Diabetes exerts a causal impact on the nervous system within the right hippocampus: substantiated by genetic data

Diabetes and neuronal loss in the hippocampus have been observed to be correlated in several studies; however, the exact causality of this association remains uncertain. This study aims to explore the potential causal relationship between diabetes and the hippocampal nervous system.

We utilized the two-sample Mendelian randomization (MR) analysis to investigate the potential causal connection between diabetes and the hippocampal nervous system. The summary statistics of Genome-wide association study (GWAS) for diabetes and hippocampus neuroimaging measurement were acquired from published GWASs, all of which were based on European ancestry. Several two-sample MR analyses were conducted in this study, utilizing inverse-variance weighted (IVW), MR Egger, and Weight-median methods. To ensure the reliability of the results and identify any horizontal pleiotropy, sensitivity analyses were undertaken using Cochran's Q test and the MR-PRESSO global test.

Causal associations were found between diabetes and the nervous system in the hippocampus. Type 1 and type 2 diabetes were both identified as having adverse causal connections with the right hippocampal nervous system. This was supported by specific ranges of IVW-OR values (P < 0.05). The consistency of the sensitivity analyses further reinforced the main findings, revealing no significant heterogeneity or presence of horizontal pleiotropy.

This study delved into the causal associations between diabetes and the hippocampal nervous system, revealing that both type 1 and type 2 diabetes have detrimental effects on the right hippocampal nervous system. Our findings have significant clinical implications as they indicate that diabetes may play a role in the decline of neurons in the right hippocampus among European populations, often resulting in cognitive decline.