CHRNA5 and ischemic stroke: However, the results of a cohort study indicate that the CHRNA5 rs1051730 polymorphism is not significantly linked with ischemic heart disease or ischemic stroke (RR = 0.9, 95% CI = 0.7–1.0; RR = 1.1, 95% CI = 0.8–1.4, respectively) [40].