Table 2 Summary relative risk estimates (SRRE), 95 % confidence intervals (CI), p-values for heterogeneity and I² statistics for red and processed meat intake and prostate cancer (high vs. low exposure unless otherwise noted)

 Total red meat and total prostate cancer (n = 10)

1.02

0.92–1.12

0.006; 61.0 %

   Per 1 serving/day increase

0.96

0.91–1.00

   Intake of 0–0.50 servings/day (n = 5)

1.41

1.09–1.81

0.189; 34.85 %

   Intake of >0.50–1.0 servings/day (n = 13)

1.02

0.98–1.05

0.735; 0.00 %

   Intake of >1.0–1.5 servings/day (n = 10)

1.01

0.93–1.10

0.077; 42.07 %

   Intake of >1.0 servings/day (n = 7)

0.88

0.75–1.04

0.005; 67.68 %

 Total red meat and non-advanced prostate cancer (n = 3)

0.98

0.63–1.53

0.051; 66.3 %

   Per 1 serving/day increase

0.71

0.46–1.10

   Intake of <1 serving/day (n = 4)

1.10

0.92–1.31

0.619; 0.00 %

   Intake of >1 serving/day (n = 5)

0.89

0.66–1.19

0.060; 55.69 %

 Total red meat and advanced prostate cancer (n = 9)

1.01

0.86–1.17

0.177; 30.2 %

   Per 1 serving/day increase

0.97

0.91–1.04

   Intake of 0–0.75 servings/day (n = 9)

1.08

0.94–1.23

0.319; 13.78 %

   Intake of >0.75–1.0 servings/day (n = 4)

1.06

0.92–1.23

0.697; 0.00 %

   Intake of >1.0–1.5 servings/day (n = 8)

1.04

0.92–1.18

0.481; 0.00 %

   Intake of >1.0 servings/day (n = 4)

1.14

0.95–1.37

0.328; 12.95 %

 Total red meat and fatal prostate cancer (n = 3)

1.06

0.82–1.37

0.35; 4.80 %

   Per 1 serving/day increase

1.05

0.73–1.52

   Intake of <1 serving/day (n = 5)

1.09

0.91–1.30

0.350; 9.89 %

   Intake of >1 serving/day (n = 5)

1.15

0.96–1.38

0.474; 0.00 %

 Fresh red meat and total prostate cancer (n = 9)

1.06

0.97–1.16

0.113; 38.3 %

   Per 1 serving/day increase

0.91

0.81–1.03

   Intake of 0- < 0.25 servings/day (n = 9)

1.08

0.97–1.19

0.924; 0.00 %

   Intake of 0.25- < 0.5 servings/day (n = 8)

1.07

1.02–1.13

0.519; 0.00 %

   Intake of 0.5–0.75 servings/day (n = 6)

1.04

0.97–1.12

0.363; 8.28 %

   Intake of >0.75 servings/day (n = 9)

1.07

0.95–1.19

0.171; 30.95 %

 Fresh red meat and advanced prostate cancer (n = 6)

1.01

0.86–1.20

0.180; 34.107 %

   Per 1 serving/day increase

0.88

0.69–1.12

   Intake of 0–0.25 servings/day (n = 9)

1.14

0.97–1.34

0.776; 0.00 %

   Intake of >0.25–0.50 servings/day (n = 8)

0.99

0.89–1.10

0.543; 0.00 %

   Intake of >0.50 servings/day (n = 10)

0.99

0.89–1.11

0.398; 4.66 %

 Processed red meat and total prostate cancer (n = 11)

1.05

1.01–1.10

0.406; 3.38 %

   Per 1 serving/day increase

1.01

0.96–1.05

   Intake of 0–0.25 servings/day (n = 9)

1.05

0.99–1.10

0.369; 7.93 %

   Intake of >0.25–0.50 servings/day (n = 12)

1.05

1.00–1.09

0.407; 3.91 %

   Intake of >0.50–0.75 servings/day (n = 6)

1.02

0.97–1.07

0.506; 0.00 %

   Intake of >0.75 servings/day (n = 10)

1.04

0.99–1.10

0.176; 29.20 %

 Processed meat and advanced prostate cancer (n = 8)

1.12

0.95–1.33

0.040; 52.4 %

   Per 1 serving/day increase

1.10

0.98–1.24

   Intake of 0–0.25 servings/day (n = 12)

0.95

0.80–1.12

0.004; 60.09 %

   Intake of >0.25–0.50 servings/day (n = 9)

1.07

0.90–1.26

0.009; 60.61 %

   Intake of >0.50 servings/day (n = 8)

1.13

0.99–1.29

0.116; 39.42 %

 Processed meat and fatal prostate cancer (n = 2)

1.09

0.63–1.90

0.073; 68.9 %

   Per 1 serving/day increase

0.84

0.44–1.61

   Intake of <0.50 servings/day (n = 4)

0.93

0.75–1.15

0.276; 22.49 %

   Intake of >0.50 servings/day (n = 3)

0.95

0.69–1.30

0.112; 54.36 %