Purpose: To examine the volumes of the gray and white matter both globally and regionally in patients diagnosed with type 2 diabetes and controls.
Materials and methods: Our samples were comprised of 26 patients with type 2 diabetes, 26 patients with diabetes and major depressive disorder, and 25 nondiabetic, nondepressed control subjects. All subjects were studied cross-sectionally on a 1.5 T scanner and were recruited from medicine/diabetes clinics. Both gray and white matter volumes were estimated using an automated method, and the prefrontal areas studied included the anterior cingulate, the gyrus rectus, and the orbitofrontal regions.
Results: Patients with diabetes, both with and without depression, had smaller total brain gray matter volumes when compared with the control subjects after controlling for age, intracranial volume, and years of education. This group also had smaller gray matter volumes in the anterior cingulate and orbitofrontal regions when compared with the controls after additionally controlling for total gray matter volume. The depressed and nondepressed diabetic groups did not differ on any neuroimaging measure. Cerebrovascular risk factors correlated negatively with gray matter volumes.
Conclusion: The findings indicate that type 2 diabetes is associated with specific neuroanatomical abnormalities in the prefrontal gray matter. Vascular disease might contribute to the findings observed in our sample. These observations have implications for the behavioral sequelae of diabetes.