Low plasma selenium concentrations and mortality among older community-dwelling adults: the InCHIANTI Study

Abstract

Aims: We examined the relationship between plasma selenium levels at enrollment and all-cause mortality over a 6-year period among participants in the InCHIANTI study.

Methods: 1042 men and women > or =65 years from the InCHIANTI study, a population- based study of older adults living in the Chianti region of Tuscany, a population-based cohort in Tuscany, Italy. Plasma selenium was measured at enrollment (1998-2000), and vital status was ascertained until May 2006.

Results: During follow-up, 237 participants (22.7%) died. At enrollment, mean (SD) plasma selenium concentrations among participants who survived or died were 0.96 (0.14) and 0.87 (0.18) micromol/L (p<0.0001), respectively. The proportion of participants who died, from lowest to highest quartile of selenium, was 41.3, 27.0, 18.1 and 13.5% (p<0.0001 by Mantel-Haenszel chi-square). After adjusting for age, sex, education, and chronic diseases, adults in the lowest quartile of plasma selenium at enrollment had higher mortality compared with those in the highest quartile (Hazard Ratio (HR) 1.60, 95% Confidence Interval (CI) 1.04-2.47, p=0.034).

Conclusion: Low plasma selenium may be an independent predictor of mortality among older adults living in the community.

Fig. 1

Distribution of selenium level in whole population with aging.

Fig. 2

Kaplan-Meyer survival curves of older adults by quartile of plasma selenium at enrollment (Log-Rank: 38.31, p<0.0001 by log-rank test from highest to lowest quartile of selenium).