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