Table 2 Subgroup analyses for the effect of VE supplementation on MDA levels
Subgroup analyses | Number of trials | SMD | 95% CI | I2 value |
|---|---|---|---|---|
Route | ||||
 IM | 5 | −3.34 | −4.73, − 1.95 | 81 |
 Oral | 11 | −1.16 | − 1.86, − 0.46 | 90 |
MDA biomarker | ||||
 Serum/plasma | 11 | −0.79 | −0.40, − 0.19 | 90 |
 Non-serum/plasma | 7 | −3.05 | −4.21, −1.89 | 78 |
Duration | ||||
  ≤ 1 month | 8 | −2.29 | −3.34, −1.25 | 87 |
  > 1 month | 10 | −1.01 | −1.75, −0.28 | 91 |
Co-supplementation | ||||
 Monotherapy | 11 | −1.52 | −2.32, −0.71 | 90 |
 Combination | 7 | −1.69 | −3.03, −0.35 | 92 |
Vitamin E form (if known) | ||||
 Synthetic | 6 | −2.84 | −4.33, −1.35 | 90 |
 Natural | 6 | −0.58 | −1.26, 0.10 | 82 |
Study Design | ||||
 RCT | 4 | −0.05 | − 0.33, 0.22 | 33 |
 Non-RCT | 12 | −2.53 | −3.38, −1.67 | 87 |