At study entry, participants will meet inclusion criteria for membership in one of the groups that differ according to cognitive status and metabolic health (described below). Once enrolled, a change in cognitive or metabolic status will not affect eligibility to receive follow-up assessments as part of this study, although frequency of assessment may change (i.e., enrollees who progress to late-stage AD or type 2 diabetes will not be dis-enrolled). Eligible participants who choose to also enroll in ADCC-BIG must agree to complete the LP. If participants have screened or participated in another Kulynych Center study within the last 3 months, some data may be reused to avoid redundant data collection and reduce participant burden. This data may include specimen samples such as blood or CSF, cognitive testing data and MRI imaging data.