Rosiglitazone Effects on Cognition for Adults in Later Life

The study will examine the effects of the insulin-sensitizing agent rosiglitazone on learning and memory for 120 patients diagnosed with MCI. Participants will be randomized to an 18-month trial of rosiglitazone or placebo, followed by a 2-month washout period. At screening and at treatment month 18, all participants will undergo an oral glucose tolerance test (OGTT) to estimate pre- and post- treatment insulin sensitivity and β-cell function. Cognitive measures and blood samples for biochemical assays will be obtained at baseline, treatment months 6, 12, and 18, and washout (two months after completing treatment). During treatment, participants will have safety labs drawn and receive physical assessment of any adverse events, changes in health status, or changes in medication; initially these visits will be done at weeks 2 and 4, and then every three months. For months in which a safety visit is not scheduled, telephone monitoring to assess any health concerns will be conducted. All participants enrolled in the primary study will be approached to participate in an MRI substudy; patients will undergo serial brain MRI before treatment and following 18 months of rosiglitazone or placebo, using three-dimensional T1-weighted images. Comparison of MCI patients receiving rosiglitazone and placebo will be conducted to determine whether the rate of medial temporal lobe (MTL) and whole brain atrophy is altered following treatment.