Table 2.
Characteristics | Subgroups | Studies (number) | WMD | 95% CI | pD | I2 | pH | pE |
---|---|---|---|---|---|---|---|---|
Cancer subtype | CRC | 20 | −0.736 | −1.519 to 0.047 | 0.065 | 94.0% | <0.001 | 0.514 |
CRA | 10 | −0.892 | −1.573 to −0.211 | 0.010 | 80.1% | <0.001 | 0.473 | |
Colon | 10 | −1.073 | −2.095 to −0.050 | 0.040 | 97.3% | <0.001 | 0.403 | |
Rectum | 4 | −0.681 | −1.358 to −0.005 | 0.048 | 75.4% | 0.007 | 0.778 | |
Region | East Asia | 6 | −1.707 | −2.979 to −0.436 | 0.008 | 95.1% | <0.001 | 0.213 |
America | 10 | −0.343 | −0.599 to −0.087 | 0.009 | 36.7% | 0.115 | 0.683 | |
Europe | 15 | −0.749 | −1.451 to −0.047 | 0.037 | 94.3% | <0.001 | 0.541 | |
Middle East | 10 | −0.787 | −3.015 to 1.442 | 0.489 | 97.1% | <0.001 | 0.787 | |
Study design | Retrospective | 22 | −1.179 | −2.536 to 0.177 | 0.088 | 96.2% | <0.001 | 0.489 |
Nested | 19 | −0.266 | −0.380 to −0.152 | <0.001 | 12.4% | 0.303 | 0.409 | |
Matching status | NA | 21 | −1.472 | −2.452 to −0.491 | 0.003 | 96.1% | <0.001 | 0.411 |
Yes | 20 | −0.099 | −0.389 to 0.191 | 0.504 | 79.0% | <0.001 | 0.693 | |
Sample source | Plasma | 18 | −0.714 | −1.358 to −0.070 | 0.030 | 95.1% | <0.001 | 0.783 |
Serum | 23 | −0.803 | −1.430 to −0.176 | 0.012 | 93.3% | <0.001 | 0.303 | |
Sample size (median) | ≤230 | 21 | −1.189 | −2.609 to 0.231 | 0.101 | 96.4% | <0.001 | 0.511 |
>230 | 20 | −0.271 | −0.385 to −0.157 | <0.001 | 12.1% | 0.304 | 0.262 | |
Gender | Men | 9 | −0.671 | −1.255 to −0.086 | 0.025 | 90.4% | <0.001 | 0.536 |
Women | 8 | −0.329 | −0.693 to 0.035 | 0.077 | 49.6% | <0.001 | 0.206 | |
BMI | <25 kg/m2 | 7 | −1.627 | −3.092 to −0.163 | 0.029 | 92.1% | <0.001 | 0.434 |
≥25 kg/m2 | 24 | −0.527 | −1.016 to −0.039 | 0.034 | 92.4% | <0.001 | 0.611 | |
WHR | <0.9 m | 5 | −0.878 | −1.798 to 0.043 | 0.062 | 94.7% | <0.001 | 0.112 |
≥0.9 m | 9 | −0.522 | −0.939 to −0.106 | 0.014 | 60.6% | 0.009 | 0.496 | |
DM | Without | 12 | −1.385 | −3.003 to 0.233 | 0.093 | 96.1% | <0.001 | 0.349 |
TNM stage | I–II | 9 | −1.280 | −2.115 to −0.446 | 0.003 | 90.1% | <0.001 | 0.103 |
III–IV | 9 | −1.196 | −2.033 to −0.358 | 0.005 | 92.6% | <0.001 | 0.219 |
Notes: pD, the p-value for WMD; I2, inconsistency index; pH, the p-value for heterogeneity; pE, the p-value for Egger’s regression asymmetry test.
Abbreviations: WMD, weighted mean difference; CI, confidence interval; CRC, colorectal cancer; CRA, colorectal adenoma; BMI, body mass index; WHR, waist–hip ratio; DM, diabetes mellitus; TNM, tumor node metastasis; NA, not available.