Higher insulin resistance was linked to reduced gray matter at baseline and at four years, as well as medial temporal lobe atrophy, in a study of late middle-aged, asymptomatic patients. "This result is important because morphological changes in entorhinal cortex and anterior hippocampus, particularly the cornu ammonis fields, are sensitive to mild cognitive impairment and early Alzheimer's disease relative to normative aging," researchers reported in Diabetes Care.