Inverse Association Between Baseline Plasma Selenium Concentrations and Risks of Renal Function Decline in Hypertensive Adults

BACKGROUND: The kidney has the highest level of selenium (Se) in the body, but the role of plasma Se in chronic kidney disease is uncertain. OBJECTIVE: We aimed to investigate the longitudinal association between baseline plasma Se and renal function decline in adults with hypertension and to explore possible effect modifiers. METHODS: This was a post hoc analysis of 935 men and women with hypertension aged 40 to 75 years from a folic-acid intervention trial (the China Stroke Primary Prevention Trial) in China. The baseline plasma Se was analyzed both as a continuous variable and as tertiles. The primary outcome was a rapid decline in renal function, defined as a mean decline in the estimated glomerular filtration rate of ≥ 5 mL/(min × 1.73 m(2)) per year. RESULTS: The median follow-up duration from baseline to outcome was 4.4 years. After multivariate adjustment, there was an inverse association between plasma Se and a rapid decline in renal function (per 10-unit increment; OR: 0.85; 95% CI: 0.73, 0.99). When the baseline plasma Se was assessed as tertiles, compared to the lowest tertile (<74.5 μg/L), a lower trend of the primary outcome was found in the second tertile (74.5 to < 89.4 μg/L; OR: 0.60; 95% CI: 0.34, 1.07) and the highest tertile (89.4 to <150 μg/L; OR: 0.42; 95% CI: 0.22, 0.80; P(trend) = 0.006). Furthermore, the Se-renal association was more pronounced among participants with folic acid treatment or with a higher baseline folate concentration (both P(interaction) values < 0.05). CONCLUSIONS: In this sample of Chinese adults with hypertension, baseline plasma Se concentrations were inversely associated with the risk of renal function decline. The China Stroke Primary Prevention Trial was registered at clinicaltrials.gov as NCT00794885.