A subset of the FHS offspring participants (n = 2,231) underwent brain magnetic resonance imaging (MRI) scanning between 03/1999 and 12/2017 (Figure S1), as previously described12 (link). Briefly, participants were imaged using a 1.5 T MRI (Siemens Medical, Erlangen, Germany) with a 3-dimensional T1-weighted coronal spoiled gradient-recalled echo sequence. All images were transferred to and processed by the University of California Davis Medical Center without knowledge of the clinical information. Segmentation and quantification of the total cerebral cranial volume (TCV), total brain volume, frontal lobe (FBV), parietal lobe (PBV), occipital lobe (OBV), temporal lobe (TBV), hippocampal (HPV), and lateral ventricle volumes were performed using semiautomated procedures as previously described.35 (link) TCV was determined using a convolutional neural network method.36 (link) Nonlinear coregistration of images to the Desikan-Killiany-Tourville atlas enabled the calculation of regional gray matter volumes.14 (link) MRI measures were corrected for head size by calculating the percent of these volumes relative to the TCV. The percentage of TCV was log-transformed for normality. Each image set underwent rigorous quality control, including assessments of the original acquisition and image processing quality.