controls and grape product contain polyphenols intake. BMI Body Mass Index, C Control group, CAD Coronary artery disease, CKD Chronic Kidney Disease, COPD Chronic Obstructive Pulmonary Disease, F Female, GPP Grape polyphenols, GPX Glutathione Peroxidase, GSE Grape Seed Extract, I Intervention group, LPD Low phenolic diet, M Male, MDA malondialdehyde, NR Not Reported, OPCs Oligomeric proanthocyanidins extracted from grape seeds, ORAC Oxygen Radical Absorbance Capacity, SOD Superoxide Dismutase, TAC Total Antioxidant Capacity, T2D Type 2 diabetes, USA United States of America, WGP Whole grape extract
  2. b Values are mean ± SDs