Modification of the Effect of Vitamin E Supplementation on the Mortality of Male Smokers by Age and Dietary Vitamin C

Abstract

The Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study (1985–1993) recruited 29,133 Finnish male cigarette smokers, finding that vitamin E supplementation had no overall effect on mortality. The authors of this paper found that the effect of vitamin E on respiratory infections in ATBC Study participants was modified by age, smoking, and dietary vitamin C intake; therefore, they examined whether the effect of vitamin E supplementation on mortality is modified by the same variables. During a median follow-up time of 6.1 years, 3,571 deaths occurred. Age and dietary vitamin C intake had a second-order interaction with vitamin E supplementation of 50 mg/day. Among participants with a dietary vitamin C intake above the median of 90 mg/day, vitamin E increased mortality among those aged 50–62 years by 19% (95% confidence interval: 5, 35), whereas vitamin E decreased mortality among those aged 66–69 years by 41% (95% CI: −56, −21). Vitamin E had no effect on participants who had a dietary vitamin C intake below the median. Smoking quantity did not modify the effect of vitamin E. This study provides strong evidence that the effect of vitamin E supplementation on mortality varies between different population groups. Further study is needed to confirm this heterogeneity.

The Effect of Vitamin E on Mortality Is Not Uniform across the Population

“…Vitamin E had no influence on mortality among those who had dietary vitamin C intake less than the median. The modifying effect of vitamin C was not explained by other substances in fruit and vegetables (5). The interaction between vitamins C and E is well documented (6,7), and may explain the role of vitamin C as a modifying factor for some vitamin E effects.…”

“…It is probable that the effects of vitamin E are modified by, for example, vitamin C as found in our study, but the effects seem to depend on the characteristics of population groups so that only the oldest people benefited (5, 10). Jiang et al (1) did not give any justification for dismissing the strong evidence of heterogeneity in the effects of low dose vitamin E on mortality (5,10).…”

Present trends in vitamin E research

“…Actually, the effect of vitamin E supplementation on morbidity and mortality varies between different population groups. More careful evaluation by subject stratification of ATBC study data showed that vitamin E may either prevent or increase the overall risk of mortality depending on age and vitamin C intake [116]. More in detail, when the dietary vitamin C intake was above the median of 90 mg/day, vitamin E increased mortality among those aged 50-62 years by 19% and decreased mortality among those aged 66-69 years by 41%.…”

Antioxidants: Friend or foe for tuberculosis patients

“…Clinical effect of vitamin E is not observed in recipients who consume less vitamin C containing diet [34]. It has been observed that vitamin E supplementation transiently increases the risk of active tuberculosis in heavy smokers if co-supplemented with vitamin C [35].…”