Shortened telomeres are a sign of biological ageing of the cardiovascular sytem. In a study from China, researchers investigated telomere length in leukocytes obtained from 1,309 patients with stroke and 1,309 healthy controls. Patients with stroke had significantly shorter telomeres than did controls, and short telomere length was directly associated with a high risk of ischaemic stroke. In follow-up studies, the presence of short telomeres was associated with all-cause mortality, but not with the recurrence of stroke.