Background
Methods
Literature search, study selection, and data extraction
Data analysis
Grading the evidence
Results
Literature selection
Characteristics of meta-analyses included in this umbrella review
Summary relative risk (95% CI) | P value | |||||||||
---|---|---|---|---|---|---|---|---|---|---|
Author, year | Cancer type | Unit of comparison | No of studies | No. of cases | Fixed-effects model | Random-effects model | Largest study | Fixed-effects model | Random-effects model | 95% PI |
Thomopoulos, 2015 [20] | Acute lymphocytic leukemia | H/L | 7 | 2453 | 1.43 (1.22, 1.68) | 1.44 (1.21, 1.71) | 1.30 (1.00, 1.70) | 9.28E-06 | 2.9E-05 | (1.09, 1.91) |
Thomopoulos, 2015 [20] | Acute myelogenous leukemia | H/L | 6 | 333 | 1.76 (1.17, 2.63) | 1.78 (0.87, 3.65) | 2.40 (1.30, 4.30) | 0.006 | 0.115 | (0.17, 18.39) |
Godos, 2017 [4] | Biliary tract cancer | H/L | 5 | 726 | 0.91 (0.69, 1.20) | 0.91 (0.69, 1.20) | 0.94 (0.64, 1.37) | 0.006 | 0.115 | (0.58, 1.43) |
Wu, 2015 [24] | Bladder cancer | H/L | 30 | 16,172 | 1.29 (1.19, 1.39) | 1.35 (1.20, 1.50) | 1.00 (0.83, 1.21) | 8.89E-11 | 1.54E-07 | (0.90, 2.00) |
Jiang, 2013 [9] | Breast cancer | H/L | 34 | 56,541 | 0.97 (0.93, 1.01) | 0.97 (0.93, 1.01) | 0.98 (0.91, 1.07) | 0.089 | 0.089 | (0.93, 1.01) |
Gan, 2017 [3] | Colon cancer | H/L | 16 | 13,853 | 0.91 (0.84, 0.98) | 0.92 (0.83, 1.02) | 0.92 (0.80, 1.06) | 0.011 | 0.097 | (0.72, 1.18) |
Li, 2013 [13] | Colorectal cancer | H/L | 40 | 25,965 | 0.89 (0.85, 0.94) | 0.88 (0.81, 0.96) | 0.90 (0.80, 1.02) | 1.37E-05 | 0.003 | (0.59, 1.30) |
Lukic, 2018 [8] | Endometrial cancer | H/L | 19 | 13,812 | 0.79 (0.74, 0.84) | 0.75 (0.70, 0.82) | 0.92 (0.82, 1.03) | 2.67E-14 | 2.90E-11 | (0.60, 0.93) |
Zheng, 2013 [28] | Esophageal cancer | H/L | 14 | 3575 | 0.90 (0.81, 1.00) | 0.84 (0.72, 0.98) | 1.13 (0.92, 1.37) | 0.047 | 0.028 | (0.55, 1.29) |
Botelho, 2006 [1] | Gastric cancer | H/L | 23 | 5611 | 0.96 (0.88, 1.06) | 0.97 (0.86, 1.09) | 0.93 (0.72, 1.21) | 0.422 | 0.593 | (0.67, 1.40) |
Malerba, 2013 [15] | Glioma | H/L | 6 | 255 | 1.01 (0.83, 1.22) | 1.01 (0.83, 1.22) | 0.98 (0.67, 1.41) | 0.943 | 0.943 | (0.77, 1.32) |
Wijarnpreecha, 2017 [23] | Kidney cancer | H/L | 22 | 11,087 | 1.00 (0.92, 1.09) | 0.99 (0.89, 1.11) | 1.33 (1.07, 1.66) | 0.971 | 0.909 | (0.71, 1.38) |
Ouyang, 2014 [16] | Laryngeal cancer | H/L | 8 | 2596 | 1.05 (0.94, 1.18) | 1.18 (0.87, 1.59) | 0.90 (0.80, 1.10) | 0.397 | 0.284 | (0.47, 2.93) |
Thomopoulos, 2015 [20] | Leukemia | H/L | 6 | 2303 | 1.41 (1.19, 1.66) | 1.57 (1.16, 2.11) | 1.10 (0.90, 1.50) | 5.27E-05 | 0.003 | (0.69, 3.56) |
Sang, 2013 [17] | Liver cancer | H/L | 16 | 3622 | 0.50 (0.42, 0.59) | 0.48 (0.40, 0.58) | 0.70 (0.50, 1.00) | 2.77E-16 | 8.84E-15 | (0.35, 0.67) |
