Selenium and large artery structure and function: a 10-year prospective study

Purpose Despite selenium's beneficial effects in counteracting oxidative stress, inflammation, and vascular endothelial dysfunction, controversial results exist regarding the long-term associations between selenium and atherosclerosis, arterial stiffness, and hypertension. We investigated in normal and selenium-deficient groups (and the total group), whether serum selenium relates to measures of large artery structure and function over 10 years. Methods This longitudinal study included black adults from rural and urban areas in South Africa. Serum selenium and blood pressure were measured at baseline (N=987). At follow-up, carotid intima media thickness (IMT), cross-sectional wall area (CSWA), carotid-femoral pulse wave velocity (c-fPWV), and blood pressure were measured (N=718). Selenium deficiency was classified as serum levels < 8 mu g/100 ml. Results In multivariable-adjusted regression analyses performed in the normal selenium group, c-fPWV after 10 years was negatively associated with baseline selenium (beta=-0.09; p=0.016). In the normal selenium group, baseline (but not 10 years) blood pressure also associated negatively with baseline selenium (beta=-0.09; p=0.007). Both IMT (beta=0.12; p=0.001) and CSWA (beta=0.10; p=0.003) after 10 years associated positively with baseline selenium in the total, normal, and selenium-deficient groups. Conclusion We found a long-term vascular protective association of selenium on arterial stiffness and blood pressure in Africans with normal selenium levels, supporting the notion that selenium fulfills a vascular protective role. In contrast, we found a potential detrimental association between selenium and carotid wall thickness, particularly evident in individuals within the highest quartile of serum selenium.