After adjustment for potential confounders, taking 600 IU of vitamin E every other day was not associated with incident heart failure (HR 0.93, 95% CI 0.71 to 1.21, P=0.59), according to Claudia Chae, MD, MPH, of Massachusetts General Hospital in Boston, and colleagues.
But because there were relatively few heart failure events during follow-up, a small-to-moderate effect of supplementation could not be excluded, the researchers reported online in Circulation: Heart Failure.
Background—Oxidative
stress may contribute to the development of heart failure (HF);
however, an increased risk of HF has been observed
with antioxidant therapy in secondary
prevention trials. No large clinical trials have addressed the role of
antioxidant therapy
in the primary prevention of HF.
Methods and Results—We
examined the effect of vitamin E and HF risk in 39 815 initially
healthy women, aged at least 45 years at baseline, who
were enrolled in the Women's Health Study, a
randomized, double-blind, placebo-controlled trial of vitamin E (600 IU
every
other day). Over a median follow-up of 10.2
years, there were 220 incident HF events. In proportional hazards
models, adjusting
for age and randomized aspirin and beta
carotene treatment, vitamin E assignment did not significantly affect HF
risk (hazards
ratio [HR], 0.93; 95% CI, 0.71–1.21; P=0.59).
These results did not change with multivariate adjustment for other
risk factors, including interim myocardial infarction.
In a prespecified subgroup analysis, vitamin E
was inversely related to developing HF with normal ejection fraction
(≥50%)
with HR 0.59 (95% CI, 0.38–0.92; P=0.02), but there was no statistically significant effect on the risk of developing systolic HF (HR, 1.26; 95% CI, 0.84–1.89;
P=0.26).
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