Abstract P220: Whole Blood Selenium Concentration is Inversely Associated With Prevalence of Stroke: Results From the Canadian Health Measures Survey and the US National Health and Nutrition Examine Survey

Abstract

Introduction: Each year, over 140,000 Americans and 10,000 Canadians die from stroke. Selenium is an essential trace element involved in antioxidant and anti-inflammatory processes, as well as in intracellular redox regulation and modulation. Observational studies have suggested that Se may have beneficial effects on certain cancer and cardiovascular outcomes. Hypothesis: We assessed the hypothesis that blood selenium concentration might be inversely associated with prevalence of stroke and the relationship between blood selenium and prevalence of stroke would be non-linear. Methods: Adult respondents (aged 20 and over) from 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. Age, sex, and other major risk factors for stroke were comparable between the two datasets. Whole blood and urinary selenium were measured in the CHMS, whole blood and serum selenium were measured in the NHANES. First, we examined the differences in selenium concentrations by stroke status. Second, we used logistic regressions to investigate the difference in prevalence of stroke by whole blood Se tertiles, adjusting for established risk factors. Third, we quantified the potential non-linear association between Se and stroke by restricted cubic spline regression. Results: A total of 82 (1.16%) and 202 (4.02%) stroke cases were identified in CHMS and NHANES, respectively. Respondents with stroke had lower Se levels comparing with those without stroke, with a mean difference of 16 μg/L in CHMS and 12 μg/L in NHANES, respectively. Respondents with high blood selenium concentration (tertile 3) had a lower prevalence of stroke compared to those with low selenium 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 cubic restricted spline regression. Each 10-μg/L increase in whole blood selenium was associated with a 14% decreased prevalence of stroke in CHMS and 19% in NHANES. Sensitivity analysis using serum and urinary selenium demonstrate that our results were consistent across different selenium biomarkers. Conclusion: We observed inverse cross-sectional associations between whole blood Se and prevalence of stroke in representative samples of the Canadian and the US population.