Table 2 Summary of the outcomes of each meta-analysis. Significant P values of the effect size are in bold
| Â | Measured SCFA | Number of Studies | Heterogeneity (I2 %, P value) | Statistical Model | Effect size (SMD [95% CI], P value) |
|---|---|---|---|---|---|
CRC risk | Acetic acid | 3 | 99, < 0.00001 | Random effect | 2.63 [− 1.82 to 7.08], 0.25 |
Propionic acid | 3 | 99, < 0.00001 | Random effect | 2.33 [− 2.33 to 7.00], 0.33 | |
Butyric acid | 5 | 99, < 0.00001 | Random effect | 1.47 [− 0.80 to 3.73], 0.2 | |
Combineda | 11 | 99, < 0.00001 | Random effect | 2.02 [0.31 to 3.74], 0.02 | |
Total SCFA | 3 | 38, 0.2 | Random effect | 0.29 [− 0.13 to 0.72], 0.17 | |
Total SCFA | 3 | 38, 0.2 | Fixed effect | 0.25 [− 0.05 to 0.56], 0.11 | |
CRC incidence | Acetic acid | 4 | 60, 0.06 | Random effect | 0.61 [0.09 to 1.13], 0.02 |
Propionic acid | 4 | 62, 0.05 | Random effect | 0.32 [− 0.21 to 0.84], 0.24 | |
Butyric acid | 4 | 43, 0.15 | Random effect | 0.45 [0.02 to 0.88], 0.04 | |
Combineda | 12 | 51, 0.02 | Random effect | 0.45 [0.19 to 0.72], 0.0009 | |
Butyric acid | 4 | 43, 0.15 | Fixed effect | 0.42 [0.1 to 0.74], 0.009 |