Table 2 Number and percentage of meta-analyses overall and by cancer type that meet the individual and the overall criteria used for the grading of the evidence on diet and cancer risk.

From: An umbrella review of the evidence associating diet and cancer risk at 11 anatomical sites

 

Total (n = 860)

Head and necka (n = 38)

Esophageal (n = 48)

Stomach (n = 122)

Colorectal (n = 221)

Liver (n = 20)

Gallbladder (n = 2)

Lung (n = 144)

Skin (n = 18)

Breast (n = 163)

Kidney (n = 41)

Urinary bladder (n = 43)

Criterion

P value <10−6, n (%)

25 (2.9)

5 (13.2)

2 (4.2)

0 (0)

12 (5.4)

2 (10)

0 (0)

0 (0)

1 (5.6)

3 (1.8)

0 (0)

0 (0)

P value <10−3, n (%)

75 (8.7)

11 (28.9)

6 (12.5)

2 (1.6)

24 (10.9)

6 (30)

0 (0)

11 (7.6)

4 (2.2)

11 (6.7)

0 (0)

0 (0)

P value <0.05, n (%)

247 (28.7)

28 (73.7)

17 (35.4)

19 (15.6)

69 (31.2)

10 (50)

0 (0)

54 (37.5)

6 (3.3)

35 (21.5)

7 (17.1)

2 (4.7)

I2 > 50%, n (%)

227 (26.4)

15 (39.5)

14 (29.2)

25 (20.5)

44 (20)

7 (35)

0 (0)

45 (31.3)

6 (3.3)

46 (28.2)

12 (29.3)

13 (30.2)

I2 ≤ 25%, n (%)

450 (52.3)

18 (47.4)

27 (56.3)

77 (63.1)

115 (52.0)

8 (40)

2 (100)

73 (50.7)

8 (4.4)

79 (48.5)

23 (56.1)

20 (46.5)

Prediction interval excluding the null, n (%)

46 (5.3)

1 (7.9)

1 (2.1)

4 (3.3)

22 (10)

2 (10)

0 (0)

5 (3.5)

0 (0)

10 (6.1)

0 (0)

1 (2.3)

Evidence of small study biasb, n (%)

69 (8.0)

5 (13.2)

7 (14.9)

7 (5.4)

13 (5.9)

2 (10)

0 (0)

19 (13.2)

2 (1.1)

6 (3.7)

5 (12.2)

3 (7.0)

Evidence of excess significance biasc, n (%)

121 (14.1)

15 (39.5)

6 (12.5)

12 (9.8)

23 (10.4)

6 (30)

0 (0)

32 (22.2)

4 (2.2)

20 (12.3)

3 (7.3)

0 (0)

Overall grading

Not significant, n (%)

613 (71.3)

10 (26.3)

31 (64.6)

103 (84.4)

152 (68.8)

10 (50.0)

2 (100)

90 (62.5)

12 (66.7)

128 (78.5)

34 (82.9)

41 (95.4)

Weak, n (%)

182 (21.2)

23 (60.5)

12 (25.0)

17 (13.9)

46 (20.8)

5 (25.0)

0 (0)

44 (30.6)

2 (11.1)

24 (14.7)

7 (17.1)

2 (4.7)

Suggestive, n (%)

42 (4.9)

1 (2.6)

4 (8.3)

2 (1.6)

11 (5.0)

3 (15.0)

0 (0)

10 (6.9)

3 (16.7)

8 (4.9)

0 (0)

0 (0)

Highly suggestive, n (%)

13 (1.5)

4 (10.5)

1 (2.1)

0 (0)

4 (1.8)

2 (10.0)

0 (0)

0 (0)

1 (5.6)

1 (0.6)

0 (0)

0 (0)

Strong, n (%)

10 (1.2)

0 (0)

0 (0)

0 (0)

8 (3.6)

0 (0)

0 (0)

0 (0)

0 (0)

2 (1.2)

0 (0)

0 (0)

  1. aThis report presents results for cancers of mouth, pharynx, larynx, and upper aerodigestive tract.
  2. bSmall study bias is based on the P value from the Egger’s regression asymmetry test (two-sided P value ≤0.1) and the random-effects summary estimate was larger compared to the point estimate of the largest study in a meta-analysis.
  3. cExcess significance bias is based on the P value (two-sided P value ≤0.1) of the excess significance test using the largest study (smallest standard error) in a meta-analysis as the plausible effect size.
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