Characteristics of study population at baseline.

Age is given as median (interquartile range). Gender and vascular risk factors are reported as absolute number of subjects (%). P-values are calculated using chi-square statistics (categorical variables) and Kruskal-Wallis statistics (continuous variables).SBI: silent brain infarcts; LI: lacunar stroke.年龄以中位数（四分位间距）表示。性别与血管危险因素以受试者绝对数（百分比）形式报告。P值通过卡方检验（分类变量）与Kruskal-Wallis检验（连续变量）计算得出。SBI：无症状性脑梗死（silent brain infarcts）；LI：腔隙性脑卒中（lacunar stroke）。