Mendelian randomization in Alzheimer's disease and mild cognitive impairment: Hippocampal volume associations.

[Display omitted] • Significant hippocampal volume reduction found in MCI and AD patients. • No causal link between hippocampal volume reduction and Alzheimer's disease. • Subfield-specific hippocampal changes in MCI advance understanding of AD. This study investigates the association between cognitive dysfunction and hippocampal volumes in Alzheimer's Disease (AD) and Mild Cognitive Impairment (MCI) using Mendelian randomization. A meta -analysis of 503 healthy controls, 562 MCI patients, and 389 CE patients revealed significant reductions in hippocampal and subregion volumes in MCI and AD compared to controls. While various subregions showed volume reductions, no causal relationship between hippocampal volume and AD was established through Mendelian randomization analysis. In conclusion, significant volume reductions were observed in MCI and AD patients, highlighting the complexity of the relationship between hippocampal volume and cognitive impairment. [ABSTRACT FROM AUTHOR]