When compared with low-dose therapy , high-dose vitamin therapy was associated with higher stroke risk among individuals on antiplatelets ( hazard ratio , 1.43 ; 95 % confidence interval , 1.02-2 .01 ) , but trended toward lower risk among those not on antiplatelets ( hazard ratio , 0.86 ; 95 % confidence interval , 0.62-1 .19 ) .