Galarraga, 2016 [2] | Lung cancer | H/L | 21 | 19,892 | 1.08 (1.06, 1.11) | 1.26 (1.13, 1.41) | 1.04 (1.01, 1.07) | 1.84E-11 | 4.7E-05 | (0.82, 1.93) |
Han, 2016 [6] | Lymphoma | H/L | 7 | 1513 | 1.05 (0.90, 1.23) | 1.08 (0.76, 1.53) | 1.11 (0.90, 1.37) | 0.551 | 0.659 | (0.38, 3.05) |
Yew, 2016 [27] | Melanoma | H/L | 11 | 3787 | 0.76 (0.69, 0.84) | 0.75 (0.65, 0.87) | 0.80 (0.69, 0.93) | 1.39E-08 | 0.000151 | (0.50, 1.12) |
Vaseghi, 2016 [22] | Nonmelanoma | H/L | 6 | 104,770 | 0.86 (0.80, 0.93) | 0.87 (0.78, 0.98) | 0.83 (0.75, 0.92) | 0.000111 | 0.021 | (0.67, 1.13) |
Li, 2016 [11] | Oral cancer | H/L | 15 | 5021 | 0.63 (0.57, 0.71) | 0.63 (0.52, 0.75) | 0.51 (0.40, 0.64) | 7.3E-16 | 3.79E-07 | (0.36, 1.09) |
Miranda, 2017 [15] | Oral/Pharyngeal cancer | H/L | 17 | 5151 | 0.72 (0.64, 0.82) | 0.69 (0.57, 0.84) | 0.60 (0.45, 0.80) | 5.26E-07 | 0.000281 | (0.37, 1.29) |
Steevens, 2007 [18] | Ovarian cancer | H/L | 15 | 5479 | 1.11 (0.98, 1.27) | 1.18 (0.97, 1.44) | 0.93 (0.69, 1.26) | 0.115 | 0.101 | (0.63, 2.19) |
Turati, 2012 [21] | Pancreatic cancer | H/L | 54 | 10,594 | 1.14 (1.05, 1.24) | 1.13 (0.99, 1.29) | 0.95 (0.73, 1.23) | 0.002 | 0.063 | (0.59, 2.16) |
Xia, 2017 [26] | Prostate cancer | H/L | 27 | 42,399 | 1.02 (0.96, 1.07) | 1.07 (0.96, 1.18) | 0.94 (0.87, 1.02) | 0.585 | 0.228 | (0.74, 1.53) |
Gan, 2017 [3] | Rectal cancer | H/L | 15 | 6200 | 1.07 (0.97, 1.18) | 1.06 (0.95, 1.19) | 1.20 (1.00, 1.44) | 0.185 | 0.285 | (0.86, 1.31) |
Han, 2017 [5] | Thyroid cancer | H/L | 7 | 1039 | 0.91 (0.74, 1.12) | 0.91 (0.74, 1.12) | 1.00 (0.68, 1.48) | 0.37 | 0.37 | (0.70, 1.19) |
Li, 2013 [12] | Breast cancer | Per 1 cup | 24 | 46,812 | 0.99 (0.98, 1.00) | 0.99 (0.98, 1.00) | 0.99 (0.98, 1.01) | 0.009 | 0.009 | (0.98, 1.00) |
Gan, 2017 [3] | Colon cancer | Per 1 cup | 15 | 13,650 | 0.98 (0.97, 0.99) | 0.98 (0.97, 1.00) | 0.97 (0.95, 0.99) | 0.0006 | 0.019 | (0.95, 1.02) |
Gan, 2017 [3] | Colorectal cancer | Per 1 cup | 17 | 22,037 | 0.99 (0.98, 1.00) | 0.99 (0.98, 1.01) | 0.97 (0.96, 0.99) | 0.01 | 0.292 | (0.96, 1.03) |
Huang, 2013 [7] | Endometrial cancer | Per 1 cup | 7 | 3571 | 0.94 (0.91, 0.96) | 0.93 (0.90, 0.97) | 0.94 (0.90, 0.97) | 6.63E-07 | 0.000321 | (0.85, 1.02) |
Xie, 2014 [26] | Gastric cancer | Per 1 cup | 9 | 2344 | 1.00 (0.98, 1.03) | 1.02 (0.97, 1.06) | 0.97 (0.93, 1.01) | 0.806 | 0.482 | (0.90, 1.15) |
Malerba, 2013 [14] | Glioma | Per 1 cup | 4 | 1493 | 1.00 (0.97, 1.03) | 1.00 (0.96, 1.05) | 1.00 (0.96, 1.05) | 0.927 | 0.939 | (0.85, 1.19) |
Kennedy, 2017 [10] | Liver cancer | Per 1 cup | 17 | 4730 | 0.84 (0.82, 0.86) | 0.81 (0.77, 0.85) | 0.90 (0.86, 0.95) | 2.69E-36 | 1.2E-16 | (0.68, 0.95) |
