Selenium and mortality in the elderly: Results from the EVA study

Background: Inadequate plasma selenium can adversely affect the maintenance of optimal health; therefore, reported decreases in plasma selenium in an aging population are cause for concern. To further examine this hypothesis, we explored the relationships between plasma selenium and mortality in an elderly population: the EVA (Etude du Vieillissement Arteriel) study. Methods: The EVA study was a 9-year longitudinal study with 6 periods of follow-up. During the 2-year period from 1991 to 1993 (EVA0), 1389 men and women born between 1922 and 1932 were recruited. The effects of plasma selenium at baseline on mortality were determined by Cox proportional hazards regression analysis, adjusting for the following variables: sociodemographic characteristics, dietary habits, health, and cognitive factors. Results: During the 9-year follow-up, 101 study participants died. Baseline plasma selenium was higher in individuals who were alive at the end of follow-up [mean (SD), 1.10 (0.20) mu mol/L] than in those who died during the follow-up [1.01 (0.20) mu mol/L; P < 10(-4)]. Mortality rates were significantly higher in individuals with low selenium [increments = 0.2 mu mol/L; relative risk (RR) = 1.56 (95% confidence interval, 1.28-1.89)]. After we controlled for various potential confounding factors, this association remained significant [RR = 1.54.(1.25-1.88)]. When the underlying causes of death were considered, we found an association with cancer-related mortality [adjusted RR = 1.79 (1.32-2.44)]. Conclusions: Even if it is premature to present selenium as a longevity indicator in an elderly population, our results are in accordance those of large, interventional, randomized trials with selenium, which suggest that this essential trace element plays a role in health maintenance in aging individuals. (c) 2005 American Association for Clinical Chemistry.