**Figure 2.** DNA methylation Age (**A**) Hannum and Horvath versus chronological age in blood samples. Grey and black circles in the scatterplot denote samples from controls and cases, respectively. The grey line represents a linear regression line through control samples. The black dashed line represents a linear regression line through IS cases. For each subject, age acceleration is defined as the vertical distance to the grey line. The bottom row (**B**) shows how mean age acceleration (y-axis) relates to IS status, with p-value of ANOVA test. By definition, the mean age in controls is zero. Each bar plot reports 1 SE.