Tang, 2010 [19] | Lung cancer | Per 1 cup | 9 | 3862 | 1.07 (1.04, 1.11) | 1.07 (1.02, 1.12) | 1.10 (1.03, 1.17) | 3E-05 | 0.006 | (0.95, 1.21) |
Turati, 2012 [21] | Pancreatic cancer | Per 1 cup | 28 | 6534 | 1.02 (1.00, 1.03) | 1.03 (0.99, 1.06) | 1.04 (1.00, 1.08) | 0.047 | 0.12 | (0.90, 1.17) |
Gan, 2017 [3] | Rectal cancer | Per 1 cup | 14 | 6134 | 1.01 (0.99, 1.03) | 1.01 (0.99, 1.03) | 0.95 (0.86, 1.07) | 0.263 | 0.211 | (0.98, 1.05) |
Evidence summary
Author, year | Cancer type | Unit of comparison | I2 (95%CI) | P for Q* | Egger’s P value | Observeda | Expecteda | P for TESb |
---|---|---|---|---|---|---|---|---|
Thomopoulos, 2015 [20] | Acute lymphocytic leukemia | H/L | 8 (0, 73) | 0.368 | 0.309 | 2 | 1.24 | – |
Thomopoulos, 2015 [20] | Acute myelogenous leukemia | H/L | 63 (2, 86) | 0.029 | 0.9 | 1 | 1.16 | 0.444 |
Godos, 2017 [4] | Biliary tract cancer | H/L | 0 (0, 79) | 0.849 | 0.073 | 0 | 0.42 | – |
Wu, 2015 [24] | Bladder cancer | H/L | 42 (11, 63) | 0.009 | 0.014 | 9 | 10.42 | – |
Jiang, 2013 [9] | Breast cancer | H/L | 0 (0, 39) | 0.485 | 0.374 | 4 | 5.64 | – |
Gan, 2017 [3] | Colon cancer | H/L | 30 (0, 62) | 0.124 | 0.699 | 3 | 3.14 | – |
Li, 2013 [13] | Colorectal cancer | H/L | 57 (38, 70) | < 0.001 | 0.419 | 11 | 10.27 | – |
Lukic, 2018 [8] | Endometrial cancer | H/L | 29 (0, 60) | 0.132 | 0.326 | 8 | 3.17 | 0.786 |
Zheng, 2013 [28] | Esophageal cancer | H/L | 42 (0, 69) | 0.049 | 0.038 | 3 | 4.88 | 0.008 |
Botelho, 2006 [1] | Gastric cancer | H/L | 34 (0, 61) | 0.055 | 0.695 | 3 | 5.13 | – |
Malerba, 2013 [15] | Glioma | H/L | 0 (0, 75) | 0.479 | 0.135 | 0 | 0.85 | – |
Wijarnpreecha, 2017 [23] | Kidney cancer | H/L | 35 (0, 62) | 0.052 | 0.882 | 2 | 8.51 | – |
Ouyang, 2014 [16] | Laryngeal cancer | H/L | 76 (53, 88) | < 0.001 | 0.329 | 2 | 2.83 | – |
Thomopoulos, 2015 [20] | Leukemia | H/L | 55 (0, 82) | 0.048 | 0.128 | 2 | 2.34 | – |
Sang, 2013 [17] | Liver cancer | H/L | 10 (0, 47) | 0.337 | 0.05 | 7 | 4.24 | 0.118 |
Galarraga, 2016 [2] | Lung cancer | H/L | 88 (84, 92) | < 0.001 | 0.104 | 9 | 9.29 | – |
Han, 2016 [6] | Lymphoma | H/L | 68 (30, 86) | 0.004 | 0.775 | 2 | 2.32 | – |
Yew, 2016 [27] | Melanoma | H/L | 46 (0, 73) | 0.048 | 0.824 | 5 | 2.7 | 0.107 |
Vaseghi, 2016 [22] | Nonmelanoma | H/L | 29 (0, 71) | 0.22 | 0.512 | 1 | 1.28 | – |
Li, 2016 [11] | Oral cancer | H/L | 53 (16, 74) | 0.008 | 0.685 | 7 | 4.89 | 0.245 |
Miranda, 2017 [15] | Oral/Pharyngeal cancer | H/L | 50 (13, 72) | 0.009 | 0.287 | 6 | 4.86 | 0.537 |
Steevens, 2007 [18] | Ovarian cancer | H/L | 51 (11, 73) | 0.012 | 0.047 | 3 | 4.57 | – |
