Table 3 Subgroup analysis to assess the effect of grape polyphenols supplementation on different biomarkers of oxidative stress levels^a

  Unhealthy

4

< 0.001

(−0.001, 0.001)

0.99

  Healthy

4

0.450

(0.23, 0.66)^b

< 0.001

 10 wk. or more

4

0.085

(−0.01, 0.18)^b

0.09

 lower than 10 wk

4

0.001

(−0.006, 0.007)

0.86

 400 mg/d or more

4

0.539

(0.24, 0.82)^b

< 0.001

 Lower than 400 mg/d

4

< 0.001

(−0.001, 0.001)

0.75

 Cross-over

4

0.539

(0.24, 0.82)^b

< 0.001

 Parallel

4

< 0.001

(−0.001, 0.001)

0.75

 Good

4

0.085

(−0.01, 0.18)

0.08

 Fair

3

< -0.001

(−0.001, 0.001)

0.75

 Weak

1

2.399

(2.01, 2.78)^b

<  0.001

  Unhealthy

2

−0.254

(−0.65, 0.14)

0.21

  Healthy

4

2.829

(0.13, 5.52)^b

0.04

 More than 6 wk

3

3.814

(−4.14, 11.77)

0.34

 6 wk. or lower

3

0.084

(−0.36, 0.52)

0.71

 More than 650 mg/d

2

−0.058

(−0.22, 0.11)

0.49

 650 mg/d or lower

4

2.595

(−2.53, 7.72)

0.32

 Cross-over

3

2.785

(0.01, 5.55)^b

0.04

 Parallel

3

−0.164

(−0.65, 0.33)

0.51

 Good

3

−0.145

(−1.18, −0.10)^c

<  0.001

 Fair

2

0.266

(−0.22, 0.75)

0.28

 Weak

1

8.01

(7.54, 8.49)^b

<  0.001

 Abnormal wt.^d

2

−0.030

(−0.46, 0.40)

0.89

 Healthy

3

0.524

(0.42, 0.62)^b

<  0.001

 10 wk. or more

2

0.543

(0.43, 0.64)^b

<  0.001

 Lower than 10 wk

3

0.089

(−0.26, 0.44)

0.62

More than 400 mg/d 

2

0.377

(0.08, 0.67)^b

0.01

 400 mg/d or lower

3

0.161

(−0.26, 0.58)

0.46

 Cross-over

4

0.210

(−0.15, 0.57)

0.25

 Parallel

1

−140.0

(−651.9, 371.9)

0.59

 Good

2

0.365

(0.01, 0.71)^b

0.03

 Fair

2

− 0.251

(−0.36, −0.13)^c

<  0.001

 Weak

1

0.377

(0.08, 0.67)^b

0.01

Unhealthy 

3

− 0.092

(−0.50, 0.32)

0.66

Healthy  

4

−0.214

(−0.62, 0.19)

0.30

8 wk. or more 

5

−0.149

(−0.47, 0.17)

0.36

Lower than 8 wk. 

2

0.096

(−1.14, 1.33)

0.88

600 mg/d or more 

4

−0.237

(−0.58, 0.11)

0.18

Lower than 600 mg/d 

3

−0.034

(−0.88, 0.81)

0.93

Cross-over 

2

0.003

(−0.05, 0.05)

0.90

Parallel 

5

−0.328

(−0.79, 0.14)

0.17

 Good

4

−0.072

(−0.55, 0.40)

0.77

 Fair

3

−0.313

(−0.67, 0.05)

0.09

  Unhealthy

2

0.009

(−0.02, 0.04)

0.60

  Healthy

3

0.044

(−0.03, 0.12)

0.30

 More than 10 wk

3

−0.002

(−0.01, 0.01)

0.83

 10 wk. or lower

2

0.068

(−0.07, 0.20)

0.33

 400 mg/d or more

3

0.063

(−0.02, 0.15)

0.16

 Lower than 400 mg/d

2

< 0.001

(−0.001, 0.001)

0.80

 Cross-over

3

0.063

(−0.02, 0.15)

0.16

 Parallel

2

< 0.001

(−0.001, 0.001)

0.80

 Good

3

0.063

(−0.02, 0.15)

0.16

 Fair

2

< 0.001

(−0.001, 0.001)

0.80