Table 2.
Meta-analysis of the MTHFR C677T polymorphism and late-onset Alzheimer’s disease susceptibility
| Comparison | Subgroup | Studies | Test of heterogeneity | Test of association | Model | Publication bias | ||
|---|---|---|---|---|---|---|---|---|
| P Value | I2(%) | OR (95%CI) | P Value | Egger | ||||
| T vs. C | Overall | 14 | <0.001 | 80.6 | 1.16(0.95-1.41) | 0.147 | R | 0.839 |
| Asian | 4 | 0.022 | 68.8 | 1.43(1.09-1.87) | 0.009 | R | - | |
| Caucasian | 8 | <0.001 | 80.9 | 1.09(0.89-1.34) | 0.648 | R | - | |
| APOE ɛ4 carrier non-APOE ɛ4 | 4 | 0.309 | 16.5 | 1.47(1.14-1.91) | 0.003 | F | - | |
| carrier Overall | 4 | 0.241 | 28.5 | 1.31(1.12-1.54) | 0.001 | F | - | |
| TC vs. CC | Asian | 14 | 0.009 | 53.8 | 1.22(1.00-1.49) | 0.049 | R | 0.862 |
| Caucasian | 4 | 0.403 | 0 | 1.26(1.01-1.57) | 0.037 | R | - | |
| APOE ɛ4 carrier non-APOE ɛ4 | 8 | 0.016 | 59.4 | 1.05(0.80-1.39) | 0.706 | R | - | |
| carrier Overall | 4 | 0.212 | 33.4 | 1.54(1.04-2.28) | 0.030 | F | - | |
| Asian | 4 | 0.922 | 0 | 1.22(0.94-1.59) | 0.132 | F | - | |
| TT vs. CC | Caucasian | 14 | <0.001 | 75.4 | 1.23(0.84-1.81) | 0.286 | R | 0.915 |
| APOE ɛ4 carrier non-APOE ɛ4 | 4 | 0.027 | 67.2 | 2.09(1.16-3.77) | 0.014 | R | - | |
| carrier Overall | 8 | <0.001 | 78.7 | 0.84(0.49-1.42) | 0.507 | R | - | |
| Asian | 4 | 0.607 | 0 | 1.97(1.15-3.37) | 0.013 | F | - | |
| Caucasian | 4 | 0.094 | 53.0 | 2.06(1.23-3.47) | 0.006 | R | - | |
| TC+TT vs | APOE ɛ4 carrier non-APOE ɛ4 | 14 | <0.001 | 73.1 | 1.24(0.97-1.58) | 0.090 | R | 0.878 |
| CC | carrier Overall | 4 | 0.208 | 34.1 | 1.43(1.10-1.85) | 0.007 | R | - |
| Asian | 8 | <0.001 | 77.6 | 0.98(0.69-1.39) | 0.912 | R | - | |
| Caucasian | 4 | 0.347 | 9.3 | 1.67(1.16-2.42) | 0.006 | F | - | |
| APOE ɛ4 carrier non-APOE ɛ4 | 4 | 0.973 | 0 | 1.38(1.08-1.77) | 0.011 | F | - | |
| TT vs | carrier | 14 | <0.001 | 68.3 | 1.11(0.82-1.51) | 0.496 | R | 0.954 |
| TC+CC | 4 | 0.022 | 68.9 | 1.82(1.05-3.15) | 0.032 | R | - | |
| 8 | 0.002 | 69.9 | 0.84(0.56-1.26) | 0.409 | R | - | ||
| 4 | 0.262 | 25.0 | 1.58(0.98-2.56) | 0.061 | F | - | ||
| 4 | 0.011 | 73.0 | 1.83(1.02-3.30) | 0.044 | R | - | ||
Abbreviations: APOE, Apolipoprotein E; OR, odds ratio; CI, confidence interval; F, fixed-effects model; R, random-effects model; NA, not available.