Turati, 2012 [21] | Pancreatic cancer | H/L | 50 (32, 64) | < 0.001 | 0.876 | 12 | 14.86 | – |
Xia, 2017 [26] | Prostate cancer | H/L | 52 (32, 71) | 0.001 | 0.229 | 4 | 6.63 | – |
Gan, 2017 [3] | Rectal cancer | H/L | 13 (0, 51) | 0.308 | 0.822 | 1 | 3.13 | – |
Han, 2017 [5] | Thyroid cancer | H/L | 0 (0, 71) | 0.591 | 0.746 | 0 | 1 | – |
Li, 2013 [12] | Breast cancer | Per 1 cup | 0 (0, 45) | 0.796 | 0.619 | 0 | 3.30 | – |
Gan, 2017 [3] | Colon cancer | Per 1 cup | 23 (0, 58) | 0.203 | 0.818 | 3 | 3.00 | 0.999 |
Gan, 2017 [3] | Colorectal cancer | Per 1 cup | 34 (0, 63) | 0.081 | 0.434 | 3 | 4.80 | – |
Huang, 2013 [7] | Endometrial cancer | Per 1 cup | 35 (0, 73) | 0.161 | 0.274 | 3 | 1.30 | 0.098 |
Xie, 2014 [26] | Gastric cancer | Per 1 cup | 48 (0, 76) | 0.051 | 0.198 | 1 | 2.66 | – |
Malerba, 2013 [14] | Glioma | Per 1 cup | 44 (0, 81) | 0.15 | 0.961 | 0 | 0.83 | – |
Kennedy, 2017 [10] | Liver cancer | Per 1 cup | 59 (30, 76) | 0.001 | 0.00005093 | 13 | 7.22 | 0.005 |
Tang, 2010 [19] | Lung cancer | Per 1 cup | 41 (0, 73) | 0.092 | 0.499 | 3 | 2.21 | 0.543 |
Turati, 2012 [21] | Pancreatic cancer | Per 1 cup | 65 (47, 76) | < 0.001 | 0.326 | 4 | 8.67 | – |
Gan, 2017 [3] | Rectal cancer | Per 1 cup | 12 (0, 50) | 0.323 | 0.383 | 0 | 3.15 | – |
Excess significance test and publication bias
Evaluating the evidence
Criteria used | Decreased risk | Increased risk | |
---|---|---|---|
Strong | P in random-effects model < = 0.001 Number of cases > 1000 I2 < = 50% 95% predictive intervals exclude the null value Small study effects P > 0.1 Excess significance bias P > 0.1 | None | Acute lymphocytic leukemia (H/L) |
Highly suggestive | P in random-effects model < = 0.001Number of cases > 1000 I2 < = 75% | Endometrial cancer (H/L); Endometrial cancer (Per 1 cup); Liver cancer (H/L); Liver cancer (Per 1 cup); Melanoma (H/L); Oral cancer (H/L); Oral/pharyngeal cancer (H/L) | Bladder (H/L) |
Suggestive | P in random-effects model < = 0.001Number of cases > 500 | None | Lung cancer (H/L) |
Weak | P in random-effects model <= 0.05 | Breast cancer (Per 1 cup); Colon cancer (Per 1 cup); Colorectal cancer (H/L); Esophageal cancer (H/L); Nonmelanoma (H/L) | Leukemia (H/L); Lung (Per 1 cup) |
No association | P in random-effects model > 0.05 | Pancreatic cancer (H/L); Breast cancer (H/L); Colon cancer (H/L); Ovarian cancer (H/L); Acute myelogenous leukemia (H/L); Pancreatic cancer (Per 1 cup); Rectal cancer (Per 1 cup); Kidney cancer (H/L); Laryngeal cancer (H/L); Rectal cancer (H/L); Colorectal cancer (Per 1 cup); Thyroid cancer (H/L); Prostate cancer (H/L); Gastric cancer (Per 1 cup); Gastric cancer (H/L); Lymphoma (H/L); Glioma (Per 1 cup); Glioma (H/L); Biliary tract cancer (H/L). |