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Table 2 Subgroup analyses of odds ratios for the association between fiber intake and risk of prostate cancer

From: No association between fiber intake and prostate cancer risk: a meta-analysis of epidemiological studies

Outcome of interest

No. of studies

OR (95 % CI)

p heterogenity

I 2 (%)

p for interaction

Total dietary fiber

17

0.89 (0.77, 1.01)

0.005

53.6

 

Study design

 Cohort

5

0.94 (0.77, 1.11)

0.004

74.3

0.202

 Case-control

12

0.82 (0.68, 0.96)

0.277

17.0

 

Study quality

 Low

8

0.73 (0.56, 0.90)

0.335

12.2

0.033

 High

9

0.96 (0.83, 1.08)

0.04

51.7

 

Geographical region

 Europe

7

0.90 (0.71, 1.09)

0.01

63.5

0.937

 North America

6

0.90 (0.64, 1.16)

0.059

53.1

 

 Japan

2

0.95 (0.72, 1.17)

0.41

0

 

Assessment

 Interview

11

0.94 (0.79, 1.10)

0.313

13.8

0.931

 Questionnaire

4

0.93 (0.76, 1.09)

0.02

69.7

 

Family history

     

 Yes

8

0.84 (0.62, 1.05)

0.002

69.4

0.44

 No

9

0.94 (0.81, 1.08)

0.187

29.0

 

BMI

 Yes

8

0.87 (0.66, 1.08)

0.001

70.3

0.695

 No

9

0.92 (0.79, 1.06)

0.21

26.4

 

Energy intake

 Yes

14

0.91 (0.78, 1.04)

0.007

55.1

0.507

 No

3

0.81 (0.54, 1.07)

0.14

49.2

 

Multiple confoundersa

 Yes

6

0.82 (0.54, 1.09)

0.306

14.4

0.387

 No

11

0.95 (0.84, 1.05)

<0.001

77.7

 

Tumor stage

 Local

3

0.98 (0.89, 1.08)

0.24

30.5

0.562

 Advanced

4

0.93 (0.79, 1.07)

0.24

29.3

 

Source of intake

 Cereal fiber

3

1.05 (0.94, 1.16)

0.52

0

0.02

 Fruit fiber

3

0.92 (0.81, 1.03)

0.55

0

 

 Vegetable fiber

3

0.87 (0.53, 1.21)

0.001

84.8

 

 Legume fiber

1

0.55 (0.32, 0.95)

NA

NA

 

Solubility

 Soluble fiber

2

0.87 (0.52, 1.22)

0.13

57.2

0.777

 Insoluble fiber

3

0.80 (0.46, 1.13)

0.005

81.0

 
  1. aMultiple confounders refer to effect estimates adjusted for at least family history, BMI, and energy intake