Plasma vitamin C, but not vitamin E, is associated with reduced risk of heart failure in older men.

BACKGROUND: Oxidative stress has been implicated in the pathogenesis of heart failure (HF). However, data on the association between antioxidant intakes and circulating levels and risk of incident HF in the older general population are limited. We have examined prospectively the associations between plasma vitamin C and E, dietary intakes of vitamin C and E, and incident HF. METHODS AND RESULTS: Prospective study of 3919 men aged 60 to 79 years with no prevalent HF followed up for a mean period of 11 years, in whom there were 263 cases with incident HF. Higher plasma vitamin C level was associated with significantly lower risk of incident HF in both men with and without previous myocardial infarction after adjustment for lifestyle characteristics, diabetes mellitus, blood lipids, blood pressure, and heart rate (hazards ratio [95% confidence interval], 0.81 [0.70, 0.93] and 0.75 [0.59, 0.97] for 1 SD increase in log vitamin C, respectively). Plasma vitamin E and dietary vitamin C intake showed no association with HF. High levels of dietary vitamin E intake (which correlated weakly with plasma vitamin E) were associated with increased risk of HF in men with no previous myocardial infarction even after adjustment (adjusted hazards ratio [95% confidence interval], 1.23 [1.06, 1.42] for 1 SD increase). CONCLUSIONS: Higher plasma vitamin C is associated with a reduced risk of HF in older men with and without myocardial infarction. High intake of dietary vitamin E may be associated with increased HF risk. Primary intervention trials assessing the effect of vitamin C supplements on HF risk in the elderly are needed.

Hepatic enzymes, the metabolic syndrome, and the risk of type 2 diabetes in older men.

OBJECTIVE: We have examined the relationship between hepatic enzymes, the metabolic syndrome, insulin resistance, and type 2 diabetes and assessed the potential of hepatic enzyme measurements in determining diabetes risk. RESEARCH DESIGN AND METHODS: We conducted a prospective study of 3,500 nondiabetic men aged 60-79 years who were followed-up for a mean period of 5 years and in whom there were 100 incident type 2 diabetes cases. RESULTS: In cross-sectional analyses, alanine aminotransferase (ALT) and gamma-glutamyltransferase (GGT) were strongly associated with obesity, insulin resistance, and the metabolic syndrome. Prospectively, the risk of type 2 diabetes significantly increased with increasing levels of ALT and GGT even after adjustment for confounders including BMI (top versus bottom quarter ALT: relative risk 2.72 [95% CI 1.47-5.02]; GGT: 3.68 [1.68-8.04]). Additional adjustment for insulin resistance attenuated the effects, but the relationships with ALT and GGT remained significant (1.91 [1.01-3.60] and 2.69 [1.21-5.97], respectively). Further adjustment for inflammatory markers (C-reactive protein) made minor differences. Among high-risk subjects (obese men or those with the metabolic syndrome), elevated GGT and ALT enhanced the prediction of diabetes risk. CONCLUSIONS: Elevated levels of ALT and GGT within the normal range are independent predictors of type 2 diabetes in older men and are useful additional measures in identifying those at high risk of diabetes.