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 µg/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 (β = - 0.09; p = 0.016). In the normal selenium group, baseline (but not 10 years) blood pressure also associated negatively with baseline selenium (β = - 0.09; p = 0.007). Both IMT (β = 0.12; p = 0.001) and CSWA (β = 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.
Keywords: Arterial stiffness; Atherosclerosis; Blood pressure; Carotid intima media thickness; Micronutrient; Pulse wave velocity.