Although there was no effect of age on whole-brain atrophy rate in controls, a 10-year increase in age from average was associated with a reduction in atrophy rate for AD patients of 3 mL/y (1.03–4.25) after adjusting for WMH and APOE e4 and subtracting the age–atrophy effect in controls. This evidence concerns the gene APOE and Alzheimer disease.