Relatively high mortality risk in elderly Swedish subjects with low selenium status

U Alehagen, P Johansson, M Björnstedt, A Rosén, C Post, J Aaseth

The daily dietary intake of selenium (Se), an essential trace element, is still low in Sweden in spite of decades of nutritional information campaigns and the effect of this on the public health is presently not well known. The objective of this study was to determine the serum Se levels in an elderly Swedish population and to analyze whether a low Se status had any influence on mortality. Six-hundred sixty-eight (n=668) elderly participants were invited from a municipality and evaluated in an observational study. Individuals were followed for 6.8 years and Se levels were re-evaluated in 98 individuals after 48 months. Clinical examination of all individuals included functional classification, echocardiography, electrocardiogram and serum Se measurement. All mortality was registered and endpoints of mortality were assessed by Kaplan-Meier plots, and Cox proportional hazard ratios adjusted for potential confounding factors were calculated. The mean serum Se level of the study population (n=668) was 67.1 μg/l, corresponding to relatively low Se intake. After adjustment for male gender, smoking, ischemic heart disease, diabetes, chronic obstructive pulmonary disease and impaired heart function, persons with serum Se in the lowest quartile had 43% (95% confidence interval (CI): 1.02-2.00) and 56% (95% CI: 1.03-2.36) increased risk for all-cause and cardiovascular mortality, respectively. The result was not driven by inflammatory effects on Se concentration in serum. The mean serum Se concentration in an elderly Swedish population was 67.1 μg/l, which is below the physiological saturation level for several selenoprotein enzymes. This result may suggest the value of modest Se supplementation in order to improve the health of the Swedish population.European Journal of Clinical Nutrition advance online publication, 24 June 2015; doi:10.1038/ejcn.2015.92.