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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