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).