Persons who had diabetes and were heterozygous for the VDR FokI Ff genotype experienced less decline in the following ROIs: total WM (β(SE) = 9.873 (4.102), P = 0.02), frontal WM (β(SE) = 3.557 (1.755), P = 0.04), temporal WM (β(SE) = 2.412 (1.013), P = 0.02), occipital WM (β(SE) = 1.281 (0.537), P = 0.02), internal capsule (β(SE) = 0.336 (0.137), P = 0.02), and entorhinal cortex (β(SE) = 0.153 (0.062), P = 0.01). This evidence concerns the gene VDR and diabetes mellitus.