Eighty-four RCTs were included in the review.
One third of trials achieved a Jadad score or 3 or more.
Vitamin E alone versus placebo: all-cause mortality.
There was no statistically significant difference between vitamin E and placebo in terms of all-cause mortality (5 trials; relative risk ratio 0.96, 95% CI: 0.84, 1.10). There was no significant heterogeneity. Sensitivity analyses did not alter these results. There was no evidence of publication bias. Three trials that were not included in the meta-analysis also showed no significant difference between vitamin E and placebo in terms of all-cause mortality.
Vitamin E in combination versus placebo: all-cause mortality.
There were insufficient trials of sufficient similarity to pool using meta-analysis. One trial reported statistically significant benefits for vitamin E in combination with omega-3 polyunsaturated fatty acids on all-cause mortality, while another reported statistically significant benefits for vitamin E in combination with beta-carotene and selenium on all-cause mortality. The other three trials reported no statistically significant benefit or adverse effect on all-cause mortality.
Vitamin E alone versus placebo: cardiovascular deaths.
There was no statistically significant difference between vitamin E and placebo in terms of cardiovascular deaths (5 trials; relative risk ratio 0.97, 95% CI: 0.80, 1.19). There was no significant heterogeneity. Sensitivity analyses did not alter these results. There was no evidence of publication bias.
Vitamin E in combination versus placebo: cardiovascular deaths.
There was no statistically significant difference between vitamin E in combination and placebo in terms of cardiovascular deaths (4 trials; relative risk ratio 1.03, 95% CI: 0.81, 1.32). There was evidence of significant heterogeneity (P=0.02). There was no evidence of publication bias.
Vitamin E alone versus placebo: fatal MI.
There was no statistically significant difference between vitamin E and placebo in terms of fatal MI (5 trials; relative risk ratio 0.97, 95% CI: 0.74, 1.27). There was evidence of significant heterogeneity (P=0.03). Sensitivity analyses did not alter these results. There was no evidence of publication bias. Two trials that were not included in the meta-analysis also showed no significant difference between vitamin E and placebo in terms of fatal MI.
Vitamin E in combination versus placebo: fatal MI.
There was no statistically significant difference between vitamin E in combination and placebo in terms of fatal MI (4 trials; relative risk ratio 1.02, 95% CI: 0.77, 1.37). There was evidence of significant heterogeneity (P=0.01). Sensitivity analyses did not alter these results. There was no evidence of publication bias. An additional trial that was not included in the meta-analysis also showed no significant difference between vitamin E in combination and placebo in terms of fatal MI.
Vitamin E alone versus placebo: nonfatal MI.
There was no statistically significant difference between vitamin E and placebo in terms of nonfatal MI (5 trials; relative risk ratio 0.72, 95% CI: 0.51, 1.02). There was evidence of significant heterogeneity (P=0.001). Sensitivity analyses did not alter these results. There was no evidence of publication bias. Two additional trials that were not included in the meta-analysis also showed no significant difference between vitamin E and placebo in terms of nonfatal MI.
Vitamin E in combination versus placebo: nonfatal MI.
There was no statistically significant difference between vitamin E in combination and placebo in terms of nonfatal MI (4 trials; relative risk ratio 0.99, 95% CI: 0.89, 1.10). There was no evidence of significant heterogeneity. There was no evidence of publication bias.
Vitamin E trials that reported on lipids as an outcome.
There was no statistically significant effect of vitamin E alone, or in combination with other antioxidants, in doses ranging from 100 IU to 1,200 IU, on serum lipids. Two large trials that were not included in the meta-analysis showed clinically insignificant, but statistically significant, changes in serum lipids.