Abstract P590: Serum Zinc Levels and Incidence of Ischemic Stroke: The Reasons for Geographic and Racial Differences in Stroke Study

Abstract

Background and Purpose: Despite zinc’s role as an anti-oxidant and anti-inflammatory agent, prospective studies relating zinc levels to ischemic stroke risk are lacking. We aimed to examine the association between serum zinc levels and incidence of ischemic stroke in a US population. Methods: Using a case-cohort study nested within the REGARDS (REasons for Geographic and Racial Differences in Stroke) cohort, participants were randomly selected from the REGARDS cohort to generate a sub-cohort ( n= 2,346). All incident ischemic stroke cases as of September 2012 ( n =660) were included, with 62 incident cases overlapping in the sub-cohort. Serum zinc levels were measured at baseline. Barlow-weighted Cox’s proportional hazards regression models were used to calculate multivariable-adjusted hazard ratios (HR) and the corresponding 95% confidence intervals (CI) of ischemic stroke by serum zinc levels. Results: The median zinc level for the sub-cohort was 121.19 μg/dL (interquartile range 104.86 to 140.39 μg/dL). Serum zinc levels were inversely associated with incidence of ischemic stroke after adjustment for potential confounders (quartile 4 vs. quartile 1: HR=0.78, 95% CI: 0.61-0.98, p=0.03 for trend). When stratified by pre-specified factors (sex, race, region), only sex showed a significant modification (p=0.03 for interaction). The inverse association was more pronounced among females (quartile 4 vs. quartile 1: HR=0.58, 95% CI: 0.41-0.84, p<0.01 for trend) than males (quartile 4 vs. quartile 1: HR=1.08, 95% CI: 0.78-1.51, p=0.92 for trend). Conclusions: Serum zinc concentration was inversely associated with incidence of ischemic stroke, especially among women, indicating that low zinc levels may be a risk factor for ischemic stroke.