Metformin use and brain atrophy in nondemented elderly individuals with diabetes

There is a shred of growing evidence demonstrating that diabetic patients are at higher risk of developing Alzheimer's disease compared to the general population. The previous investigation showed the protective effect of metformin for delaying dementia in diabetic patients. However, there are limited data on the effect of metformin on structural changes. This study aims to investigate the effect of metformin on hippocampal and cortical volumes in non-demented diabetic individuals.

We entered 157 non-demented diabetic subjects including 89 mild cognitive impairment (MCI), and 68 cognitively healthy individuals from Alzheimer's disease Neuroimaging Initiative (ADNI) which were then categorized as metformin users and non-users. We used the ANCOVA model for measuring the association between metformin use and hippocampal and cortical volumes.

Among 157 subjects with a mean age of 71.8 (±7.7) included in this study, 76 individuals were stratified as metformin users. Results of the univariate model indicate that metformin users had a higher right (p = 0.003) and left parietal lobe volume (p = 0.004). Moreover, the volume of left cingulate was higher in those who used metformin compared to those not used it (p = 0.027). Our results were also significant for the right frontal lobe and indicated that metformin users had higher volume (p = 0.035). There were no significant differences in the hippocampus, occipital, and temporal regions.

Our findings showed the protective effects of metformin on brain volumes in non-demented elderly individuals with diabetes. Comparing the groups show strong enough results regarding the lower atrophy in metformin users.