Plasma retinol: A novel marker for cardiovascular disease mortality in Australian adults

Background and aims: Vitamin A affects inflammation and immune function and is thus a factor of interest in relation to cardiovascular disease (CVD). As vitamin A circulates in the plasma in the form of retinol, this study aims to describe the relationship between plasma retinol and the 5-year incidence of CVD mortality. Methods and results: Community-dwelling adults (n = 441, 45% with type 2 diabetes) were recruited in Melbourne, assessed at baseline and followed for 5 years. At baseline, CVD risk factors were assessed by clinical evaluation, by personal lifestyle questionnaire and from biochemistry (plasma fasting glucose, lipids, total homocysteine, C-reactive protein, retinol and carotenoids plus the urinary albumin excretion rate over 24 h.). Dietary intake was assessed by a validated food frequency questionnaire. CVD mortality over 5-years was determined by consulting state or national registries. The majority of participants had adequate plasma retinol concentrations (>= 30 mu g/dL). The final Cox regression model indicated that those in the highest tertile of plasma retinol (mean +/- SD) 76 +/- 14 mu g/dL) had a significantly lower risk of 5-year CVD mortality (hazard ratio 0.27 [95% confidence interval 0.11, 0.68], P = 0.005), an effect that was not readily explained in terms of traditional CVD risk factors or dietary intake. Conclusion: In well-nourished older Australian adults, plasma retinol was inversely associated with CVD mortality via mechanisms apparently unrelated to established CVD risk factors and dietary intake. (C) 2011 Elsevier B.V. All rights reserved.