Objectives: Alzheimer's disease (AD) is increasingly recognized as an important comorbidity of diabetes mellitus and is often accompanied by parahippocampal gyrus atrophy (PGA). But the associations between diabetes-related parameters and PGA are not well known. Voxel-based morphometry (VBM) recently became a popular tool for the early diagnosis of AD. One of the clinically useful tools using magnetic resonance imaging (MRI) is the Voxel-based Specific Regional Analysis system for AD (VSRAD) that evaluates the degree of volume loss of parahippocampal gyrus by comparing grey matter with the original normal database template. We examined the risk factors for PGA by using VSRAD in patients with type 2 diabetes mellitus (T2DM).

Methods: A total of 137 patients aged ≥ 50 years with T2DM (mean age 67.8 ± 9.8 years) underwent brain MRI scans and comprehensive health examinations. Volume of interest (VOI) was measured using VSRAD for each patient. We examined associations between the severity of VOI atrophy and diabetes-related parameters such as HbA1c, fasting plasma glucose (FPG), C-peptide (CPR) index (plasma CPR/FPG x 100) and Hasegawa Dementia Scale-Revised (HDS-R) score, consisting of 9 simple questions with a maximum score of 30. PGA was defined as the VOI atrophy more than 1.0.

Results: Mean HbA1c was 9.3 ± 2.2%. HDS-R (median (range)) score was 28 (12 - 30). CPR index (median (range)) was 1.29 (0.03 - 8.88). The severity of VOI atrophy was more than 1.0 in 36 patients. The VOI atrophy was negatively correlated with HDS-R score (R = - 0.261, p < 0.02). By a using multivariate logistic regression analysis, age (OR 1.08, 95% CI 1.03 - 1.14) and CPR index (OR 0.477, 95% CI 0.233 - 0.977) were significantly associated with PGA.

Conclusions: The HDS-R score was significantly correlated with the VOI atrophy. Older age and lower insulin secretion were significantly associated with PGA in patients with T2DM.


Y. Adachi: None. K. Ota: None. R. Ishii: None. K. Cho: None. Y. Hiramatsu: None. S. Masuda: None. S. Koseki: None. T. Hayashi: None. N. Komatsu: None. E. Ueda: None. Y. Mizuguchi: None. I. Minami: None. T. Yamada: None. T. Watanabe: None.

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