Circulating Selenium Concentration Is Inversely Associated With the Prevalence of Stroke: Results From the Canadian Health Measures Survey and the National Health and Nutrition Examination Survey

BACKGROUND: Observational studies have suggested that selenium (Se) may have beneficial effects against certain cardiovascular outcomes, with a possible U‐shaped association. We assessed the hypothesis that blood Se concentration might be inversely associated with the prevalence of stroke and the relationship would be nonlinear. METHODS AND RESULTS: Data collected from adult participants (aged ≥20 years) in the Canadian Health Measures Survey (CHMS 2007–2011, n=7065) and the US National Health and Nutrition Examination Survey (NHANES 2011–2012, n=5030) were analyzed. A total of 82 (1.16%) and 202 (4.02%) stroke cases were identified in CHMS and NHANES. Respondents with stroke had lower Se levels than those without stroke, with a mean difference of 16 μg/L and 12 μg/L for CHMS and NHANES, respectively. Respondents with high blood Se concentration (tertile 3) had a lower prevalence of stroke compared with those with low Se concentration (tertile 1). The adjusted odds ratios were 0.38 (95% CI: 0.15, 0.92) and 0.57 (95% CI: 0.31, 1.03) for CHMS and NHANES, respectively. A continuous decreasing trend of stroke with whole blood selenium was observed in CHMS, whereas the curve plateaued starting at 190 μg/L for NHANES, based on the cubic restricted spline regression. Sensitivity analysis using the serum and urinary Se concentrations demonstrates that our results were consistent across different selenium biomarkers. CONCLUSIONS: We observed inverse cross‐sectional associations between whole blood Se and the prevalence of stroke in representative samples of the Canadian and the US population.