The Melbourne Atherosclerosis Vitamin E Trial (MAVET): a study of high dose vitamin E in smokers

Abstract

Our aim was to evaluate whether vitamin E (500 IU) slowed the progression of carotid atherosclerosis in a population of chronic smokers over 4 years as measured by ultrasound determination of carotid intima-media thickness (IMT) and systemic arterial compliance (SAC). The Melbourne Atherosclerosis Vitamin E Trial (MAVET) was a randomized, double-blind, placebo-controlled trial in which 409 male and female smokers aged 55 years and over were randomized to receive 500 IU per day of natural vitamin E or placebo. The primary endpoint was progression of carotid atherosclerosis determined by intima-media thickness of the right common carotid artery. Secondary outcomes were change in systemic arterial compliance and low-density lipoprotein (LDL) oxidative susceptibility over time. The mean increase in intima-media thickness over time in the vitamin E group was 0.0041 mm/year faster than placebo (95% confidence interval -0.0021 to 0.0102 mm/year, P = 0.20). Similarly, a non-significant difference between vitamin E and placebo was found for rate of change in systemic arterial compliance (P = 0.11). Vitamin E supplementation did, however, significantly reduce LDL oxidative susceptibility (P < 0.001). Vitamin E supplementation is ineffective in reducing the progression of carotid atherosclerosis as measured by intima-media thickness in chronic smokers. This finding extends our knowledge of lack of effectiveness of vitamin E supplementation in populations with high oxidant stress.