Plasma selenium and the risk of first stroke in adults with hypertension: a secondary analysis of the China Stroke Primary Prevention Trial.

BACKGROUND Previous studies indicated that selenium (Se) may play an important role in cardio-cerebrovascular disease. However, the relationship between circulating selenium and risk of first stroke remains inconclusive. OBJECTIVE We conducted a secondary analysis of the China Stroke Primary Prevention Trial (CSPPT), using a nested case-control design, and aimed to investigate the correlation between Se concentration and first stroke risk in adults with hypertension and examine the potential effect modifiers. METHODS In the CSPPT, a total of 20,702 adults with hypertension were randomly assigned to a double-blind, daily treatment with either 10 mg enalapril and 0.8 mg folic acid or 10 mg enalapril alone. A total of 618 first stroke cases and 618 controls matched for age, sex, treatment group, and study site were included in this study. RESULTS During a median follow-up duration of 4.5 years (IQR, 4.2-4.6 y), there was a significant inverse association between plasma Se and the risk of first stroke (per SD increment; adjusted OR: 0.81; 95% CI: 0.68, 0.96) and ischemic stroke (per SD increment; adjusted OR: 0.76; 95% CI: 0.62, 0.93). Furthermore, a stronger inverse association between plasma Se and first stroke was observed in participants with higher folate concentrations at baseline (≥ 7.7 (median), adjusted OR: 0.67; 95% CI: 0.54, 0.85, versus <7.7 ng/mL adjusted OR: 0.98; 95% CI: 0.80, 1.21; P for interaction = 0.008), and those with higher time-averaged systolic blood pressure (SBP) over the treatment period (≥ 140, adjusted OR: 0.71; 95% CI: 0.58, 0.86, versus <140 mmHg, adjusted OR: 0.96; 95% CI: 0.77, 1.20; P for interaction = 0.023). CONCLUSIONS In summary, there was a significant inverse association between plasma Se and risk of first stroke in Chinese adults with hypertension, especially among those with higher baseline folate concentrations and those with higher time-averaged SBP over the treatment period.Trial registration number: NCT00794885URL of registration: https://www.clinicaltrials.gov/ct2/show/NCT00794885?term=NCT00794885&draw=2&r.