Participants were eligible for these analyses if they had genotyping, an MRI, and lacked a history of transient ischemic attack or stroke prior to their MRI (covert MRI-infarcts). Participants were entirely or almost entirely European whites in the AGES-Reykjavik Study, ASPS, FHS and Rotterdam Study, so African American participants from ARIC and CHS were not included in these analyses. In addition, CHS did not genotype participants with any form of clinical cardiovascular disease at baseline. By design, ASPS did not perform MRI scans in patients with transient ischemic attack or stroke. Also ASPS and Rotterdam Study did not perform MRI scans in participants with dementia. The number and characteristics of participants from each cohort are shown in Table 1.
