Abdominal visceral fat accumulation is associated with hippocampus volume in non-dementia patients with type 2 diabetes mellitus.

Obesity is associated with cognitive dysfunction, for which changes in the hippocampus plausibly play a pivotal role. We tested the hypothesis that an elevated level of visceral fat accumulation (VFA) correlates with hippocampus volume and insulin resistance in non-dementia patients with type 2 diabetes. Subjects included 48 non-dementia patients with type 2 diabetes, who were divided into two groups, high VFA group (mean+/-standard deviation: age=65+/-6 years, n=30) and normal VFA group (65+/-5 years, n=18). Hippocampus volume has been quantitated with computer-assisted analysis using a magnetic resonance imaging (MRI) voxel-based specific regional analysis system developed for the study of Alzheimer's disease (VSRAD), which yields a Z-score as the end point for assessment of hippocampal volume. The Z-score was higher in the high VFA group than in the normal VFA group (p<0.0001). The fasting plasma glucose (p<0.05) and insulin concentrations (p<0.0001) and the homeostasis model assessment (HOMA) index (p<0.0001) were higher in the high VFA group than in the normal VFA group. Multiple regression analysis showed that VFA levels were independently predicted by Z-score and HOMA index. Our results indicate that the elevated level of VFA in Japanese non-dementia patients with type 2 diabetes is characterized by increased hippocampus volume and insulin resistance, and that the Z-score and HOMA index are independent predictors of VFA.