Associations of selenium status with cardiometabolic risk factors: an 8-year follow-up analysis of the Olivetti Heart study.

Objective: High selenium status has been associated with adverse cardiometabolic outcomes in selenium-replete populations such as the US. In populations with lower selenium status such as in Italy, there is little epidemiological evidence about the association of selenium with cardiometabolic risk factors. We therefore examined cross-sectional and prospective relationships of serum selenium concentrations with cardiometabolic risk factors including blood pressure, diabetes and blood lipids in the Olivetti Heart Study.

Methods: The study population consisted of 445 adult male individuals for whom baseline serum selenium measurement and cardiometabolic risk factors at baseline (1994-1995) and follow-up examination (2002-2004: average follow-up=8 years) were available. Serum selenium was measured by atomic absorption spectrophotometry.

Results: Average serum selenium concentration at baseline was 77.5 ± 18.4 μg/L. In cross-sectional analyses, serum selenium levels were positively associated with serum total cholesterol (p for trend <0.0001) and prevalent diabetes (p for trend <0.05). In prospective analysis, serum selenium at baseline was likewise a strong predictor of serum total cholesterol (p=0.002) and LDL-cholesterol (p=0.001) at follow-up, after adjustment for age, BMI, cigarette smoking, physical activity, and lipid-lowering medication. These associations, however, were no longer significant after additional adjustment for baseline blood lipids. Selenium at baseline did not predict changes in total cholesterol levels between the baseline and follow-up examinations [β-coefficient (± SE)= 0.09 ± 0.12 (p=0.46)].

Conclusion: These findings corroborate previous cross-sectional associations of high selenium status with adverse blood lipid profile and diabetes. However, prospective analyses do not support the causality of these relations. Randomized and experimental evidence is necessary to clarify the mechanisms underlying the observed cross-sectional associations.