We assessed circulating lipids and atherosclerotic development in young (6.6 ± 0.1 mo, M/F:17/8), middle-aged (10.1 ± 0.2 mo, M/F: 13/3) and old (16.9 ± 0.1 mo, M/F: 18/14) ApoE−/− mice fed an AD for 3, 5, or 8 weeks. The gene discussed is APOE; the disease is Alzheimer disease.